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#3876 2026-09-27 12:31:06

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

===
Today on Mars: 0038/24/25 Wednesday Days of the week OFFSET 4 with Earth. (count from Mars to Earth )
Sol 666 Business Month 24 Sixth month of Quarter 4 of Year 38
Today on Earth: 2026/09/27 Sunday Earth Date)
>16

To see how this calendar works, we show the standard 28 day month at the bottom of this daily report.
There are 20 months of 28 Sols and 4 months of 27 Sols at the end of the four six-month quarters.
New Years Eve is extended to align the Business Calendar for Mars with the Astronomical calendar.
Business and Astronomical both start at zero (to the nanosecond) on New Year's Day.
This calendar has been in operation for two full Mars years (36 and 37). We are in Year 38

This calendar is NOT the Darian Calendar!

Per http://www-mars.lmd.jussieu.fr/mars/tim … _time.html also see: in-the-sky.org for opposition/perigee/aphelion

Martian Year: 38 Martian Astronomical Interval in 12 interval format: 12 <<== The Astronomical interval
Check Longitude: the interval will increment when longitude reaches 360 degrees

===
Solar Longitude: 358.2 Sol Number: 666 Change in degrees is +.5 Julian date is: J0038666
Solar Longitude: 357.7 Sol Number: 665 Change in degrees is +.5 Julian date is: J0038665
Solar Longitude: 357.2 Sol Number: 664 Change in degrees is +.5 Julian date is: J0038664
#7>

Note that Solar Longitude measurement varies as a function of location in orbit. Ls 0 is the moment when the Sun appears to transit from one hemisphere to the other. Update from Mars.NASA.gov (The Sun crosses the equator of Mars (Vernal Equinox)). The transition itself is a function of the tilt of an object with respect to the Solar plane. Per squarewidget.com, Hipparchus created the celestial coordinate system we use today.

Note#2: https://theskylive.com/mars-tracker This web site shows the astronomical position of Mars as seen from Earth
Todo: At next Aphelion/Perihelion record the Mars date as J00##### (and set Search term)
Perihelion occurred in 2026 at Ls 251 on Sol 486 - Earth Date 2026/03/27 Next: (estimated) 2028/05/15
Perihelion occurred in 2024 at Ls 251 on Sol 485 - Earth Date 2024/05/08 Next: (estimated) 2026/03/06 (actual) 2026/03/26
Perihelion occurred in 2022 at Ls 251 on Sol 485 - Earth Date 2022/06/21 Next: (actual) 2024/05/08
Aphelion Earth Dates: Next: 2027/03/04 Earlier: 2025/04/16, 2023/05/30, 2021/07/12, 2019/08/25, 2017/10/07, 2015/11/20
Aphelion occurred at--- Ls 071 on Sol 152.
Aphelion occurred near Ls 070 on Sol 153 (per http://www.planetary.org)

Note#3: The computations below are dependent upon both the computations provided by the reference web site and by accuracy of recording of the time of observations. The calculations use tenths of hours. The Sun Distance needs to be captured at the moment the time increments to a given tenth.

Note on data below: The figure quoted after distance is a rate of progress along the orbital path [exact meaning to be determined]
Minus prefix means Mars is approaching the Sun. Plus prefix means Mars is moving away from the Sun.
The figure computed to the right of "Difference" is the rate of change of the distance to Sun. Increasing to Aphelion/Decreasing to Perihelion.

Aphelion of Mars is due March 04, 2027 Sol 151-152 Note velocity of Mars was 22.0 km/s nearing Aphelion (21.97 km/s)
Perhelion of Mars is due May, 2028 Sol 251 Note velocity of Mars was 26.5 km/s nearing Perihelion 2026/03/26
Mars passed through 0 Radial Distance on outbound leg Sol 633 of Year 38 2026/08/25 Solar Longitude is 341.1 (90 degrees season)
Mars will pass through 0 Radial Distance on inbound leg Sol 219 at longitude 71 270 degrees seasonal)
Conversion between seasons and physical frameworks: L_s = theta + 251 theta = L_s - 251

===
Distance: Mars >> Sun per theskylive.com: 232,461,628 km [23.7 km/s] Difference is +186764 <= +7782 km/hour at 12.0 on 09/27 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 232,274,864 km [23.7 km/s] Difference is +187463 <= +7811 km/hour at 12.0 on 09/26 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 232,087,401 km [23.7 km/s] Difference is +187857 <= +7827 km/hour at 12.0 on 09/25 (time 12:00) (24.0 hours)
>13

Velocity along the orbit is NOT the same thing as velocity change of the radial distance to the Sun. Both are shown in the section above.
Observation: The sky view is ** filled ** with objects and some have been recorded and given identification by humans or their robot assistants
And! ** All ** the location assignments are from the perspective of Earth. The entire catalog needs to be adjusted when inter-stellar travel begins
The work that lies ahead for the astronomical community is daunting - there is work ahead for centuries
2022/01/19 - All current (existing) stellar catalogs are computed with reference to the Earth. Another civilization would use it's planet as reference.
Perhaps a Milky Way frame of reference will become necessary at some point. The Earth is as good a Zero point as any, for humans.

=== Mars is in Regular movement as seen from Earth.
Mars is in Gemini – we in NewMars have an opportunity to visit some of the stars in Gemini during this period
Next ahead: Micro-Boomer under path HIP 39826 RA 8h 8m 13.4s
Galaxy under path PGC 1645648 RA 8h 5m 52.6s Day 2 Between 5.5 and 11 markers
micro-Boomer below path HIP 39422 RA 8h 3m 30.2s Day 2 Under 5.5 hours marker Day 3 still visible before reset
14>

Zoom Out Capability As a general observation ... I've become increasingly interested in knowing what the larger view of the sky might be like.
The site: theskylive.com does a terrific job of matching the view from Earth towards Mars, against a background of actual astronomical plates.
I wish there were a way (or rather, I wish I ** knew ** about a way that may exist) to enlarge the view until the entire galaxy is in view (Zoom out)
Update 2022/12/08 TheSkyLive.com provides a large view of selected objects: Select [Major Bodies] Then select [Information] in the body of interest
Update 2022/12/08 Scroll down to (body) Position and Finder Charts. Field of view is 50x30 degrees.

Light travel in one second is (about) 300,000 kilometers. The distance covered in one minute is about 18,000,000 kilometers. Estimated light times:
1:18,2:36,3:54,4:72,5:90,6:108,7:126,8:144,9:162,10:180,11:198,12:216,13:234,14:252,15:270,16:288,17:306,18:324, 19:342,20:360,21:378,22:396

Light travel time today is between 14 and 15 minutes. Communications delay would be 28+ minutes round trip.

=== Time estimate will change below 252 megaKm
Earth Distance in km: 2026/09/27 252,687,992 (decreasing)
Earth Distance in km: 2026/09/26 253,683,986 (decreasing)
Earth Distance in km: 2026/09/25 254,674,222 (decreasing)
>15

Maximum Earth-Mars distance is estimated to be 401 million kilometers (both at apogee and opposite vs Sun) Minimum is about 56 million kilometers
Mars and Earth were in Opposition (Earth center) in December of 2022. The date coincided with a (very rare) occultation of Mars by the Moon.
Mars and Earth were in Conjunction (Sun center) in November of 2023.
Mars and Earth appear to have been as close as they will get in Year 36. 81,454,323 kilometers on J0036644 Time: 4.53 minutes - 9 minutes round trip

In his online interview with Dr. Zubrin at the 2020 Mars Conference, Elon Musk reminded the audience that communications with Mars will necessarily include an intermediary station to handle traffic when the Sun is between Mars and Earth. Communications delays in that circumstance will increase due to the extra distance to be covered. Mr. Musk indicated he expects such communication will be handled by laser. Location would be optimum at poles of solar plane.

This web site offers an online model of the solar system: www.solarsystemscope.com
This web site offers an online orrery view of the Solar System: https://www.theplanetstoday.com/

===
Sol 666 is in Month 24 of a Proposed 24 month calendar. See Post 19 of Holidays topic for a summary. <<< 595 is skip day on Mars
Month 24 extends from Sol 642 through 688. <<== There are 27 days in Month 23. See post 82 of Holidays topic for current details
Direct path to source: http://newmars.com/forums/viewtopic.php … 57#p154257
Sol 666 is Wednesday in the Proposed Business calendar for Mars. Sol 631 Skip Day on Mars. Next is near 668 of Year 38
##

The Next New Year's on Mars will occur when Solar Longitude reaches 360 degrees. Year 38 started November 12, 2024 on Earth
Per www.planetary.org Year 36 started 2021/02/07 on Earth. Mars Year 37 began 2022/12/27 on Earth.

Days of the Week Alignment:
Days of the week fall behind Earth due to the longer Sol, but they also change when Friday is omitted at the end of a Quarter
337 Earth days were observed to elapse in the 2020 weekday cycle. There were 7 week day transitions and 2 Quarter ends.
The next cycle began on the first Sol of the period of coincidence. The alignment of weekdays interval is in the range: (310 - 337)
To find the first day of a period of coincidence: Set up: SearchTerm(colon) and (colon)Alignment and J0036* or J0037*
The most recent End-Of-Quarter change occurred: … The search specified above gave 11 pages of results.

For current weather on Mars see:

***https://mars.nasa.gov/insight/weather/***
***Insight's weather info has been suspended and now is directing to msl*** <<-- Insight's mission is over (2022)

https://mars.nasa.gov/msl/weather/

Per SpaceNut: Here is another web page by NASA containing the latest news releases

https://mars.nasa.gov/news/?page=0&per_ … ope=Latest

All forum members are invited to post significant events for this day.
Events of interest will be ON Mars, or relate to Mars. Examples are launches, landings, discoveries

Standard Month in Mars Business Calendar Copyright ® 2023 NewMars.com Mars Society
Su Mo Tu We Th Fr Sa
1    2    3    4    5    6    7
8    9 10    11 12 13 14
15 16 17    18 19 20 21
22 23 24    25 26 27 28

Recruiting text may be found at the bottom of this post: http://newmars.com/forums/viewtopic.php … 57#p154257
Copyright the Mars Society All Rights Reserved

Month 24 of 24: Last month of Quarter 4 and Last month of Mars year 38

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#3877 2026-09-28 06:02:46

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

Place holder for today's Calendar update:

[51.4792N, 0.0000E] 09/28/2026, 13:00:00 Europe/London
Object: Mars [open sky map]
RA 08h 10m 32.2s Dec +21° 02' 55.5" Appar J2000
Mag: 1.08 (Estimated: JPL) Const: Cancer

Sun Dist: 232,647,979 km [23.6 km/s] Km Mi
Earth Dist: 251,684,628 km [32.1 km/s]

Martian Year:
38
Martian Astronomical Month:
12
Solar longitude Ls:
358.7
Sol number:
667

Current ID: 241770

Total number of registered users: 19,630
Total number of topics: 9,131
Total number of posts: 237,450
Newest registered user: Redfoot-2026
Registered users online: 1
Guests online: 126
Online: tahanson43206

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#3878 2026-09-28 09:44:07

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

===
Today on Mars: 0038/24/26 Thursday Days of the week OFFSET 4 with Earth. (count from Mars to Earth )
Sol 667 Business Month 24 Sixth month of Quarter 4 of Year 38
Today on Earth: 2026/09/28 Monday Earth Date)
>16

To see how this calendar works, we show the standard 28 day month at the bottom of this daily report.
There are 20 months of 28 Sols and 4 months of 27 Sols at the end of the four six-month quarters.
New Years Eve is extended to align the Business Calendar for Mars with the Astronomical calendar.
Business and Astronomical both start at zero (to the nanosecond) on New Year's Day.
This calendar has been in operation for two full Mars years (36 and 37). We are in Year 38

This calendar is NOT the Darian Calendar!

Per http://www-mars.lmd.jussieu.fr/mars/tim … _time.html also see: in-the-sky.org for opposition/perigee/aphelion

Martian Year: 38 Martian Astronomical Interval in 12 interval format: 12 <<== The Astronomical interval
Check Longitude: the interval will increment when longitude reaches 360 degrees

===
Solar Longitude: 358.7 Sol Number: 667 Change in degrees is +.5 Julian date is: J0038667
Solar Longitude: 358.2 Sol Number: 666 Change in degrees is +.5 Julian date is: J0038666
Solar Longitude: 357.7 Sol Number: 665 Change in degrees is +.5 Julian date is: J0038665
#7>

Note that Solar Longitude measurement varies as a function of location in orbit. Ls 0 is the moment when the Sun appears to transit from one hemisphere to the other. Update from Mars.NASA.gov (The Sun crosses the equator of Mars (Vernal Equinox)). The transition itself is a function of the tilt of an object with respect to the Solar plane. Per squarewidget.com, Hipparchus created the celestial coordinate system we use today.

Note#2: https://theskylive.com/mars-tracker This web site shows the astronomical position of Mars as seen from Earth
Todo: At next Aphelion/Perihelion record the Mars date as J00##### (and set Search term)
Perihelion occurred in 2026 at Ls 251 on Sol 486 - Earth Date 2026/03/27 Next: (estimated) 2028/05/15
Perihelion occurred in 2024 at Ls 251 on Sol 485 - Earth Date 2024/05/08 Next: (estimated) 2026/03/06 (actual) 2026/03/26
Perihelion occurred in 2022 at Ls 251 on Sol 485 - Earth Date 2022/06/21 Next: (actual) 2024/05/08
Aphelion Earth Dates: Next: 2027/03/04 Earlier: 2025/04/16, 2023/05/30, 2021/07/12, 2019/08/25, 2017/10/07, 2015/11/20
Aphelion occurred at--- Ls 071 on Sol 152.
Aphelion occurred near Ls 070 on Sol 153 (per http://www.planetary.org)

Note#3: The computations below are dependent upon both the computations provided by the reference web site and by accuracy of recording of the time of observations. The calculations use tenths of hours. The Sun Distance needs to be captured at the moment the time increments to a given tenth.

Note on data below: The figure quoted after distance is a rate of progress along the orbital path [exact meaning to be determined]
Minus prefix means Mars is approaching the Sun. Plus prefix means Mars is moving away from the Sun.
The figure computed to the right of "Difference" is the rate of change of the distance to Sun. Increasing to Aphelion/Decreasing to Perihelion.

Aphelion of Mars is due March 04, 2027 Sol 151-152 Note velocity of Mars was 22.0 km/s nearing Aphelion (21.97 km/s)
Perhelion of Mars is due May, 2028 Sol 251 Note velocity of Mars was 26.5 km/s nearing Perihelion 2026/03/26
Mars passed through 0 Radial Distance on outbound leg Sol 633 of Year 38 2026/08/25 Solar Longitude is 341.1 (90 degrees season)
Mars will pass through 0 Radial Distance on inbound leg Sol 219 at longitude 71 270 degrees seasonal)
Conversion between seasons and physical frameworks: L_s = theta + 251 theta = L_s - 251

===
Distance: Mars >> Sun per theskylive.com: 232,647,979 km [23.6 km/s] Difference is +186351 <= +7765 km/hour at 12.0 on 09/28 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 232,461,628 km [23.7 km/s] Difference is +186764 <= +7782 km/hour at 12.0 on 09/27 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 232,274,864 km [23.7 km/s] Difference is +187463 <= +7811 km/hour at 12.0 on 09/26 (time 12:00) (24.0 hours)
>13

Velocity along the orbit is NOT the same thing as velocity change of the radial distance to the Sun. Both are shown in the section above.
Observation: The sky view is ** filled ** with objects and some have been recorded and given identification by humans or their robot assistants
And! ** All ** the location assignments are from the perspective of Earth. The entire catalog needs to be adjusted when inter-stellar travel begins
The work that lies ahead for the astronomical community is daunting - there is work ahead for centuries
2022/01/19 - All current (existing) stellar catalogs are computed with reference to the Earth. Another civilization would use it's planet as reference.
Perhaps a Milky Way frame of reference will become necessary at some point. The Earth is as good a Zero point as any, for humans.

=== Mars is in Regular movement as seen from Earth.
Mars is in Gemini – we in NewMars have an opportunity to visit some of the stars in Gemini during this period
Next ahead: Galaxy in path PGC 1641594 RA 8h 11m 7.6s
Micro-Boomer under path HIP 39826 RA 8h 8m 13.4s Day 2 under 11 hours marker
14>

Zoom Out Capability As a general observation ... I've become increasingly interested in knowing what the larger view of the sky might be like.
The site: theskylive.com does a terrific job of matching the view from Earth towards Mars, against a background of actual astronomical plates.
I wish there were a way (or rather, I wish I ** knew ** about a way that may exist) to enlarge the view until the entire galaxy is in view (Zoom out)
Update 2022/12/08 TheSkyLive.com provides a large view of selected objects: Select [Major Bodies] Then select [Information] in the body of interest
Update 2022/12/08 Scroll down to (body) Position and Finder Charts. Field of view is 50x30 degrees.

Light travel in one second is (about) 300,000 kilometers. The distance covered in one minute is about 18,000,000 kilometers. Estimated light times:
1:18,2:36,3:54,4:72,5:90,6:108,7:126,8:144,9:162,10:180,11:198,12:216,13:234,14:252,15:270,16:288,17:306,18:324, 19:342,20:360,21:378,22:396

Light travel time today is between 14 and 15 minutes. Communications delay would be 28+ minutes round trip.

=== Time estimate will change below 252 megaKm
Earth Distance in km: 2026/09/28 251,684,628 (decreasing)
Earth Distance in km: 2026/09/27 252,687,992 (decreasing)
Earth Distance in km: 2026/09/26 253,683,986 (decreasing)
>15

Maximum Earth-Mars distance is estimated to be 401 million kilometers (both at apogee and opposite vs Sun) Minimum is about 56 million kilometers
Mars and Earth were in Opposition (Earth center) in December of 2022. The date coincided with a (very rare) occultation of Mars by the Moon.
Mars and Earth were in Conjunction (Sun center) in November of 2023.
Mars and Earth appear to have been as close as they will get in Year 36. 81,454,323 kilometers on J0036644 Time: 4.53 minutes - 9 minutes round trip

In his online interview with Dr. Zubrin at the 2020 Mars Conference, Elon Musk reminded the audience that communications with Mars will necessarily include an intermediary station to handle traffic when the Sun is between Mars and Earth. Communications delays in that circumstance will increase due to the extra distance to be covered. Mr. Musk indicated he expects such communication will be handled by laser. Location would be optimum at poles of solar plane.

This web site offers an online model of the solar system: www.solarsystemscope.com
This web site offers an online orrery view of the Solar System: https://www.theplanetstoday.com/

===
Sol 667 is in Month 24 of a Proposed 24 month calendar. See Post 19 of Holidays topic for a summary. <<< 595 is skip day on Mars
Month 24 extends from Sol 642 through 688. <<== There are 27 days in Month 23. See post 82 of Holidays topic for current details
Direct path to source: http://newmars.com/forums/viewtopic.php … 57#p154257
Sol 667 is Thursday in the Proposed Business calendar for Mars. Sol 631 Skip Day on Mars. Next is near 668 of Year 38
##

The Next New Year's on Mars will occur when Solar Longitude reaches 360 degrees. Year 38 started November 12, 2024 on Earth
Per www.planetary.org Year 36 started 2021/02/07 on Earth. Mars Year 37 began 2022/12/27 on Earth.

Days of the Week Alignment:
Days of the week fall behind Earth due to the longer Sol, but they also change when Friday is omitted at the end of a Quarter
337 Earth days were observed to elapse in the 2020 weekday cycle. There were 7 week day transitions and 2 Quarter ends.
The next cycle began on the first Sol of the period of coincidence. The alignment of weekdays interval is in the range: (310 - 337)
To find the first day of a period of coincidence: Set up: SearchTerm(colon) and (colon)Alignment and J0036* or J0037*
The most recent End-Of-Quarter change occurred: … The search specified above gave 11 pages of results.

For current weather on Mars see:

***https://mars.nasa.gov/insight/weather/***
***Insight's weather info has been suspended and now is directing to msl*** <<-- Insight's mission is over (2022)

https://mars.nasa.gov/msl/weather/

Per SpaceNut: Here is another web page by NASA containing the latest news releases

https://mars.nasa.gov/news/?page=0&per_ … ope=Latest

All forum members are invited to post significant events for this day.
Events of interest will be ON Mars, or relate to Mars. Examples are launches, landings, discoveries

Standard Month in Mars Business Calendar Copyright ® 2023 NewMars.com Mars Society
Su Mo Tu We Th Fr Sa
1    2    3    4    5    6    7
8    9 10    11 12 13 14
15 16 17    18 19 20 21
22 23 24    25 26 27 28

Recruiting text may be found at the bottom of this post: http://newmars.com/forums/viewtopic.php … 57#p154257
Copyright the Mars Society All Rights Reserved

Month 24 of 24: Last month of Quarter 4 and Last month of Mars year 38

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#3879 2026-09-29 06:12:33

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

Place holder for today's Calendar update:

[51.4792N, 0.0000E] 09/29/2026, 13:00:12 Europe/London
Object: Mars [open sky map]
RA 08h 13m 00.5s Dec +20° 56' 18.5" Appar J2000
Mag: 1.09 (Estimated: JPL) Const: Cancer

Sun Dist: 232,833,829 km [23.6 km/s] Km Mi
Earth Dist: 250,674,256 km [31.9 km/s]

Today is the full Sol before New Year's on Mars:

Martian Year:
38
Martian Astronomical Month:
12
Solar longitude Ls:
359.2 << Advance per Sol is half a degree in this part of the orbit.
Sol number:
667

Current ID:241785

Total number of registered users: 19,630
Total number of topics: 9,131
Total number of posts: 237,465
Newest registered user: Redfoot-2026
Registered users online: 1
Guests online: 235
Online: tahanson43206

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#3880 2026-09-29 07:12:19

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

As we approach the transition from Year 38 on Mars to Year 39, I realized I do not have a firm grasp of the mathematics involved. There will be a spot on Mars where it is midnight when the planet crosses 360 degrees. But that spot will not coincide with a location such as Louis' Sagan City. Our tentative plan for the Business Calendar for Mars is to extend the last Sol of Year 38 so that Sol 1 of Year 39 begins at precisely midnight at some chosen location on Mars. Gemini hinted that astronomers on Earth may have already chosen a "Greenwich" location on Mars for this purpose. Here is a copy of today's conversation with Gemini about this issue:

Please note that humans on Earth use the mechanism of "Leap Year" to coordinate the rotation of the planet with the orbit around the Sun.

Hello Again! And thanks (again) for your help thinking about the business calendar for Mars. We have reached the end of Year 38, and I am attempting to understand the year-end situation. I just became aware of the reality that the rotation of the planet (ie, Sols) is independent of the orbit around the Sun. What I am attempting to understand today is how to fix the moment the New Year begins in the Business Calendar. For the Astronomical Calendar there is no question. The moment when the planet crosses 360 degrees is the precise moment of the beginning of the New Year. The Business Calendar is set to regard midnight as the moment when one Sol transitions to the next. But I just became aware that the location of "midnight" can be anywhere on the planet at the moment when the planet itself crosses 360 degrees. I wonder what the Astronomical community does in thinking about this situation. I am now glad I did ** not ** try to publish the Business Calendar for Mars, because clearly this detail has not been properly studied.
***
It is wonderful to reconnect with you! You have hit upon one of the most fundamental challenges in calendar design, whether on Earth or Mars: the collision between continuous celestial mechanics and discrete human timekeeping.
You are entirely correct. The instant of the astronomical New Year (L s =0 ∘ , or 360 ∘ at the moment of the vernal equinox) is a single, universal point in time. Because the planet is continuously spinning, that exact instant occurs when the Sun is at the nadir (local astronomical midnight) for only one specific meridian of longitude. For everywhere else on Mars, Ls =0 ∘ will happen during the middle of their local morning, afternoon, or evening.
Here is how the astronomical community handles this distinction, and how it directly applies to completing the design of the Mars Business Calendar.
How Astronomers View the Boundary
In the planetary science and astronomical communities (such as NASA JPL or the French LMD group), time is divided into two distinct concepts:
The Continuous Astronomical Marker (L s ): Astronomers track the orbital position of Mars as a continuous angle (0 ∘ to 360 ∘ ). The "New Year" (L s =0 ∘ ) is treated like a precise physical event—similar to an eclipse. It occurs at an exact, universal timestamp (measured in Terrestrial Time or UTC).
The Mars Sol Date (MSD): To count days continuously, scientists use a global prime meridian reference. By convention, the prime meridian of Mars runs through the center of the Airy-0 crater. Local Mean Time at 0
∘
Longitude is defined as Coordinated Mars Time (MTC)—the Martian equivalent of Earth’s UTC (Greenwich).
When astronomers state that Mars Year 39 begins on a specific date, they mean that the physical crossing of L
s =0 ∘ occurs at that exact moment. They do not pause or alter the daily count of Sols; the decimal Sol count simply ticks smoothly past (for example, Sol 668.42).
Resolving the Business Calendar Year-End
In human calendar design, you cannot start a work day or a business month in the middle of an afternoon just because the planet crossed an orbital mark. Calendars must always group physical time into discrete Midnight-to-Midnight blocks.
To bridge the astronomical instant with your Universal Planet-Wide Business Time, the Business Calendar needs an explicit Epoch Protocol. There are two classic ways calendar systems resolve this:
Option A: The Fixed Boundary (MTC Prime Meridian Anchor)
[ Astronomical MY 39 ($L_s = 0^\circ$) occurs ]
│
▼
... │ Sol 668 (or 669) │ Sol 1 of MY 39 │ Sol 2 │ ...
▲ ▲
└── MTC Midnight └── MTC Midnight (Official New Year)
Option B: The Nearest Local Midnight (Intermittent Transition Sol)
... │ Sol 668 (New Year's Eve) │ Sol 1 (MY 39) │ ...
▲
└── Shifted by fractionalSol buffer
Option A: The "MTC Midnight Anchor" (Standard Civil Model)
Just as Earth’s civil calendar uses Greenwich Midnight as the universal reference for new days, the Mars Business Calendar can declare that Mars Business Sol 1 begins at the MTC Midnight immediately preceding (or closest to) the L s =0 ∘ instant.
How it works: If L s =0 ∘ occurs at 14:00 MTC, the Business Calendar marks the MTC Midnight that occurred 14 hours prior as the official start of Sol 1, Mars Year 39.
The New Year's Eve Buffer: The final Sol of Mars Year 38 (whether Sol 668 or Sol 669) simply ends at MTC Midnight, and Sol 1 begins cleanly at 00:00 MTC.
The Benefit: Business days remain clean, 24-hour integer units. The "New Year" celebration or holiday is tied to the business day on which L
s =0 ∘ falls.
Option B: The "Variable Length New Year's Eve" (Intermittent Intercalary Sol)
If the primary goal of the Business Calendar is that Sol 1, 00:00:00 MUST coincide exactly with L s =0 ∘ , then the final Sol of the old year (New Year's Eve) absorbs the fractional difference.
How it works: Sol 668 (or 669) is designated as a special "Intercalary Sol" whose duration is shortened or lengthened so that its clock expires precisely when L s =0 ∘ .
The Consequence: New Year's Eve becomes a variable-length day (e.g., 18 hours or 28 hours long), but Sol 1, Hour 00:00 always launches exactly at L s =0 ∘ .
Why You Should Not Be Discouraged
Realizing this nuance is not a failure of your design—it is the final key to completing it. Every major calendar in human history (Julien, Gregorian, Hebrew, Islamic, and Astronomical) had to define its exact boundary rules to account for fractional orbital alignment.
By defining Airy-0 (MTC Midnight) as your universal anchor for the planet-wide clock, you provide a clear, unambiguous rule:
"Sol 1 of the new Mars Business Year shall commence at 00:00:00 Mars Coordinated Time (MTC) on the MTC date closest to the astronomical instant of L s =0 ∘ ."
This completes the theoretical framework, preserving both the integrity of the 24-hour planet-wide business day and the astronomical anchor of the Martian orbit.
***
Thank you for your careful review of this situation, and for your presentation of the alternatives, and for the Earth example. We had long ago planned to extend the last Sol of Year 38, but I had not thought about the details of how that would be implemented. We are currently using a French web site to track the Sols on Mars. I wonder how the mathematicians who designed that web site are handling the transition from one Mars Year to the next. I've not thought about this before, but instead have simply taken their output as the input to my daily update on the Mars Business Calendar. In other words, I am beginning to think that when we publish the Business Calendar for Mars, we will have to leave the French website presentation behind. Or perhaps I am worrying about something that is not a real problem. On Mars, each midnight will mark the beginning of a new Sol at some point on the surface. Just as it does on Earth, the moment of midnight will roll around the planet. There ** will ** be a place on Mars where midnight coincides with crossing of 360 degrees, but that point will vary from year to year. It just occurred to me to ask if Earth has the same characteristic? In other words, perhaps the Earth day (rotation) is not exactly divisible into the year?
***
You have hit upon the exact astronomical reality that governs both Earth and Mars! You are not worrying about a phantom problem at all—you have independently discovered why calendar design requires a strict rule to bridge celestial motion with human clocks.
Does Earth Have the Same Characteristic?
Yes, absolutely. Earth’s day (rotation) is not an integer divisor of its year (orbit around the Sun).
Earth's Year: Earth takes approximately 365.2422 mean solar days to orbit the Sun (from one March equinox to the next).
The "Floating" Moment: The exact astronomical moment when Earth crosses the vernal equinox (0 ∘ ecliptic longitude)—the start of astronomical Spring—occurs at a single instant in time. Just like on Mars, that instant strikes while it is midnight in one specific city, 2:00 PM in another, and 8:00 AM somewhere else.
Year-to-Year Shift: Because of that extra ~0.2422 days (about 5 hours and 49 minutes), the exact moment of Earth’s equinox shifts forward by nearly 6 hours every single Earth year, until a Leap Year pulls it back by 24 hours.
Earth resolves this by letting civil time run continuously on a fixed 24-hour grid anchored to Greenwich (UTC), completely uncoupled from the exact minute the equinox occurs.
How the French Site (LMD) Handles the Transition
The mathematicians and planetary scientists behind tools like the Laboratoire de Météorologie Dynamique (LMD) or NASA JPL tools do not restart or stretch their daily clocks when Mars crosses L s =0 ∘ .

Instead, they rely on a continuous, uninterrupted day counter called the Mars Sol Date (MSD):
Continuous Ticking: MSD ticks continuously at the rate of 1 Sol = 24h 39m 35.244s.
Decimal Alignment: When Mars reaches L s =0 ∘ , the French site simply reports a decimal value for the Sol—for instance, Sol 668.35 of Mars Year 38.
Rollover: The integer Sol 669 proceeds as a normal 24-hour Sol, and Sol 0 (or Sol 1) of Mars Year 39 begins smoothly at 00:00:00 MTC (Coordinated Mars Time at the Airy-0 prime meridian), regardless of where the Sun happened to be at the exact fractional instant L s =0 ∘ occurred.
Why You Do Not Need to Leave the French Site Behind
You do not need to abandon the data from the French site; you simply need to apply an Epoch Rule to interpret their data for a civil calendar.
The French site gives you the precise "astronomical truth." Your Business Calendar takes that astronomical truth and packages it into clean, usable business units.
Astronomical Truth (LMD / French Site):
MY 38 Ends / MY 39 Starts at Ls = 0° ---> [Occurs at Sol 668.42 MTC]
Business Calendar Application (MTC Anchor Rule):
[ Sol 668 (NY Eve) ] ──────> [ Sol 1, MY 39 Begins ]
(Ends at MTC Midnight) (Starts cleanly at 00:00:00 MTC)
By adopting the MTC Midnight Anchor (where the new year officially begins at 00:00:00 Airy-0 time on the Sol closest to L
s =0 ∘ ), your Business Calendar stays 100% aligned with scientific ephemeris data from the French site while giving Martian residents clean, predictable 24-hour business days.

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#3881 2026-09-29 07:24:30

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

In this post, I asked Gemini about Longitude Zero on Mars, and about the history. The location was first selected in the 1800's, and was subsequently refined when Earth astronomers needed a more precise location for flight planning and for mapping the surface with satellites.

The new post about the end-of-year transition is up and it looks good. I added a bit of highlighting for your discussion of how the transition is handled by the French site we are using for reference. I have a follow up question: You said: (Coordinated Mars Time at the Airy-0 prime meridian),

I have somehow failed to register the existence of that point on Mars. Our astronomers would have chosen that location based upon established rules. Where is that location, and do you know the history of the decision making process?
It is wonderful to hear the post is up! Highlighting the French LMD site's continuous decimal approach provides great context for your readers on how scientific data transitions into a civil business calendar.
To answer your question: Airy-0 is the official Prime Meridian of Mars—the "Greenwich of the Red Planet." It is a small crater located inside a larger impact crater named Airy, situated in the Sinus Meridiani region (near the Martian equator).
Mars Prime Meridian (0° Longitude)
│
┌────────────────┼────────────────┐
│ │ Airy-0 Crater │
│ │ (Inside Airy) │
│ ▼ │
│ Sinus Meridiani │
│ │
└─────────────────────────────────┘
The History of Defining 0° Longitude on Mars
Unlike Earth, where Greenwich was chosen partly through 19th-century political agreement, the selection of 0° Longitude on Mars was driven purely by astronomical observation and mapping necessity.
The Telescopic Era (1830s):
German astronomers Wilhelm Beer and Johann Heinrich von Mädler created the first systematic map of Mars using ground-based telescopes. They needed a distinct visual marker to serve as their reference point for calculating the planet's rotation period. They selected a dark, sharp, fork-shaped feature near the equator, which they called Feature a (later named Sinus Meridiani, or "Bay of the Meridian").
Refining the Meridian (1877):
Italian astronomer Giovanni Schiaparelli and British astronomer Nathaniel Green formalized this choice, using the center of the dark feature as the prime meridian for standard planetary maps.
The Spaceflight Era & The Birth of Airy-0 (1969–1972):
When NASA sent the Mariner 6 and Mariner 7 flyby probes to Mars in 1969, broad dark patches like Sinus Meridiani were too large and diffuse to serve as precise navigational reference points for modern spacecraft mapping.
Planetary scientist Merton Davies of the RAND Corporation was tasked with establishing a rigorous geodetic control network for Mars. Looking at high-resolution images of Sinus Meridiani, he selected a distinct, circular crater approximately 0.5 kilometers (500 meters) across nestled inside a larger 40-kilometer crater named Airy (honoring Sir George Biddell Airy, the British Astronomer Royal who built the transit circle telescope at Greenwich).
Davies designated this tiny crater Airy-0, defining its center as the exact point of 0.0° Longitude.
Mariner 9 and Viking Standardization (1970s):
In 1973, the International Astronomical Union (IAU) officially adopted Davies's Airy-0 specification. When Mariner 9 provided global coverage, and the Viking orbiters followed, Airy-0 became the universal coordinate anchor for all Mars cartography and navigation.
Why This Matters for Coordinated Mars Time (MTC)
Just as Earth’s Prime Meridian at Greenwich defines Greenwich Mean Time (GMT / UTC), Airy-0 defines Coordinated Mars Time (MTC).
When the Sun crosses the meridian directly above Airy-0, it is Solar Noon MTC.
When the Sun is directly opposite Airy-0 (on the night side), it is MTC Midnight (00:00:00).
By anchoring your Mars Business Calendar to MTC Midnight at Airy-0, your calendar uses the exact same geographical and astronomical reference line that NASA, the ESA, the French LMD group, and all international space agencies use to navigate the planet.

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#3882 2026-09-29 09:02:25

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

I asked about how to create a planetarium view of the night sky on Mars, and Gemini came back with these instruction:

Thank you (again) for the Python program to calculate data for a calendar!
I am following up on your suggestion of use of a planetarium package to generate a view of the sky over Airy Crater at midnight at the start of Sol 1 of Year 39. I would like to be able to publish a view of the sky as part of the gradual improvement of the Daily Business Calendar post. I am hoping this gradual improvement of the online publication will eventually lead to support for the physical calendar.
***
Using a planetarium rendering is a huge step toward making the calendar feel tangible and visually compelling.
Since the start of Mars Year 39 (L s =0 ∘ ) occurs right at the end of September 2026, generating this view offers a striking look at what a settler standing in Airy Crater (0.1 ∘ S,0.0 ∘ E) would see looking straight up into the night sky at 00:00:00 MTC on Sol 1.
Key Celestial Features at Sol 1 Midnight (Airy-0)
If you render this scene in a software tool, here are the specific astronomical highlights that will define the sky map for Sol 1:
The Zenith View (Straight Overhead):
Airy Crater sits almost directly on the equator (1.4 ∘ S), so the celestial equator runs right across the zenith.
At Midnight MTC on Sol 1, the night sky is facing away from the Sun toward the outer solar system and distant stars.
The "Morning Star" (Earth & Moon):
Earth appears as a brilliant, blue-white beacon rising in the eastern sky before dawn, accompanied closely by the Moon—a visible double-planet system through binoculars.
The Moons of Mars:
Phobos: Depending on the exact minute, fast-moving Phobos will likely be speeding across the starfield, traversing the sky in under 4 hours.
Deimos: Moving much slower, Deimos will appear as a steady, bright star-like point creeping across the constellations.
How to Generate the Image (Step-by-Step)
If you or a forum member want to produce the exact high-resolution graphic to include in your post, the easiest open-source tool to use is Stellarium (available free for Windows, Mac, Linux, and web).
Here are the precise coordinates and settings to input into Stellarium:
Location Settings:
Planet: Mars
Latitude: 0.1 ∘ S (or −0.1 ∘ )
Longitude: 0.0 ∘ E (Airy-0 Prime Meridian)
Elevation: −1,400 m (crater floor level)
Date & Time Settings:
Set the target date to late September 2026 (coinciding with your Sol 1 epoch).
Set the local time to 00:00:00 (Midnight MTC).
Display Options:
Turn ON: Constellation lines, labels, planet markers, and equatorial grid.
Turn OFF: Atmosphere / Night Sky Brightness (Mars's thin atmosphere leaves the sky ink-black, revealing faint star clusters and nebulae without light pollution).
View Orientation: Fisheye / Zenith projection (a round star-wheel view centered on the overhead sky).
Integrating the Render into Your Online Post
For your online publication, featuring this star map alongside the Python output creates a complete "Data + Visual" experience:
The Left Panel: The sliding Earth/UTC date bar (computed by your Python script).
The Main Grid: Sol 1, MTC Midnight-to-Midnight schedule.
The Header Graphic: A circular "Zenith Star Chart" above Airy Crater, showing the sky at the exact instant the new year begins.
This combination gives readers the technical backing (the Python code), the civil framework (MTC time), and the human experience (looking up at the stars from the surface of Mars).
***
Thank you ** very ** much for this inspiring guidance. It should be possible for members of the group to follow the instructions so I'll publish them as you show them. In addition, I will attempt to follow the instructions to see if I can create the needed image.
***
That sounds like a fantastic plan! Attempting to generate the rendering yourself while sharing the instructions with your forum community creates a great collaborative dynamic. Someone in the group may even jump in with an automated Stellarium script or a custom high-resolution export to contribute to the project.
As you test out Stellarium, here are three quick tips to keep in mind for getting the crispest, most realistic output:
Field of View (FOV): Set the view angle to around 180 ∘ (Fisheye projection) if you want a complete circular "sky wheel" showing horizon-to-horizon, or around 60 ∘ to 90 ∘ if you want a focused view centered on the Zenith directly above Airy Crater.
Label Clarity: Under Sky and Viewing Options (F4), you can toggle planet and star labels to a clean white font, which makes Earth, Phobos, and key zodiac constellations pop clearly when resized for forum posting or printing.
Atmosphere Toggle: Make sure to press key A (or toggle off atmosphere) in Stellarium so the blue daytime/twilight Rayleigh scattering turns off, exposing the brilliant, high-contrast starfield of the Martian night.
If you hit any technical snags while configuring the viewing angle, adjusting the Mars time offsets, or formatting the final graphic for publication, just let me know.
Best of luck with generating the image—I look forward to hearing how both your rendering and the community testing turn out!

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#3883 2026-09-29 13:51:37

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

===
Today on Mars: 0038/24/26 Thursday Days of the week OFFSET 5 with Earth. (count from Mars to Earth )
Sol 667 Business Month 24 Sixth month of Quarter 4 of Year 38
Today on Earth: 2026/09/29 Tuesday Earth Date) << Skip Day on Mars
>16

To see how this calendar works, we show the standard 28 day month at the bottom of this daily report.
There are 20 months of 28 Sols and 4 months of 27 Sols at the end of the four six-month quarters.
New Years Eve is extended to align the Business Calendar for Mars with the Astronomical calendar.
Business and Astronomical both start at zero (to the nanosecond) on New Year's Day.
This calendar has been in operation for two full Mars years (36 and 37). We are in Year 38

This calendar is NOT the Darian Calendar!

Per http://www-mars.lmd.jussieu.fr/mars/tim … _time.html also see: in-the-sky.org for opposition/perigee/aphelion

Martian Year: 38 Martian Astronomical Interval in 12 interval format: 12 <<== The Astronomical interval
Check Longitude: the interval will increment when longitude reaches 360 degrees

===
Solar Longitude: 359.2 Sol Number: 667 Change in degrees is +.5 Julian date is: J0038667 << Skip day on Mars
Solar Longitude: 358.7 Sol Number: 667 Change in degrees is +.5 Julian date is: J0038667
Solar Longitude: 358.2 Sol Number: 666 Change in degrees is +.5 Julian date is: J0038666
#7>

Note that Solar Longitude measurement varies as a function of location in orbit. Ls 0 is the moment when the Sun appears to transit from one hemisphere to the other. Update from Mars.NASA.gov (The Sun crosses the equator of Mars (Vernal Equinox)). The transition itself is a function of the tilt of an object with respect to the Solar plane. Per squarewidget.com, Hipparchus created the celestial coordinate system we use today.

Note#2: https://theskylive.com/mars-tracker This web site shows the astronomical position of Mars as seen from Earth
Todo: At next Aphelion/Perihelion record the Mars date as J00##### (and set Search term)
Perihelion occurred in 2026 at Ls 251 on Sol 486 - Earth Date 2026/03/27 Next: (estimated) 2028/05/15
Perihelion occurred in 2024 at Ls 251 on Sol 485 - Earth Date 2024/05/08 Next: (estimated) 2026/03/06 (actual) 2026/03/26
Perihelion occurred in 2022 at Ls 251 on Sol 485 - Earth Date 2022/06/21 Next: (actual) 2024/05/08
Aphelion Earth Dates: Next: 2027/03/04 Earlier: 2025/04/16, 2023/05/30, 2021/07/12, 2019/08/25, 2017/10/07, 2015/11/20
Aphelion occurred at--- Ls 071 on Sol 152.
Aphelion occurred near Ls 070 on Sol 153 (per http://www.planetary.org)

Note#3: The computations below are dependent upon both the computations provided by the reference web site and by accuracy of recording of the time of observations. The calculations use tenths of hours. The Sun Distance needs to be captured at the moment the time increments to a given tenth.

Note on data below: The figure quoted after distance is a rate of progress along the orbital path [exact meaning to be determined]
Minus prefix means Mars is approaching the Sun. Plus prefix means Mars is moving away from the Sun.
The figure computed to the right of "Difference" is the rate of change of the distance to Sun. Increasing to Aphelion/Decreasing to Perihelion.

Aphelion of Mars is due March 04, 2027 Sol 151-152 Note velocity of Mars was 22.0 km/s nearing Aphelion (21.97 km/s)
Perhelion of Mars is due May, 2028 Sol 251 Note velocity of Mars was 26.5 km/s nearing Perihelion 2026/03/26
Mars passed through 0 Radial Distance on outbound leg Sol 633 of Year 38 2026/08/25 Solar Longitude is 341.1 (90 degrees season)
Mars will pass through 0 Radial Distance on inbound leg Sol 219 at longitude 71 270 degrees seasonal)
Conversion between seasons and physical frameworks: L_s = theta + 251 theta = L_s - 251

===
Distance: Mars >> Sun per theskylive.com: 232,833,829 km [23.6 km/s] Difference is +185850 <= +7744 km/hour at 12.0 on 09/29 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 232,647,979 km [23.6 km/s] Difference is +186351 <= +7765 km/hour at 12.0 on 09/28 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 232,461,628 km [23.7 km/s] Difference is +186764 <= +7782 km/hour at 12.0 on 09/27 (time 12:00) (24.0 hours)
>13

Velocity along the orbit is NOT the same thing as velocity change of the radial distance to the Sun. Both are shown in the section above.
Observation: The sky view is ** filled ** with objects and some have been recorded and given identification by humans or their robot assistants
And! ** All ** the location assignments are from the perspective of Earth. The entire catalog needs to be adjusted when inter-stellar travel begins
The work that lies ahead for the astronomical community is daunting - there is work ahead for centuries
2022/01/19 - All current (existing) stellar catalogs are computed with reference to the Earth. Another civilization would use it's planet as reference.
Perhaps a Milky Way frame of reference will become necessary at some point. The Earth is as good a Zero point as any, for humans.

=== Mars is in Regular movement as seen from Earth.
Mars is in Gemini – we in NewMars have an opportunity to visit some of the stars in Gemini during this period
Next ahead: Galaxy below 11 hours marker PGC 1638136 RA 8h 12m 48.1s
Galaxy in path PGC 1641594 RA 8h 11m 7.6s Day 2 at 5.5 hours marker
14>

Zoom Out Capability As a general observation ... I've become increasingly interested in knowing what the larger view of the sky might be like.
The site: theskylive.com does a terrific job of matching the view from Earth towards Mars, against a background of actual astronomical plates.
I wish there were a way (or rather, I wish I ** knew ** about a way that may exist) to enlarge the view until the entire galaxy is in view (Zoom out)
Update 2022/12/08 TheSkyLive.com provides a large view of selected objects: Select [Major Bodies] Then select [Information] in the body of interest
Update 2022/12/08 Scroll down to (body) Position and Finder Charts. Field of view is 50x30 degrees.

Light travel in one second is (about) 300,000 kilometers. The distance covered in one minute is about 18,000,000 kilometers. Estimated light times:
1:18,2:36,3:54,4:72,5:90,6:108,7:126,8:144,9:162,10:180,11:198,12:216,13:234,14:252,15:270,16:288,17:306,18:324, 19:342,20:360,21:378,22:396

Light travel time today is between 14 and 15 minutes. Communications delay would be 28+ minutes round trip.

=== Time estimate will change below 252 megaKm
Earth Distance in km: 2026/09/29 250,674,256 (decreasing)
Earth Distance in km: 2026/09/28 251,684,628 (decreasing)
Earth Distance in km: 2026/09/27 252,687,992 (decreasing)
>15

Maximum Earth-Mars distance is estimated to be 401 million kilometers (both at apogee and opposite vs Sun) Minimum is about 56 million kilometers
Mars and Earth were in Opposition (Earth center) in December of 2022. The date coincided with a (very rare) occultation of Mars by the Moon.
Mars and Earth were in Conjunction (Sun center) in November of 2023.
Mars and Earth appear to have been as close as they will get in Year 36. 81,454,323 kilometers on J0036644 Time: 4.53 minutes - 9 minutes round trip

In his online interview with Dr. Zubrin at the 2020 Mars Conference, Elon Musk reminded the audience that communications with Mars will necessarily include an intermediary station to handle traffic when the Sun is between Mars and Earth. Communications delays in that circumstance will increase due to the extra distance to be covered. Mr. Musk indicated he expects such communication will be handled by laser. Location would be optimum at poles of solar plane.

This web site offers an online model of the solar system: www.solarsystemscope.com
This web site offers an online orrery view of the Solar System: https://www.theplanetstoday.com/

===
Sol 667 is in Month 24 of a Proposed 24 month calendar. See Post 19 of Holidays topic for a summary. <<< 595 is skip day on Mars
Month 24 extends from Sol 642 through 688. <<== There are 27 days in Month 23. See post 82 of Holidays topic for current details
Direct path to source: http://newmars.com/forums/viewtopic.php … 57#p154257
Sol 667 is Thursday in the Proposed Business calendar for Mars. Sol 667 Skip Day on Mars. Next is near 37 of Year 389
##

The Next New Year's on Mars will occur when Solar Longitude reaches 360 degrees. Year 38 started November 12, 2024 on Earth
Per www.planetary.org Year 36 started 2021/02/07 on Earth. Mars Year 37 began 2022/12/27 on Earth.

Days of the Week Alignment:
Days of the week fall behind Earth due to the longer Sol, but they also change when Friday is omitted at the end of a Quarter
337 Earth days were observed to elapse in the 2020 weekday cycle. There were 7 week day transitions and 2 Quarter ends.
The next cycle began on the first Sol of the period of coincidence. The alignment of weekdays interval is in the range: (310 - 337)
To find the first day of a period of coincidence: Set up: SearchTerm(colon) and (colon)Alignment and J0036* or J0037*
The most recent End-Of-Quarter change occurred: … The search specified above gave 11 pages of results.

For current weather on Mars see:

***https://mars.nasa.gov/insight/weather/***
***Insight's weather info has been suspended and now is directing to msl*** <<-- Insight's mission is over (2022)

https://mars.nasa.gov/msl/weather/

Per SpaceNut: Here is another web page by NASA containing the latest news releases

https://mars.nasa.gov/news/?page=0&per_ … ope=Latest

All forum members are invited to post significant events for this day.
Events of interest will be ON Mars, or relate to Mars. Examples are launches, landings, discoveries

Standard Month in Mars Business Calendar Copyright ® 2023 NewMars.com Mars Society
Su Mo Tu We Th Fr Sa
1    2    3    4    5    6    7
8    9 10    11 12 13 14
15 16 17    18 19 20 21
22 23 24    25 26 27 28

Recruiting text may be found at the bottom of this post: http://newmars.com/forums/viewtopic.php … 57#p154257
Copyright the Mars Society All Rights Reserved

Month 24 of 24: Last month of Quarter 4 and Last month of Mars year 38

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#3884 2026-09-30 06:02:06

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

Place holder for today's Calendar update
[51.4792N, 0.0000E] 09/30/2026, 13:00:00 Europe/London
Object: Mars [open sky map]
RA 08h 15m 27.9s Dec +20° 49' 35.6" Appar J2000
Mag: 1.09 (Estimated: JPL) Const: Cancer

Sun Dist: 233,019,088 km [23.6 km/s] Km Mi
Earth Dist: 249,657,254 km [31.7 km/s]

Martian Year:
38
Martian Astronomical Month:
12
Solar longitude Ls:
359.7
Sol number:
668

Current ID: 241801
Total number of registered users: 19,630
Total number of topics: 9,131
Total number of posts: 237,481
Newest registered user: Redfoot-2026
Registered users online: 1
Guests online: 236
Online: tahanson43206

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#3885 2026-09-30 07:38:56

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

This post is intended to show a prototype of a possible BBCode display of the Business Calendar for Mars for Sol 1 of Year 39

Oh well! Gemini forgot how to write BBCode. This is a sample that shows HTML mixed with a bit of BBCode.

[size=130]Mars Year 39 — Business Calendar Daily Update[/size]
[hr][/hr]
[table]
[tr]
[td]Sol Number:[/td]
[td]Sol 1 of 668[/td]
[/tr]
[tr]
[td]Sol Classification:[/td]
[td]Standard Business Sol[/td]
[/tr]
[tr]
[td]MTC Start (Airy-0):[/td]
[td]2026-09-30 08:21:00 UTC[/td]
[/tr]
[tr]
[td]MTC End (Airy-0):[/td]
[td]2026-10-01 09:00:35 UTC[/td]
[/tr]
[tr]
[td]Sol Duration:[/td]
[td]24.66 Hours (24h 39m 35s)[/td]
[/tr]
[tr]
[td]Earth UTC Overlap:[/td]
[td]63.5% (2026-09-30) / 36.5% (Next Day)[/td]
[/tr]
[/table]
[hr][/hr]
Mars Business Calendar Protocol | Anchored to Airy-0 (MTC) | MY 39

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#3886 2026-09-30 07:46:46

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

In this post, Gemini will try again:
How FluxBB Renders It on NewMars:

Mars Year 39 -- Business Calendar Daily Update

Sol Number: Sol 1 of 668
Sol Classification: Standard Business Sol
MTC Start (Airy-0): 2026-09-30 08:21:00 UTC
MTC End (Airy-0): 2026-10-01 09:00:35 UTC
Sol Duration: 24.66 Hours (24h 39m 35s)
Earth UTC Overlap: 63.5% (2026-09-30) / 36.5% (Next Day)

Mars Business Calendar Protocol | Anchored to Airy-0 (MTC) | MY 39

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#3887 2026-09-30 07:59:28

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

In this post, Gemini shows what the daily entry would look like if we add a table of holidays to the system:

Mars Year 39 -- Business Calendar Daily Update

Sol Number: Sol 1 of 668
Sol Classification: NEW YEAR'S DAY HOLIDAY (Mars Year Launch)
MTC Start (Airy-0): 2026-09-30 08:21:00 UTC
MTC End (Airy-0): 2026-10-01 09:00:35 UTC
Sol Duration: 24.66 Hours (24h 39m 35s)
Earth UTC Overlap: 63.5% (2026-09-30) / 36.5% (Next Day)

Mars Business Calendar Protocol | Anchored to Airy-0 (MTC) | MY 39

Image for possible Calendar: Midnight at Airy Crater between Year 38 and 39

file.php?id=144

Orion is the Constellation of the Month for Month 1 of Year 39 of the Business Calendar for Mars
Orion is visible in the skyscape above at right center.
As discovered by ChatGPT, using NASA online resources, the line between the center of Mars and Airy Crater and the Sun, passes through Orion at midnight between years 38 and 39.

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#3888 2026-09-30 12:32:44

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

===
Today on Mars: 0038/24/27 Saturday Days of the week OFFSET 4 with Earth. (count from Mars to Earth )
Sol 668 Business Month 24 Sixth month of Quarter 4 of Year 38
Today on Earth: 2026/09/30 Wednesday Earth Date) End of Quarter offsets Skip Day.
>16

To see how this calendar works, we show the standard 28 day month at the bottom of this daily report.
There are 20 months of 28 Sols and 4 months of 27 Sols at the end of the four six-month quarters.
New Years Eve is extended to align the Business Calendar for Mars with the Astronomical calendar.
Business and Astronomical both start at zero (to the nanosecond) on New Year's Day.
This calendar has been in operation for two full Mars years (36 and 37). We are in Year 38

This calendar is NOT the Darian Calendar!

Per http://www-mars.lmd.jussieu.fr/mars/tim … _time.html also see: in-the-sky.org for opposition/perigee/aphelion

Martian Year: 38 Martian Astronomical Interval in 12 interval format: 12 <<== The Astronomical interval
Check Longitude: the interval will increment when longitude reaches 360 degrees

===
Solar Longitude: 359.7 Sol Number: 668 Change in degrees is +.5 Julian date is: J0038668 << Extended day 1.6 Sols >>
Solar Longitude: 359.2 Sol Number: 667 Change in degrees is +.5 Julian date is: J0038667 << Skip day on Mars
Solar Longitude: 358.7 Sol Number: 667 Change in degrees is +.5 Julian date is: J0038667
#7>

Note that Solar Longitude measurement varies as a function of location in orbit. Ls 0 is the moment when the Sun appears to transit from one hemisphere to the other. Update from Mars.NASA.gov (The Sun crosses the equator of Mars (Vernal Equinox)). The transition itself is a function of the tilt of an object with respect to the Solar plane. Per squarewidget.com, Hipparchus created the celestial coordinate system we use today.

Note#2: https://theskylive.com/mars-tracker This web site shows the astronomical position of Mars as seen from Earth
Todo: At next Aphelion/Perihelion record the Mars date as J00##### (and set Search term)
Perihelion occurred in 2026 at Ls 251 on Sol 486 - Earth Date 2026/03/27 Next: (estimated) 2028/05/15
Perihelion occurred in 2024 at Ls 251 on Sol 485 - Earth Date 2024/05/08 Next: (estimated) 2026/03/06 (actual) 2026/03/26
Perihelion occurred in 2022 at Ls 251 on Sol 485 - Earth Date 2022/06/21 Next: (actual) 2024/05/08
Aphelion Earth Dates: Next: 2027/03/04 Earlier: 2025/04/16, 2023/05/30, 2021/07/12, 2019/08/25, 2017/10/07, 2015/11/20
Aphelion occurred at--- Ls 071 on Sol 152.
Aphelion occurred near Ls 070 on Sol 153 (per http://www.planetary.org)

Note#3: The computations below are dependent upon both the computations provided by the reference web site and by accuracy of recording of the time of observations. The calculations use tenths of hours. The Sun Distance needs to be captured at the moment the time increments to a given tenth.

Note on data below: The figure quoted after distance is a rate of progress along the orbital path [exact meaning to be determined]
Minus prefix means Mars is approaching the Sun. Plus prefix means Mars is moving away from the Sun.
The figure computed to the right of "Difference" is the rate of change of the distance to Sun. Increasing to Aphelion/Decreasing to Perihelion.

Aphelion of Mars is due March 04, 2027 Sol 151-152 Note velocity of Mars was 22.0 km/s nearing Aphelion (21.97 km/s)
Perhelion of Mars is due May, 2028 Sol 251 Note velocity of Mars was 26.5 km/s nearing Perihelion 2026/03/26
Mars passed through 0 Radial Distance on outbound leg Sol 633 of Year 38 2026/08/25 Solar Longitude is 341.1 (90 degrees season)
Mars will pass through 0 Radial Distance on inbound leg Sol 219 at longitude 71 270 degrees seasonal)
Conversion between seasons and physical frameworks: L_s = theta + 251 theta = L_s - 251

===
Distance: Mars >> Sun per theskylive.com: 233,019,088 km [23.6 km/s] Difference is +185259 <= +7719 km/hour at 12.0 on 09/30 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 232,833,829 km [23.6 km/s] Difference is +185850 <= +7744 km/hour at 12.0 on 09/29 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 232,647,979 km [23.6 km/s] Difference is +186351 <= +7765 km/hour at 12.0 on 09/28 (time 12:00) (24.0 hours)
>13

Velocity along the orbit is NOT the same thing as velocity change of the radial distance to the Sun. Both are shown in the section above.
Observation: The sky view is ** filled ** with objects and some have been recorded and given identification by humans or their robot assistants
And! ** All ** the location assignments are from the perspective of Earth. The entire catalog needs to be adjusted when inter-stellar travel begins
The work that lies ahead for the astronomical community is daunting - there is work ahead for centuries
2022/01/19 - All current (existing) stellar catalogs are computed with reference to the Earth. Another civilization would use it's planet as reference.
Perhaps a Milky Way frame of reference will become necessary at some point. The Earth is as good a Zero point as any, for humans.

=== Mars is in Regular movement as seen from Earth.
Mars is in Gemini – we in NewMars have an opportunity to visit some of the stars in Gemini during this period
Next ahead: Star in path and well ahead: TYC 1390-1152-1 RA 8h 16m 53.8s
Galaxy below 11 hours marker PGC 1638136 RA 8h 12m 48.1s Day 2 out of view after reset
Galaxy in path PGC 1641594 RA 8h 11m 7.6s Day 2 at 5.5 hours marker Day 3 visible before reset but not after
14>

Zoom Out Capability As a general observation ... I've become increasingly interested in knowing what the larger view of the sky might be like.
The site: theskylive.com does a terrific job of matching the view from Earth towards Mars, against a background of actual astronomical plates.
I wish there were a way (or rather, I wish I ** knew ** about a way that may exist) to enlarge the view until the entire galaxy is in view (Zoom out)
Update 2022/12/08 TheSkyLive.com provides a large view of selected objects: Select [Major Bodies] Then select [Information] in the body of interest
Update 2022/12/08 Scroll down to (body) Position and Finder Charts. Field of view is 50x30 degrees.

Light travel in one second is (about) 300,000 kilometers. The distance covered in one minute is about 18,000,000 kilometers. Estimated light times:
1:18,2:36,3:54,4:72,5:90,6:108,7:126,8:144,9:162,10:180,11:198,12:216,13:234,14:252,15:270,16:288,17:306,18:324, 19:342,20:360,21:378,22:396

Light travel time today is between 14 and 15 minutes. Communications delay would be 28+ minutes round trip.

=== Time estimate will change below 252 megaKm
Earth Distance in km: 2026/09/30 249,657,254 (decreasing)
Earth Distance in km: 2026/09/29 250,674,256 (decreasing)
Earth Distance in km: 2026/09/28 251,684,628 (decreasing)
>15

Maximum Earth-Mars distance is estimated to be 401 million kilometers (both at apogee and opposite vs Sun) Minimum is about 56 million kilometers
Mars and Earth were in Opposition (Earth center) in December of 2022. The date coincided with a (very rare) occultation of Mars by the Moon.
Mars and Earth were in Conjunction (Sun center) in November of 2023.
Mars and Earth appear to have been as close as they will get in Year 36. 81,454,323 kilometers on J0036644 Time: 4.53 minutes - 9 minutes round trip

In his online interview with Dr. Zubrin at the 2020 Mars Conference, Elon Musk reminded the audience that communications with Mars will necessarily include an intermediary station to handle traffic when the Sun is between Mars and Earth. Communications delays in that circumstance will increase due to the extra distance to be covered. Mr. Musk indicated he expects such communication will be handled by laser. Location would be optimum at poles of solar plane.

This web site offers an online model of the solar system: www.solarsystemscope.com
This web site offers an online orrery view of the Solar System: https://www.theplanetstoday.com/

===
Sol 668 is in Month 24 of a Proposed 24 month calendar. See Post 19 of Holidays topic for a summary. <<< 595 is skip day on Mars
Month 24 extends from Sol 642 through 688. <<== There are 27 days in Month 23. See post 82 of Holidays topic for current details
Direct path to source: http://newmars.com/forums/viewtopic.php … 57#p154257
Sol 668 is Saturday in the Proposed Business calendar for Mars. Sol 667 Skip Day on Mars. Next is near 37 of Year 389
##

The Next New Year's on Mars will occur when Solar Longitude reaches 360 degrees. Year 38 started November 12, 2024 on Earth
Per www.planetary.org Year 36 started 2021/02/07 on Earth. Mars Year 37 began 2022/12/27 on Earth.

Days of the Week Alignment:
Days of the week fall behind Earth due to the longer Sol, but they also change when Friday is omitted at the end of a Quarter
337 Earth days were observed to elapse in the 2020 weekday cycle. There were 7 week day transitions and 2 Quarter ends.
The next cycle began on the first Sol of the period of coincidence. The alignment of weekdays interval is in the range: (310 - 337)
To find the first day of a period of coincidence: Set up: SearchTerm(colon) and (colon)Alignment and J0036* or J0037*
The most recent End-Of-Quarter change occurred: … The search specified above gave 11 pages of results.

For current weather on Mars see:

***https://mars.nasa.gov/insight/weather/***
***Insight's weather info has been suspended and now is directing to msl*** <<-- Insight's mission is over (2022)

https://mars.nasa.gov/msl/weather/

Per SpaceNut: Here is another web page by NASA containing the latest news releases

https://mars.nasa.gov/news/?page=0&per_ … ope=Latest

All forum members are invited to post significant events for this day.
Events of interest will be ON Mars, or relate to Mars. Examples are launches, landings, discoveries

Standard Month in Mars Business Calendar Copyright ® 2023 NewMars.com Mars Society
Su Mo Tu We Th Fr Sa
1    2    3    4    5    6    7
8    9 10    11 12 13 14
15 16 17    18 19 20 21
22 23 24    25 26 27 28

Recruiting text may be found at the bottom of this post: http://newmars.com/forums/viewtopic.php … 57#p154257
Copyright the Mars Society All Rights Reserved

Month 24 of 24: Last month of Quarter 4 and Last month of Mars year 38

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#3889 2026-10-01 06:06:15

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

Place Holder for today's Calendar update:

[51.4792N, 0.0000E] 10/01/2026, 13:02:30 Europe/London << late by 2.5 minutes
Object: Mars [open sky map]
RA 08h 17m 55.0s Dec +20° 42' 46.7" Appar J2000
Mag: 1.10 (Estimated: JPL) Const: Cancer

Sun Dist: 233,204,138 km [23.6 km/s] Km Mi
Earth Dist: 248,631,401 km [31.6 km/s]

Martian Year: << We are in Year 39
39
Martian Astronomical Month:
1
Solar longitude Ls:
0.2
Sol number:
1

Current ID: 241834

Total number of registered users: 19,630
Total number of topics: 9,133
Total number of posts: 237,514
Newest registered user: Redfoot-2026
Registered users online: 1
Guests online: 316
Online: tahanson43206

python3 BusinessCalendarMarsV01.py
Sol | MTC Start (Earth UTC) | MTC End (Earth UTC) | Primary Earth Date | Overlap Split
----------------------------------------------------------------------------------------
Sol 1 | 2026-09-30 09:12:00 UTC | 2026-10-01 09:51:35 UTC | 2026-09-30 | 60.0% / 40.0% << When Sol 1 begins Earth Day is 9/30
Sol 2 | 2026-10-01 09:51:35 UTC | 2026-10-02 10:31:10 UTC | 2026-10-01 | 57.3% / 42.7%
Sol 3 | 2026-10-02 10:31:10 UTC | 2026-10-03 11:10:45 UTC | 2026-10-02 | 54.7% / 45.3%
Sol 4 | 2026-10-03 11:10:45 UTC | 2026-10-04 11:50:20 UTC | 2026-10-03 | 52.0% / 48.0%
Sol 5 | 2026-10-04 11:50:20 UTC | 2026-10-05 12:29:56 UTC | 2026-10-04 | 49.3% / 50.7%

This image was prepared by Stellarium to show the sky above Airy Crater at midnight between Year 38 and Year 39

file.php?id=144

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#3890 2026-10-01 08:39:10

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

===
Today on Mars: 0039/01/01 Sunday Days of the week OFFSET 4 with Earth. (count from Mars to Earth )
Sol 001 Business Month 01 First month of Quarter 1 of Year 39
Today on Earth: 2026/10/01 Thursday
>16

To see how this calendar works, we show the standard 28 day month at the bottom of this daily report.
There are 20 months of 28 Sols and 4 months of 27 Sols at the end of the four six-month quarters.
New Years Eve is extended to align the Business Calendar for Mars with the Astronomical calendar.
Business and Astronomical both start at zero (to the nanosecond) on New Year's Day.
This calendar has been in operation for two full Mars years (36 and 37). We are in Year 38

This calendar is NOT the Darian Calendar!

Per http://www-mars.lmd.jussieu.fr/mars/tim … _time.html also see: in-the-sky.org for opposition/perigee/aphelion

Martian Year: 39 Martian Astronomical Interval in 12 interval format: 1 <<== The Astronomical interval
Check Longitude: the interval will increment when longitude reaches 30 degrees

===
Solar Longitude: 000.2 Sol Number: 001 Change in degrees is +.5 Julian date is: J0039001 << First Sol of New Year
Solar Longitude: 359.7 Sol Number: 668 Change in degrees is +.5 Julian date is: J0038668 << Extended day 1.6 Sols >>
Solar Longitude: 359.2 Sol Number: 667 Change in degrees is +.5 Julian date is: J0038667 << Skip day on Mars
#7>

Note that Solar Longitude measurement varies as a function of location in orbit. Ls 0 is the moment when the Sun appears to transit from one hemisphere to the other. Update from Mars.NASA.gov (The Sun crosses the equator of Mars (Vernal Equinox)). The transition itself is a function of the tilt of an object with respect to the Solar plane. Per squarewidget.com, Hipparchus created the celestial coordinate system we use today.

Note#2: https://theskylive.com/mars-tracker This web site shows the astronomical position of Mars as seen from Earth
Todo: At next Aphelion/Perihelion record the Mars date as J00##### (and set Search term)
Perihelion occurred in 2026 at Ls 251 on Sol 486 - Earth Date 2026/03/27 Next: (estimated) 2028/05/15
Perihelion occurred in 2024 at Ls 251 on Sol 485 - Earth Date 2024/05/08 Next: (estimated) 2026/03/06 (actual) 2026/03/26
Perihelion occurred in 2022 at Ls 251 on Sol 485 - Earth Date 2022/06/21 Next: (actual) 2024/05/08
Aphelion Earth Dates: Next: 2027/03/04 Earlier: 2025/04/16, 2023/05/30, 2021/07/12, 2019/08/25, 2017/10/07, 2015/11/20
Aphelion occurred at--- Ls 071 on Sol 152.
Aphelion occurred near Ls 070 on Sol 153 (per http://www.planetary.org)

Note#3: The computations below are dependent upon both the computations provided by the reference web site and by accuracy of recording of the time of observations. The calculations use tenths of hours. The Sun Distance needs to be captured at the moment the time increments to a given tenth.

Note on data below: The figure quoted after distance is a rate of progress along the orbital path [exact meaning to be determined]
Minus prefix means Mars is approaching the Sun. Plus prefix means Mars is moving away from the Sun.
The figure computed to the right of "Difference" is the rate of change of the distance to Sun. Increasing to Aphelion/Decreasing to Perihelion.

Aphelion of Mars is due March 04, 2027 Sol 151-152 Note velocity of Mars was 22.0 km/s nearing Aphelion (21.97 km/s)
Perhelion of Mars is due May, 2028 Sol 251 Note velocity of Mars was 26.5 km/s nearing Perihelion 2026/03/26
Mars passed through 0 Radial Distance on outbound leg Sol 633 of Year 38 2026/08/25 Solar Longitude is 341.1 (90 degrees season)
Mars will pass through 0 Radial Distance on inbound leg Sol 219 at longitude 71 270 degrees seasonal)
Conversion between seasons and physical frameworks: L_s = theta + 251 theta = L_s - 251

===
Distance: Mars >> Sun per theskylive.com: 233,204,138 km [23.6 km/s] Difference is +185050 <= +7710 km/hour at 12.0 on 10/01 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 233,019,088 km [23.6 km/s] Difference is +185259 <= +7719 km/hour at 12.0 on 09/30 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 232,833,829 km [23.6 km/s] Difference is +185850 <= +7744 km/hour at 12.0 on 09/29 (time 12:00) (24.0 hours)
>13

Velocity along the orbit is NOT the same thing as velocity change of the radial distance to the Sun. Both are shown in the section above.
Observation: The sky view is ** filled ** with objects and some have been recorded and given identification by humans or their robot assistants
And! ** All ** the location assignments are from the perspective of Earth. The entire catalog needs to be adjusted when inter-stellar travel begins
The work that lies ahead for the astronomical community is daunting - there is work ahead for centuries
2022/01/19 - All current (existing) stellar catalogs are computed with reference to the Earth. Another civilization would use it's planet as reference.
Perhaps a Milky Way frame of reference will become necessary at some point. The Earth is as good a Zero point as any, for humans.

=== Mars is in Regular movement as seen from Earth.
Mars is in Gemini – we in NewMars have an opportunity to visit some of the stars in Gemini during this period
Next ahead: Galaxy on 11 hours marker PGC 1634815 RA 8h 17m 48.8s
Star in path and well ahead: TYC 1390-1152-1 RA 8h 16m 53.8s Day 2 just before Mars
14>

Zoom Out Capability As a general observation ... I've become increasingly interested in knowing what the larger view of the sky might be like.
The site: theskylive.com does a terrific job of matching the view from Earth towards Mars, against a background of actual astronomical plates.
I wish there were a way (or rather, I wish I ** knew ** about a way that may exist) to enlarge the view until the entire galaxy is in view (Zoom out)
Update 2022/12/08 TheSkyLive.com provides a large view of selected objects: Select [Major Bodies] Then select [Information] in the body of interest
Update 2022/12/08 Scroll down to (body) Position and Finder Charts. Field of view is 50x30 degrees.

Light travel in one second is (about) 300,000 kilometers. The distance covered in one minute is about 18,000,000 kilometers. Estimated light times:
1:18,2:36,3:54,4:72,5:90,6:108,7:126,8:144,9:162,10:180,11:198,12:216,13:234,14:252,15:270,16:288,17:306,18:324, 19:342,20:360,21:378,22:396

Light travel time today is between 14 and 15 minutes. Communications delay would be 28+ minutes round trip.

=== Time estimate will change below 252 megaKm
Earth Distance in km: 2026/10/01 248,631,401 (decreasing)
Earth Distance in km: 2026/09/30 249,657,254 (decreasing)
Earth Distance in km: 2026/09/29 250,674,256 (decreasing)
>15

Maximum Earth-Mars distance is estimated to be 401 million kilometers (both at apogee and opposite vs Sun) Minimum is about 56 million kilometers
Mars and Earth were in Opposition (Earth center) in December of 2022. The date coincided with a (very rare) occultation of Mars by the Moon.
Mars and Earth were in Conjunction (Sun center) in November of 2023.
Mars and Earth appear to have been as close as they will get in Year 36. 81,454,323 kilometers on J0036644 Time: 4.53 minutes - 9 minutes round trip

In his online interview with Dr. Zubrin at the 2020 Mars Conference, Elon Musk reminded the audience that communications with Mars will necessarily include an intermediary station to handle traffic when the Sun is between Mars and Earth. Communications delays in that circumstance will increase due to the extra distance to be covered. Mr. Musk indicated he expects such communication will be handled by laser. Location would be optimum at poles of solar plane.

This web site offers an online model of the solar system: www.solarsystemscope.com
This web site offers an online orrery view of the Solar System: https://www.theplanetstoday.com/

===
Sol 001 is in Month 01 of a Proposed 24 month calendar. See Post 19 of Holidays topic for a summary. <<< 37 is skip day on Mars
Month 01 extends from Sol 1 through 28. <<== There are 28 days in Month 01. See post 82 of Holidays topic for current details
Direct path to source: http://newmars.com/forums/viewtopic.php … 57#p154257
Sol 001 is Sunday in the Proposed Business calendar for Mars. Sol 667 Skip Day on Mars. Next is near 37 of Year 39
##

The Next New Year's on Mars will occur when Solar Longitude reaches 360 degrees. Year 38 started November 12, 2024 on Earth
Per www.planetary.org Year 36 started 2021/02/07 on Earth. Mars Year 37 began 2022/12/27 on Earth.

Days of the Week Alignment:
Days of the week fall behind Earth due to the longer Sol, but they also change when Friday is omitted at the end of a Quarter
337 Earth days were observed to elapse in the 2020 weekday cycle. There were 7 week day transitions and 2 Quarter ends.
The next cycle began on the first Sol of the period of coincidence. The alignment of weekdays interval is in the range: (310 - 337)
To find the first day of a period of coincidence: Set up: SearchTerm(colon) and (colon)Alignment and J0036* or J0037*
The most recent End-Of-Quarter change occurred: … The search specified above gave 11 pages of results.

For current weather on Mars see:

***https://mars.nasa.gov/insight/weather/***
***Insight's weather info has been suspended and now is directing to msl*** <<-- Insight's mission is over (2022)

https://mars.nasa.gov/msl/weather/

Per SpaceNut: Here is another web page by NASA containing the latest news releases

https://mars.nasa.gov/news/?page=0&per_ … ope=Latest

All forum members are invited to post significant events for this day.
Events of interest will be ON Mars, or relate to Mars. Examples are launches, landings, discoveries

Standard Month in Mars Business Calendar Copyright ® 2023 NewMars.com Mars Society
Su Mo Tu We Th Fr Sa
1    2    3    4    5    6    7
8    9 10    11 12 13 14
15 16 17    18 19 20 21
22 23 24    25 26 27 28

Recruiting text may be found at the bottom of this post: http://newmars.com/forums/viewtopic.php … 57#p154257
Copyright the Mars Society All Rights Reserved

Month 1 of 24: First month of Quarter 1 and first month of Mars Year 39

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#3891 2026-10-02 06:12:43

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

Place holder for today's Calendar update:

[51.4792N, 0.0000E] 10/02/2026, 13:00:05 Europe/London
Object: Mars [open sky map]
RA 08h 20m 20.6s Dec +20° 35' 53.5" Appar J2000
Mag: 1.10 (Estimated: JPL) Const: Cancer

Sun Dist: 233,387,992 km [23.6 km/s] Km Mi
Earth Dist: 247,602,089 km [31.4 km/s]

Martian Year:
39
Martian Astronomical Month:
1
Solar longitude Ls:
0.7
Sol number:
2

Current ID: 241862

Total number of registered users: 19,630
Total number of topics: 9,135
Total number of posts: 237,542
Newest registered user: Redfoot-2026
Registered users online: 1
Guests online: 338
Online: tahanson43206

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#3892 2026-10-02 07:49:00

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

===
Today on Mars: 0039/01/02 Monday Days of the week OFFSET 4 with Earth. (count from Mars to Earth )
Sol 002 Business Month 01 First month of Quarter 1 of Year 39
Today on Earth: 2026/10/02 Friday
>16

To see how this calendar works, we show the standard 28 day month at the bottom of this daily report.
There are 20 months of 28 Sols and 4 months of 27 Sols at the end of the four six-month quarters.
New Years Eve is extended to align the Business Calendar for Mars with the Astronomical calendar.
Business and Astronomical both start at zero (to the nanosecond) on New Year's Day.
This calendar has been in operation for two full Mars years (36 and 37). We are in Year 38

This calendar is NOT the Darian Calendar!

Per http://www-mars.lmd.jussieu.fr/mars/tim … _time.html also see: in-the-sky.org for opposition/perigee/aphelion

Martian Year: 39 Martian Astronomical Interval in 12 interval format: 1 <<== The Astronomical interval
Check Longitude: the interval will increment when longitude reaches 30 degrees

===
Solar Longitude: 000.7 Sol Number: 002 Change in degrees is +.5 Julian date is: J0039002
Solar Longitude: 000.2 Sol Number: 001 Change in degrees is +.5 Julian date is: J0039001 << First Sol of New Year
Solar Longitude: 359.7 Sol Number: 668 Change in degrees is +.5 Julian date is: J0038668 << Extended day 1.6 Sols >>
#6>

Note that Solar Longitude measurement varies as a function of location in orbit. Ls 0 is the moment when the Sun appears to transit from one hemisphere to the other. Update from Mars.NASA.gov (The Sun crosses the equator of Mars (Vernal Equinox)). The transition itself is a function of the tilt of an object with respect to the Solar plane. Per squarewidget.com, Hipparchus created the celestial coordinate system we use today.

Note#2: https://theskylive.com/mars-tracker This web site shows the astronomical position of Mars as seen from Earth
Todo: At next Aphelion/Perihelion record the Mars date as J00##### (and set Search term)
Perihelion occurred in 2026 at Ls 251 on Sol 486 - Earth Date 2026/03/27 Next: (estimated) 2028/05/15
Perihelion occurred in 2024 at Ls 251 on Sol 485 - Earth Date 2024/05/08 Next: (estimated) 2026/03/06 (actual) 2026/03/26
Perihelion occurred in 2022 at Ls 251 on Sol 485 - Earth Date 2022/06/21 Next: (actual) 2024/05/08
Aphelion Earth Dates: Next: 2027/03/04 Earlier: 2025/04/16, 2023/05/30, 2021/07/12, 2019/08/25, 2017/10/07, 2015/11/20
Aphelion occurred at--- Ls 071 on Sol 152.
Aphelion occurred near Ls 070 on Sol 153 (per http://www.planetary.org)

Note#3: The computations below are dependent upon both the computations provided by the reference web site and by accuracy of recording of the time of observations. The calculations use tenths of hours. The Sun Distance needs to be captured at the moment the time increments to a given tenth.

Note on data below: The figure quoted after distance is a rate of progress along the orbital path [exact meaning to be determined]
Minus prefix means Mars is approaching the Sun. Plus prefix means Mars is moving away from the Sun.
The figure computed to the right of "Difference" is the rate of change of the distance to Sun. Increasing to Aphelion/Decreasing to Perihelion.

Aphelion of Mars is due March 04, 2027 Sol 151-152 Note velocity of Mars was 22.0 km/s nearing Aphelion (21.97 km/s)
Perhelion of Mars is due May, 2028 Sol 251 Note velocity of Mars was 26.5 km/s nearing Perihelion 2026/03/26
Mars passed through 0 Radial Distance on outbound leg Sol 633 of Year 38 2026/08/25 Solar Longitude is 341.1 (90 degrees season)
Mars will pass through 0 Radial Distance on inbound leg Sol 219 at longitude 71 270 degrees seasonal)
Conversion between seasons and physical frameworks: L_s = theta + 251 theta = L_s - 251

===
Distance: Mars >> Sun per theskylive.com: 233,387,992 km [23.6 km/s] Difference is +183854 <= +7661 km/hour at 12.0 on 10/02 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 233,204,138 km [23.6 km/s] Difference is +185050 <= +7710 km/hour at 12.0 on 10/01 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 233,019,088 km [23.6 km/s] Difference is +185259 <= +7719 km/hour at 12.0 on 09/30 (time 12:00) (24.0 hours)
>13

Velocity along the orbit is NOT the same thing as velocity change of the radial distance to the Sun. Both are shown in the section above.
Observation: The sky view is ** filled ** with objects and some have been recorded and given identification by humans or their robot assistants
And! ** All ** the location assignments are from the perspective of Earth. The entire catalog needs to be adjusted when inter-stellar travel begins
The work that lies ahead for the astronomical community is daunting - there is work ahead for centuries
2022/01/19 - All current (existing) stellar catalogs are computed with reference to the Earth. Another civilization would use it's planet as reference.
Perhaps a Milky Way frame of reference will become necessary at some point. The Earth is as good a Zero point as any, for humans.

=== Mars is in Regular movement as seen from Earth.
Mars is in Gemini – we in NewMars have an opportunity to visit some of the stars in Gemini during this period
Next ahead: Galaxy below path PGC 1626483 RA 8h 20m (estimate)
Note Boomer above path: HIP 40866 RA 8h 20m 20.9s above 11 hours marker
Galaxy on 11 hours marker PGC 1634815 RA 8h 17m 48.8s Day 2 Right on 11 hours marker
Star in path and well ahead: TYC 1390-1152-1 RA 8h 16m 53.8s Day 2 just before Mars Day 3 at right edge after reset
14>

Zoom Out Capability As a general observation ... I've become increasingly interested in knowing what the larger view of the sky might be like.
The site: theskylive.com does a terrific job of matching the view from Earth towards Mars, against a background of actual astronomical plates.
I wish there were a way (or rather, I wish I ** knew ** about a way that may exist) to enlarge the view until the entire galaxy is in view (Zoom out)
Update 2022/12/08 TheSkyLive.com provides a large view of selected objects: Select [Major Bodies] Then select [Information] in the body of interest
Update 2022/12/08 Scroll down to (body) Position and Finder Charts. Field of view is 50x30 degrees.

Light travel in one second is (about) 300,000 kilometers. The distance covered in one minute is about 18,000,000 kilometers. Estimated light times:
1:18,2:36,3:54,4:72,5:90,6:108,7:126,8:144,9:162,10:180,11:198,12:216,13:234,14:252,15:270,16:288,17:306,18:324, 19:342,20:360,21:378,22:396

Light travel time today is between 14 and 15 minutes. Communications delay would be 28+ minutes round trip.

=== Time estimate will change below 252 megaKm
Earth Distance in km: 2026/10/02 247,602,089 (decreasing)
Earth Distance in km: 2026/10/01 248,631,401 (decreasing)
Earth Distance in km: 2026/09/30 249,657,254 (decreasing)
>15

Maximum Earth-Mars distance is estimated to be 401 million kilometers (both at apogee and opposite vs Sun) Minimum is about 56 million kilometers
Mars and Earth were in Opposition (Earth center) in December of 2022. The date coincided with a (very rare) occultation of Mars by the Moon.
Mars and Earth were in Conjunction (Sun center) in November of 2023.
Mars and Earth appear to have been as close as they will get in Year 36. 81,454,323 kilometers on J0036644 Time: 4.53 minutes - 9 minutes round trip

In his online interview with Dr. Zubrin at the 2020 Mars Conference, Elon Musk reminded the audience that communications with Mars will necessarily include an intermediary station to handle traffic when the Sun is between Mars and Earth. Communications delays in that circumstance will increase due to the extra distance to be covered. Mr. Musk indicated he expects such communication will be handled by laser. Location would be optimum at poles of solar plane.

This web site offers an online model of the solar system: www.solarsystemscope.com
This web site offers an online orrery view of the Solar System: https://www.theplanetstoday.com/

===
Sol 002 is in Month 01 of a Proposed 24 month calendar. See Post 19 of Holidays topic for a summary. <<< 37 is skip day on Mars
Month 01 extends from Sol 1 through 28. <<== There are 28 days in Month 01. See post 82 of Holidays topic for current details
Direct path to source: http://newmars.com/forums/viewtopic.php … 57#p154257
Sol 002 is Monday in the Proposed Business calendar for Mars. Sol 667 Skip Day on Mars. Next is near 37 of Year 39
##

The Next New Year's on Mars will occur when Solar Longitude reaches 360 degrees. Year 38 started November 12, 2024 on Earth
Per www.planetary.org Year 36 started 2021/02/07 on Earth. Mars Year 37 began 2022/12/27 on Earth.

Days of the Week Alignment:
Days of the week fall behind Earth due to the longer Sol, but they also change when Friday is omitted at the end of a Quarter
337 Earth days were observed to elapse in the 2020 weekday cycle. There were 7 week day transitions and 2 Quarter ends.
The next cycle began on the first Sol of the period of coincidence. The alignment of weekdays interval is in the range: (310 - 337)
To find the first day of a period of coincidence: Set up: SearchTerm(colon) and (colon)Alignment and J0036* or J0037*
The most recent End-Of-Quarter change occurred: … The search specified above gave 11 pages of results.

For current weather on Mars see:

***https://mars.nasa.gov/insight/weather/***
***Insight's weather info has been suspended and now is directing to msl*** <<-- Insight's mission is over (2022)

https://mars.nasa.gov/msl/weather/

Per SpaceNut: Here is another web page by NASA containing the latest news releases

https://mars.nasa.gov/news/?page=0&per_ … ope=Latest

All forum members are invited to post significant events for this day.
Events of interest will be ON Mars, or relate to Mars. Examples are launches, landings, discoveries

Standard Month in Mars Business Calendar Copyright ® 2023 NewMars.com Mars Society
Su Mo Tu We Th Fr Sa
1    2    3    4    5    6    7
8    9 10    11 12 13 14
15 16 17    18 19 20 21
22 23 24    25 26 27 28

Recruiting text may be found at the bottom of this post: http://newmars.com/forums/viewtopic.php … 57#p154257
Copyright the Mars Society All Rights Reserved

Month 1 of 24: First month of Quarter 1 and first month of Mars Year 39

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#3893 2026-10-02 08:41:32

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

AccuWeather celebrates Mars New Year!!!

https://www.accuweather.com/en/space-ne … uage=en-US

For Business
News / Astronomy
Happy New Year, Mars! Red Planet begins its 39th year
With days slightly longer than Earth’s and years nearly twice as long, the Red Planet follows a different calendar.
By Chloe Bland, AccuWeather, editorial intern
Published Oct 1, 2026 12:49 PM CDT | Updated Oct 1, 2026 12:49 PM CDT
NASA’s Psyche spacecraft flew past Mars and revealed breathtaking views of Mars’ surface.
Mars has officially begun a new year, giving space enthusiasts a reason to celebrate.
On Wednesday, Sept. 30, at exactly 4:16 a.m. EDT, the Red Planet began a new orbit around the sun, according to the European Space Agency (ESA). This marks the 39th Martian year, a counting system that began in 1955. The next new year won't occur until 2028, on Aug. 17.
There are many differences between time on Mars and Earth. One day on the Red Planet, also known as a "sol," lasts 24 hours and 39 minutes, the space agency explained. There are 688 sols in a Martian year, which is about twice as long as a year on Earth.
This composite image, from NASA Galileo and Mars Global Survey orbiters, of Earth and Mars was created to allow viewers to gain a better understanding of the relative sizes of the two planets. (Credit: NASA/JPL)
NASA/JPL
The Martian new year begins on the northern equinox, when spring begins in the north, and autumn begins in the south. The ESA noted that, like Earth, Mars also experiences the four seasons, but they are not equal in time due to the planet's elliptical orbit.
"The planet’s axial tilt causes the northern hemisphere to receive more sunlight during the northern summer and the southern hemisphere to receive more sunlight in northern winter," the ESA said. "Winter and summer come when the northern and southern hemispheres tilt away from the sun in turn."
Temperatures on the Red Planet are more extreme than those on Earth. During the summer, temperatures can reach 0 degrees Celsius (32 F) at noon but will later drop to –60 C (-76 F) at night, according to the ESA. The weather becomes even colder in the winter, with temperatures plunging to -110 C (-166 F).
Twelve orbits a day provide NASA Mars Global Surveyor MOC wide angle cameras a global snapshot of weather patterns across the planet. Here, bluish-white water ice clouds hang above the Tharsis volcanoes. (Credit: NASA/JPL/MSSS)
NASA/JPL/MSSS
Mars also experiences dust storms, primarily in the second half of its year. Experts explained that as the planet swings closer to the sun, the atmosphere heats up, which causes winds to lift small particles from the soil. The particles heat up once they are in the air and then redistribute some of the warmth to the surrounding atmosphere, a process that can "rapidly pump a lot of dust."
An animation created from photos taken 21 seconds apart from NASA's Perseverance Mars Rover on Aug. 30, 2023, showing a dust devil moving along the mountains of Mars. (NASA)
NASA Rovers have also spotted dust devils swirling across the arid landscape, similar to those that occur on Earth.
Mars is one of the easiest planets to spot in the night sky, appearing red or orange and setting itself apart from the countless stars in the sky.
The Red Planet is inhospitable to humans, but it is also the only known planet inhabited entirely by robots, NASA noted. NASA currently has four active missions at Mars gathering data, including the Perseverance and Curiosity rovers, so astronauts can eventually travel to the Martian surface.

(th)

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#3894 2026-10-03 06:01:31

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

Place holder for today's Calendar update

[51.4792N, 0.0000E] 10/03/2026, 13:00:08 Europe/London
Object: Mars [open sky map]
RA 08h 22m 46.0s Dec +20° 28' 54.3" Appar J2000
Mag: 1.10 (Estimated: JPL) Const: Cancer

Sun Dist: 233,571,582 km [23.5 km/s] Km Mi
Earth Dist: 246,564,051 km [31.2 km/s]

Martian Year:
39
Martian Astronomical Month:
1
Solar longitude Ls:
1.2
Sol number:
3

Current ID: 241903

Total number of registered users: 19,630
Total number of topics: 9,138
Total number of posts: 237,583
Newest registered user: Redfoot-2026
Registered users online: 1
Guests online: 323
Online: tahanson43206

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#3895 2026-10-03 09:53:22

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

===
Today on Mars: 0039/01/03 Tuesday Days of the week OFFSET 4 with Earth. (count from Mars to Earth )
Sol 003 Business Month 01 First month of Quarter 1 of Year 39
Today on Earth: 2026/10/03 Saturday
>16

To see how this calendar works, we show the standard 28 day month at the bottom of this daily report.
There are 20 months of 28 Sols and 4 months of 27 Sols at the end of the four six-month quarters.
New Years Eve is extended to align the Business Calendar for Mars with the Astronomical calendar.
Business and Astronomical both start at zero (to the nanosecond) on New Year's Day.
This calendar has been in operation for two full Mars years (36 and 37). We are in Year 38

This calendar is NOT the Darian Calendar!

Per http://www-mars.lmd.jussieu.fr/mars/tim … _time.html also see: in-the-sky.org for opposition/perigee/aphelion

Martian Year: 39 Martian Astronomical Interval in 12 interval format: 1 <<== The Astronomical interval
Check Longitude: the interval will increment when longitude reaches 30 degrees

===
Solar Longitude: 001.2 Sol Number: 003 Change in degrees is +.5 Julian date is: J0039003
Solar Longitude: 000.7 Sol Number: 002 Change in degrees is +.5 Julian date is: J0039002
Solar Longitude: 000.2 Sol Number: 001 Change in degrees is +.5 Julian date is: J0039001 << First Sol of New Year
#6>

Note that Solar Longitude measurement varies as a function of location in orbit. Ls 0 is the moment when the Sun appears to transit from one hemisphere to the other. Update from Mars.NASA.gov (The Sun crosses the equator of Mars (Vernal Equinox)). The transition itself is a function of the tilt of an object with respect to the Solar plane. Per squarewidget.com, Hipparchus created the celestial coordinate system we use today.

Note#2: https://theskylive.com/mars-tracker This web site shows the astronomical position of Mars as seen from Earth
Todo: At next Aphelion/Perihelion record the Mars date as J00##### (and set Search term)
Perihelion occurred in 2026 at Ls 251 on Sol 486 - Earth Date 2026/03/27 Next: (estimated) 2028/05/15
Perihelion occurred in 2024 at Ls 251 on Sol 485 - Earth Date 2024/05/08 Next: (estimated) 2026/03/06 (actual) 2026/03/26
Perihelion occurred in 2022 at Ls 251 on Sol 485 - Earth Date 2022/06/21 Next: (actual) 2024/05/08
Aphelion Earth Dates: Next: 2027/03/04 Earlier: 2025/04/16, 2023/05/30, 2021/07/12, 2019/08/25, 2017/10/07, 2015/11/20
Aphelion occurred at--- Ls 071 on Sol 152.
Aphelion occurred near Ls 070 on Sol 153 (per http://www.planetary.org)

Note#3: The computations below are dependent upon both the computations provided by the reference web site and by accuracy of recording of the time of observations. The calculations use tenths of hours. The Sun Distance needs to be captured at the moment the time increments to a given tenth.

Note on data below: The figure quoted after distance is a rate of progress along the orbital path [exact meaning to be determined]
Minus prefix means Mars is approaching the Sun. Plus prefix means Mars is moving away from the Sun.
The figure computed to the right of "Difference" is the rate of change of the distance to Sun. Increasing to Aphelion/Decreasing to Perihelion.

Aphelion of Mars is due March 04, 2027 Sol 151-152 Note velocity of Mars was 22.0 km/s nearing Aphelion (21.97 km/s)
Perhelion of Mars is due May, 2028 Sol 251 Note velocity of Mars was 26.5 km/s nearing Perihelion 2026/03/26
Mars passed through 0 Radial Distance on outbound leg Sol 633 of Year 38 2026/08/25 Solar Longitude is 341.1 (90 degrees season)
Mars will pass through 0 Radial Distance on inbound leg Sol 219 at longitude 71 270 degrees seasonal)
Conversion between seasons and physical frameworks: L_s = theta + 251 theta = L_s - 251

===
Distance: Mars >> Sun per theskylive.com: 233,571,582 km [23.5 km/s] Difference is +183590 <= +7650 km/hour at 12.0 on 10/03 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 233,387,992 km [23.6 km/s] Difference is +183854 <= +7661 km/hour at 12.0 on 10/02 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 233,204,138 km [23.6 km/s] Difference is +185050 <= +7710 km/hour at 12.0 on 10/01 (time 12:00) (24.0 hours)
>13

Velocity along the orbit is NOT the same thing as velocity change of the radial distance to the Sun. Both are shown in the section above.
Observation: The sky view is ** filled ** with objects and some have been recorded and given identification by humans or their robot assistants
And! ** All ** the location assignments are from the perspective of Earth. The entire catalog needs to be adjusted when inter-stellar travel begins
The work that lies ahead for the astronomical community is daunting - there is work ahead for centuries
2022/01/19 - All current (existing) stellar catalogs are computed with reference to the Earth. Another civilization would use it's planet as reference.
Perhaps a Milky Way frame of reference will become necessary at some point. The Earth is as good a Zero point as any, for humans.

=== Mars is in Regular movement as seen from Earth.
Mars is in Gemini – we in NewMars have an opportunity to visit some of the stars in Gemini during this period
Next ahead: Micro-Boomer above path HIP 41083 RA 8h 22m 56.5s
Galaxy below path PGC 1626483 RA 8h 20m (estimate) Day 2 below 5.5 hours marker Note RA 8h 20m 58.4s
Note Boomer above path: HIP 40866 RA 8h 20m 20.9s above 11 hours marker Day 2 upper right of view
14>

Zoom Out Capability As a general observation ... I've become increasingly interested in knowing what the larger view of the sky might be like.
The site: theskylive.com does a terrific job of matching the view from Earth towards Mars, against a background of actual astronomical plates.
I wish there were a way (or rather, I wish I ** knew ** about a way that may exist) to enlarge the view until the entire galaxy is in view (Zoom out)
Update 2022/12/08 TheSkyLive.com provides a large view of selected objects: Select [Major Bodies] Then select [Information] in the body of interest
Update 2022/12/08 Scroll down to (body) Position and Finder Charts. Field of view is 50x30 degrees.

Light travel in one second is (about) 300,000 kilometers. The distance covered in one minute is about 18,000,000 kilometers. Estimated light times:
1:18,2:36,3:54,4:72,5:90,6:108,7:126,8:144,9:162,10:180,11:198,12:216,13:234,14:252,15:270,16:288,17:306,18:324, 19:342,20:360,21:378,22:396

Light travel time today is between 14 and 15 minutes. Communications delay would be 28+ minutes round trip.

=== Time estimate will change below 252 megaKm
Earth Distance in km: 2026/10/03 246,564,051 (decreasing)
Earth Distance in km: 2026/10/02 247,602,089 (decreasing)
Earth Distance in km: 2026/10/01 248,631,401 (decreasing)
>15

Maximum Earth-Mars distance is estimated to be 401 million kilometers (both at apogee and opposite vs Sun) Minimum is about 56 million kilometers
Mars and Earth were in Opposition (Earth center) in December of 2022. The date coincided with a (very rare) occultation of Mars by the Moon.
Mars and Earth were in Conjunction (Sun center) in November of 2023.
Mars and Earth appear to have been as close as they will get in Year 36. 81,454,323 kilometers on J0036644 Time: 4.53 minutes - 9 minutes round trip

In his online interview with Dr. Zubrin at the 2020 Mars Conference, Elon Musk reminded the audience that communications with Mars will necessarily include an intermediary station to handle traffic when the Sun is between Mars and Earth. Communications delays in that circumstance will increase due to the extra distance to be covered. Mr. Musk indicated he expects such communication will be handled by laser. Location would be optimum at poles of solar plane.

This web site offers an online model of the solar system: www.solarsystemscope.com
This web site offers an online orrery view of the Solar System: https://www.theplanetstoday.com/

===
Sol 003 is in Month 01 of a Proposed 24 month calendar. See Post 19 of Holidays topic for a summary. <<< 37 is skip day on Mars
Month 01 extends from Sol 1 through 28. <<== There are 28 days in Month 01. See post 82 of Holidays topic for current details
Direct path to source: http://newmars.com/forums/viewtopic.php … 57#p154257
Sol 003 is Tuesday in the Proposed Business calendar for Mars. Sol 667 Skip Day on Mars. Next is near 37 of Year 39
##

The Next New Year's on Mars will occur when Solar Longitude reaches 360 degrees. Year 38 started November 12, 2024 on Earth
Per www.planetary.org Year 36 started 2021/02/07 on Earth. Mars Year 37 began 2022/12/27 on Earth.

Days of the Week Alignment:
Days of the week fall behind Earth due to the longer Sol, but they also change when Friday is omitted at the end of a Quarter
337 Earth days were observed to elapse in the 2020 weekday cycle. There were 7 week day transitions and 2 Quarter ends.
The next cycle began on the first Sol of the period of coincidence. The alignment of weekdays interval is in the range: (310 - 337)
To find the first day of a period of coincidence: Set up: SearchTerm(colon) and (colon)Alignment and J0036* or J0037*
The most recent End-Of-Quarter change occurred: … The search specified above gave 11 pages of results.

For current weather on Mars see:

***https://mars.nasa.gov/insight/weather/***
***Insight's weather info has been suspended and now is directing to msl*** <<-- Insight's mission is over (2022)

https://mars.nasa.gov/msl/weather/

Per SpaceNut: Here is another web page by NASA containing the latest news releases

https://mars.nasa.gov/news/?page=0&per_ … ope=Latest

All forum members are invited to post significant events for this day.
Events of interest will be ON Mars, or relate to Mars. Examples are launches, landings, discoveries

Standard Month in Mars Business Calendar Copyright ® 2023 NewMars.com Mars Society
Su Mo Tu We Th Fr Sa
1    2    3    4    5    6    7
8    9 10    11 12 13 14
15 16 17    18 19 20 21
22 23 24    25 26 27 28

Month 1 of 24: First month of Quarter 1 and first month of Mars Year 39

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#3896 2026-10-04 06:02:27

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

Place holder for today's Calendar update:

[51.4792N, 0.0000E] 10/04/2026, 13:00:00 Europe/London
Object: Mars [open sky map]
RA 08h 25m 10.8s Dec +20° 21' 50.3" Appar J2000
Mag: 1.10 (Estimated: JPL) Const: Cancer

Sun Dist: 233,754,556 km [23.5 km/s] Km Mi
Earth Dist: 245,519,175 km [31.0 km/s]

Martian Year:
39
Martian Astronomical Month:
1
Solar longitude Ls:
1.7
Sol number:
4

Current ID: 241925

Total number of registered users: 19,630
Total number of topics: 9,138
Total number of posts: 237,605
Newest registered user: Redfoot-2026
Registered users online: 1
Guests online: 291
Online: tahanson43206

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#3897 2026-10-04 09:55:46

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

===
Today on Mars: 0039/01/04 Wednesday Days of the week OFFSET 4 with Earth. (count from Mars to Earth )
Sol 004 Business Month 01 First month of Quarter 1 of Year 39
Today on Earth: 2026/10/04 Sunday
>16

To see how this calendar works, we show the standard 28 day month at the bottom of this daily report.
There are 20 months of 28 Sols and 4 months of 27 Sols at the end of the four six-month quarters.
New Years Eve is extended to align the Business Calendar for Mars with the Astronomical calendar.
Business and Astronomical both start at zero (to the nanosecond) on New Year's Day.
This calendar has been in operation for two full Mars years (36 and 37). We are in Year 38

This calendar is NOT the Darian Calendar!

Per http://www-mars.lmd.jussieu.fr/mars/tim … _time.html also see: in-the-sky.org for opposition/perigee/aphelion

Martian Year: 39 Martian Astronomical Interval in 12 interval format: 1 <<== The Astronomical interval
Check Longitude: the interval will increment when longitude reaches 30 degrees

===
Solar Longitude: 001.7 Sol Number: 004 Change in degrees is +.5 Julian date is: J0039004
Solar Longitude: 001.2 Sol Number: 003 Change in degrees is +.5 Julian date is: J0039003
Solar Longitude: 000.7 Sol Number: 002 Change in degrees is +.5 Julian date is: J0039002
#6>

Note that Solar Longitude measurement varies as a function of location in orbit. Ls 0 is the moment when the Sun appears to transit from one hemisphere to the other. Update from Mars.NASA.gov (The Sun crosses the equator of Mars (Vernal Equinox)). The transition itself is a function of the tilt of an object with respect to the Solar plane. Per squarewidget.com, Hipparchus created the celestial coordinate system we use today.

Note#2: https://theskylive.com/mars-tracker This web site shows the astronomical position of Mars as seen from Earth
Todo: At next Aphelion/Perihelion record the Mars date as J00##### (and set Search term)
Perihelion occurred in 2026 at Ls 251 on Sol 486 - Earth Date 2026/03/27 Next: (estimated) 2028/05/15
Perihelion occurred in 2024 at Ls 251 on Sol 485 - Earth Date 2024/05/08 Next: (estimated) 2026/03/06 (actual) 2026/03/26
Perihelion occurred in 2022 at Ls 251 on Sol 485 - Earth Date 2022/06/21 Next: (actual) 2024/05/08
Aphelion Earth Dates: Next: 2027/03/04 Earlier: 2025/04/16, 2023/05/30, 2021/07/12, 2019/08/25, 2017/10/07, 2015/11/20
Aphelion occurred at--- Ls 071 on Sol 152.
Aphelion occurred near Ls 070 on Sol 153 (per http://www.planetary.org)

Note#3: The computations below are dependent upon both the computations provided by the reference web site and by accuracy of recording of the time of observations. The calculations use tenths of hours. The Sun Distance needs to be captured at the moment the time increments to a given tenth.

Note on data below: The figure quoted after distance is a rate of progress along the orbital path [exact meaning to be determined]
Minus prefix means Mars is approaching the Sun. Plus prefix means Mars is moving away from the Sun.
The figure computed to the right of "Difference" is the rate of change of the distance to Sun. Increasing to Aphelion/Decreasing to Perihelion.

Aphelion of Mars is due March 04, 2027 Sol 151-152 Note velocity of Mars was 22.0 km/s nearing Aphelion (21.97 km/s)
Perhelion of Mars is due May, 2028 Sol 251 Note velocity of Mars was 26.5 km/s nearing Perihelion 2026/03/26
Mars passed through 0 Radial Distance on outbound leg Sol 633 of Year 38 2026/08/25 Solar Longitude is 341.1 (90 degrees season)
Mars will pass through 0 Radial Distance on inbound leg Sol 219 at longitude 71 270 degrees seasonal)
Conversion between seasons and physical frameworks: L_s = theta + 251 theta = L_s - 251

===
Distance: Mars >> Sun per theskylive.com: 233,754,556 km [23.5 km/s] Difference is +182974 <= +7624 km/hour at 12.0 on 10/04 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 233,571,582 km [23.5 km/s] Difference is +183590 <= +7650 km/hour at 12.0 on 10/03 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 233,387,992 km [23.6 km/s] Difference is +183854 <= +7661 km/hour at 12.0 on 10/02 (time 12:00) (24.0 hours)
>13

Velocity along the orbit is NOT the same thing as velocity change of the radial distance to the Sun. Both are shown in the section above.
Observation: The sky view is ** filled ** with objects and some have been recorded and given identification by humans or their robot assistants
And! ** All ** the location assignments are from the perspective of Earth. The entire catalog needs to be adjusted when inter-stellar travel begins
The work that lies ahead for the astronomical community is daunting - there is work ahead for centuries
2022/01/19 - All current (existing) stellar catalogs are computed with reference to the Earth. Another civilization would use it's planet as reference.
Perhaps a Milky Way frame of reference will become necessary at some point. The Earth is as good a Zero point as any, for humans.

=== Mars is in Regular movement as seen from Earth.
Mars is in cancer – we in NewMars have an opportunity to visit some of the stars in Cancer during this period
Next ahead: We are in a field of galaxies! PGC 1622204 RA 8h 26m 21.6s
Micro-Boomer above path HIP 41083 RA 8h 22m 56.5s Day 2 above 11 hours marker
14>

Zoom Out Capability As a general observation ... I've become increasingly interested in knowing what the larger view of the sky might be like.
The site: theskylive.com does a terrific job of matching the view from Earth towards Mars, against a background of actual astronomical plates.
I wish there were a way (or rather, I wish I ** knew ** about a way that may exist) to enlarge the view until the entire galaxy is in view (Zoom out)
Update 2022/12/08 TheSkyLive.com provides a large view of selected objects: Select [Major Bodies] Then select [Information] in the body of interest
Update 2022/12/08 Scroll down to (body) Position and Finder Charts. Field of view is 50x30 degrees.

Light travel in one second is (about) 300,000 kilometers. The distance covered in one minute is about 18,000,000 kilometers. Estimated light times:
1:18,2:36,3:54,4:72,5:90,6:108,7:126,8:144,9:162,10:180,11:198,12:216,13:234,14:252,15:270,16:288,17:306,18:324, 19:342,20:360,21:378,22:396

Light travel time today is between 14 and 15 minutes. Communications delay would be 28+ minutes round trip.

=== Time estimate will change below 252 megaKm
Earth Distance in km: 2026/10/04 245,519,175 (decreasing)
Earth Distance in km: 2026/10/03 246,564,051 (decreasing)
Earth Distance in km: 2026/10/02 247,602,089 (decreasing)
>15

Maximum Earth-Mars distance is estimated to be 401 million kilometers (both at apogee and opposite vs Sun) Minimum is about 56 million kilometers
Mars and Earth were in Opposition (Earth center) in December of 2022. The date coincided with a (very rare) occultation of Mars by the Moon.
Mars and Earth were in Conjunction (Sun center) in November of 2023.
Mars and Earth appear to have been as close as they will get in Year 36. 81,454,323 kilometers on J0036644 Time: 4.53 minutes - 9 minutes round trip

In his online interview with Dr. Zubrin at the 2020 Mars Conference, Elon Musk reminded the audience that communications with Mars will necessarily include an intermediary station to handle traffic when the Sun is between Mars and Earth. Communications delays in that circumstance will increase due to the extra distance to be covered. Mr. Musk indicated he expects such communication will be handled by laser. Location would be optimum at poles of solar plane.

This web site offers an online model of the solar system: www.solarsystemscope.com
This web site offers an online orrery view of the Solar System: https://www.theplanetstoday.com/

===
Sol 004 is in Month 01 of a Proposed 24 month calendar. See Post 19 of Holidays topic for a summary. <<< 37 is skip day on Mars
Month 01 extends from Sol 1 through 28. <<== There are 28 days in Month 01. See post 82 of Holidays topic for current details
Direct path to source: http://newmars.com/forums/viewtopic.php … 57#p154257
Sol 004 is Wednesday in the Proposed Business calendar for Mars. Sol 667 Skip Day on Mars. Next is near 37 of Year 39
##

The Next New Year's on Mars will occur when Solar Longitude reaches 360 degrees. Year 38 started November 12, 2024 on Earth
Per www.planetary.org Year 36 started 2021/02/07 on Earth. Mars Year 37 began 2022/12/27 on Earth.

Days of the Week Alignment:
Days of the week fall behind Earth due to the longer Sol, but they also change when Friday is omitted at the end of a Quarter
337 Earth days were observed to elapse in the 2020 weekday cycle. There were 7 week day transitions and 2 Quarter ends.
The next cycle began on the first Sol of the period of coincidence. The alignment of weekdays interval is in the range: (310 - 337)
To find the first day of a period of coincidence: Set up: SearchTerm(colon) and (colon)Alignment and J0036* or J0037*
The most recent End-Of-Quarter change occurred: … The search specified above gave 11 pages of results.

For current weather on Mars see:

***https://mars.nasa.gov/insight/weather/***
***Insight's weather info has been suspended and now is directing to msl*** <<-- Insight's mission is over (2022)

https://mars.nasa.gov/msl/weather/

Per SpaceNut: Here is another web page by NASA containing the latest news releases

https://mars.nasa.gov/news/?page=0&per_ … ope=Latest

All forum members are invited to post significant events for this day.
Events of interest will be ON Mars, or relate to Mars. Examples are launches, landings, discoveries

Standard Month in Mars Business Calendar Copyright ® 2023 NewMars.com Mars Society
Su Mo Tu We Th Fr Sa
1    2    3    4    5    6    7
8    9 10    11 12 13 14
15 16 17    18 19 20 21
22 23 24    25 26 27 28

Month 1 of 24: First month of Quarter 1 and first month of Mars Year 39

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#3898 2026-10-05 06:02:16

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

Place holder for today's Calendar update

[51.4792N, 0.0000E] 10/05/2026, 13:00:00 Europe/London
Object: Mars [open sky map]
RA 08h 27m 34.7s Dec +20° 14' 40.4" Appar J2000
Mag: 1.11 (Estimated: JPL) Const: Cancer

Sun Dist: 233,936,942 km [23.5 km/s] Km Mi
Earth Dist: 244,467,245 km [30.9 km/s]

Martian Year:
39
Martian Astronomical Month:
1
Solar longitude Ls:
2.2
Sol number:
5

Current ID: 241940

Total number of registered users: 19,630
Total number of topics: 9,138
Total number of posts: 237,620
Newest registered user: Redfoot-2026
Registered users online: 1
Guests online: 237
Online: tahanson43206

python3 BusinessCalendarMarsV02.py
Sol | MTC Start (Earth UTC) | MTC End (Earth UTC) | Primary Earth Date | Overlap Split
----------------------------------------------------------------------------------------
Sol 5 | 2026-10-04 11:50:20 UTC | 2026-10-05 12:29:56 UTC | 2026-10-04 | 49.3% / 50.7%
Sol 6 | 2026-10-05 12:29:56 UTC | 2026-10-06 13:09:31 UTC | 2026-10-05 | 46.6% / 53.4%
Sol 7 | 2026-10-06 13:09:31 UTC | 2026-10-07 13:49:06 UTC | 2026-10-06 | 44.0% / 56.0%
Sol 8 | 2026-10-07 13:49:06 UTC | 2026-10-08 14:28:41 UTC | 2026-10-07 | 41.3% / 58.7%
Sol 9 | 2026-10-08 14:28:41 UTC | 2026-10-09 15:08:17 UTC | 2026-10-08 | 38.6% / 61.4%

The calendar prediction above was prepared by Gemini in support of the Business Calendar for Mars.

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#3899 2026-10-05 11:12:16

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

This is output from Version 3 of Gemini's calculator for the Business Calendar for Mars

python3 BusinessCalendarForMarsV03.py
Mars Year 39 -- 5-Sol Rolling Forecast (Sols 6 to 10)
--- Sol 6 of 668 ---
Sol Classification: Standard Business Sol
MTC Start (Airy-0): 2026-10-05 11:38:56 UTC
MTC End (Airy-0): 2026-10-06 12:18:31 UTC
Sol Duration: 24.66 Hours (24h 39m 35s)
Earth UTC Overlap: 50.1% (2026-10-05) / 49.9% (Next Day)
--- Sol 7 of 668 ---
Sol Classification: Standard Business Sol
MTC Start (Airy-0): 2026-10-06 12:18:31 UTC
MTC End (Airy-0): 2026-10-07 12:58:06 UTC
Sol Duration: 24.66 Hours (24h 39m 35s)
Earth UTC Overlap: 47.4% (2026-10-06) / 52.6% (Next Day)
--- Sol 8 of 668 ---
Sol Classification: Standard Business Sol
MTC Start (Airy-0): 2026-10-07 12:58:06 UTC
MTC End (Airy-0): 2026-10-08 13:37:41 UTC
Sol Duration: 24.66 Hours (24h 39m 35s)
Earth UTC Overlap: 44.7% (2026-10-07) / 55.3% (Next Day)
--- Sol 9 of 668 ---
Sol Classification: Standard Business Sol
MTC Start (Airy-0): 2026-10-08 13:37:41 UTC
MTC End (Airy-0): 2026-10-09 14:17:17 UTC
Sol Duration: 24.66 Hours (24h 39m 35s)
Earth UTC Overlap: 42.1% (2026-10-08) / 57.9% (Next Day)
--- Sol 10 of 668 ---
Sol Classification: Standard Business Sol
MTC Start (Airy-0): 2026-10-09 14:17:17 UTC
MTC End (Airy-0): 2026-10-10 14:56:52 UTC
Sol Duration: 24.66 Hours (24h 39m 35s)
Earth UTC Overlap: 39.4% (2026-10-09) / 60.6% (Next Day)
Mars Business Calendar Protocol | Anchored to Airy-0 (MTC) | MY 39

ChatGt thinks the first "skip day" is due on October 24th. On that Earth day, a new Sol does not start.

From the perspective of a human on Mars, October 24th will appear as an empty cell on the calendar.

From the perspective of a human on Earth, October 24th will finish without a new Sol starting.

ChatGPT has agreed to attempt to pick up the ball from Gemini which threw in the towel.

(th)

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#3900 2026-10-05 12:18:19

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 26,184

Re: Martian Calender - I have created a martian calender...

===
Today on Mars: 0039/01/05 Thursday Days of the week OFFSET 4 with Earth. (count from Mars to Earth )
Sol 005 Business Month 01 First month of Quarter 1 of Year 39
Today on Earth: 2026/10/05 Monday
>16

To see how this calendar works, we show the standard 28 day month at the bottom of this daily report.
There are 20 months of 28 Sols and 4 months of 27 Sols at the end of the four six-month quarters.
New Years Eve is extended to align the Business Calendar for Mars with the Astronomical calendar.
Business and Astronomical both start at zero (to the nanosecond) on New Year's Day.
This calendar has been in operation for two full Mars years (36 and 37). We are in Year 38

This calendar is NOT the Darian Calendar!

Per http://www-mars.lmd.jussieu.fr/mars/tim … _time.html also see: in-the-sky.org for opposition/perigee/aphelion

Martian Year: 39 Martian Astronomical Interval in 12 interval format: 1 <<== The Astronomical interval
Check Longitude: the interval will increment when longitude reaches 30 degrees

===
Solar Longitude: 002.2 Sol Number: 005 Change in degrees is +.5 Julian date is: J0039005
Solar Longitude: 001.7 Sol Number: 004 Change in degrees is +.5 Julian date is: J0039004
Solar Longitude: 001.2 Sol Number: 003 Change in degrees is +.5 Julian date is: J0039003
#6>

Note that Solar Longitude measurement varies as a function of location in orbit. Ls 0 is the moment when the Sun appears to transit from one hemisphere to the other. Update from Mars.NASA.gov (The Sun crosses the equator of Mars (Vernal Equinox)). The transition itself is a function of the tilt of an object with respect to the Solar plane. Per squarewidget.com, Hipparchus created the celestial coordinate system we use today.

Note#2: https://theskylive.com/mars-tracker This web site shows the astronomical position of Mars as seen from Earth
Todo: At next Aphelion/Perihelion record the Mars date as J00##### (and set Search term)
Perihelion occurred in 2026 at Ls 251 on Sol 486 - Earth Date 2026/03/27 Next: (estimated) 2028/05/15
Perihelion occurred in 2024 at Ls 251 on Sol 485 - Earth Date 2024/05/08 Next: (estimated) 2026/03/06 (actual) 2026/03/26
Perihelion occurred in 2022 at Ls 251 on Sol 485 - Earth Date 2022/06/21 Next: (actual) 2024/05/08
Aphelion Earth Dates: Next: 2027/03/04 Earlier: 2025/04/16, 2023/05/30, 2021/07/12, 2019/08/25, 2017/10/07, 2015/11/20
Aphelion occurred at--- Ls 071 on Sol 152.
Aphelion occurred near Ls 070 on Sol 153 (per http://www.planetary.org)

Note#3: The computations below are dependent upon both the computations provided by the reference web site and by accuracy of recording of the time of observations. The calculations use tenths of hours. The Sun Distance needs to be captured at the moment the time increments to a given tenth.

Note on data below: The figure quoted after distance is a rate of progress along the orbital path [exact meaning to be determined]
Minus prefix means Mars is approaching the Sun. Plus prefix means Mars is moving away from the Sun.
The figure computed to the right of "Difference" is the rate of change of the distance to Sun. Increasing to Aphelion/Decreasing to Perihelion.

Aphelion of Mars is due March 04, 2027 Sol 151-152 Note velocity of Mars was 22.0 km/s nearing Aphelion (21.97 km/s)
Perhelion of Mars is due May, 2028 Sol 251 Note velocity of Mars was 26.5 km/s nearing Perihelion 2026/03/26
Mars passed through 0 Radial Distance on outbound leg Sol 633 of Year 38 2026/08/25 Solar Longitude is 341.1 (90 degrees season)
Mars will pass through 0 Radial Distance on inbound leg Sol 219 at longitude 71 270 degrees seasonal)
Conversion between seasons and physical frameworks: L_s = theta + 251 theta = L_s - 251

===
Distance: Mars >> Sun per theskylive.com: 233,936,942 km [23.5 km/s] Difference is +182386 <= +7599 km/hour at 12.0 on 10/05 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 233,754,556 km [23.5 km/s] Difference is +182974 <= +7624 km/hour at 12.0 on 10/04 (time 12:00) (24.0 hours)
Distance: Mars >> Sun per theskylive.com: 233,571,582 km [23.5 km/s] Difference is +183590 <= +7650 km/hour at 12.0 on 10/03 (time 12:00) (24.0 hours)
>13

Velocity along the orbit is NOT the same thing as velocity change of the radial distance to the Sun. Both are shown in the section above.
Observation: The sky view is ** filled ** with objects and some have been recorded and given identification by humans or their robot assistants
And! ** All ** the location assignments are from the perspective of Earth. The entire catalog needs to be adjusted when inter-stellar travel begins
The work that lies ahead for the astronomical community is daunting - there is work ahead for centuries
2022/01/19 - All current (existing) stellar catalogs are computed with reference to the Earth. Another civilization would use it's planet as reference.
Perhaps a Milky Way frame of reference will become necessary at some point. The Earth is as good a Zero point as any, for humans.

=== Mars is in Regular movement as seen from Earth.
Mars is in cancer – we in NewMars have an opportunity to visit some of the stars in Cancer during this period
Next ahead: Star in path 1387-40-1 RA 8h 28m 44.7s
We are in a field of galaxies! PGC 1622204 RA 8h 26m 21.6s Day 2 just past Mars
14>

Zoom Out Capability As a general observation ... I've become increasingly interested in knowing what the larger view of the sky might be like.
The site: theskylive.com does a terrific job of matching the view from Earth towards Mars, against a background of actual astronomical plates.
I wish there were a way (or rather, I wish I ** knew ** about a way that may exist) to enlarge the view until the entire galaxy is in view (Zoom out)
Update 2022/12/08 TheSkyLive.com provides a large view of selected objects: Select [Major Bodies] Then select [Information] in the body of interest
Update 2022/12/08 Scroll down to (body) Position and Finder Charts. Field of view is 50x30 degrees.

Light travel in one second is (about) 300,000 kilometers. The distance covered in one minute is about 18,000,000 kilometers. Estimated light times:
1:18,2:36,3:54,4:72,5:90,6:108,7:126,8:144,9:162,10:180,11:198,12:216,13:234,14:252,15:270,16:288,17:306,18:324, 19:342,20:360,21:378,22:396

Light travel time today is between 14 and 15 minutes. Communications delay would be 28+ minutes round trip.

=== Time estimate will change below 252 megaKm
Earth Distance in km: 2026/10/05 244,467,245 (decreasing)
Earth Distance in km: 2026/10/04 245,519,175 (decreasing)
Earth Distance in km: 2026/10/03 246,564,051 (decreasing)
>15

Maximum Earth-Mars distance is estimated to be 401 million kilometers (both at apogee and opposite vs Sun) Minimum is about 56 million kilometers
Mars and Earth were in Opposition (Earth center) in December of 2022. The date coincided with a (very rare) occultation of Mars by the Moon.
Mars and Earth were in Conjunction (Sun center) in November of 2023.
Mars and Earth appear to have been as close as they will get in Year 36. 81,454,323 kilometers on J0036644 Time: 4.53 minutes - 9 minutes round trip

In his online interview with Dr. Zubrin at the 2020 Mars Conference, Elon Musk reminded the audience that communications with Mars will necessarily include an intermediary station to handle traffic when the Sun is between Mars and Earth. Communications delays in that circumstance will increase due to the extra distance to be covered. Mr. Musk indicated he expects such communication will be handled by laser. Location would be optimum at poles of solar plane.

This web site offers an online model of the solar system: www.solarsystemscope.com
This web site offers an online orrery view of the Solar System: https://www.theplanetstoday.com/

===
Sol 005 is in Month 01 of a Proposed 24 month calendar. See Post 19 of Holidays topic for a summary. <<< 37 is skip day on Mars
Month 01 extends from Sol 1 through 28. <<== There are 28 days in Month 01. See post 82 of Holidays topic for current details
Direct path to source: http://newmars.com/forums/viewtopic.php … 57#p154257
Sol 005 is Thursday in the Proposed Business calendar for Mars. Sol 667 Skip Day on Mars. Next is near 37 of Year 39
##

The Next New Year's on Mars will occur when Solar Longitude reaches 360 degrees. Year 38 started November 12, 2024 on Earth
Per www.planetary.org Year 36 started 2021/02/07 on Earth. Mars Year 37 began 2022/12/27 on Earth.

Days of the Week Alignment:
Days of the week fall behind Earth due to the longer Sol, but they also change when Friday is omitted at the end of a Quarter
337 Earth days were observed to elapse in the 2020 weekday cycle. There were 7 week day transitions and 2 Quarter ends.
The next cycle began on the first Sol of the period of coincidence. The alignment of weekdays interval is in the range: (310 - 337)
To find the first day of a period of coincidence: Set up: SearchTerm(colon) and (colon)Alignment and J0036* or J0037*
The most recent End-Of-Quarter change occurred: … The search specified above gave 11 pages of results.

For current weather on Mars see:

***https://mars.nasa.gov/insight/weather/***
***Insight's weather info has been suspended and now is directing to msl*** <<-- Insight's mission is over (2022)

https://mars.nasa.gov/msl/weather/

Per SpaceNut: Here is another web page by NASA containing the latest news releases

https://mars.nasa.gov/news/?page=0&per_ … ope=Latest

All forum members are invited to post significant events for this day.
Events of interest will be ON Mars, or relate to Mars. Examples are launches, landings, discoveries

Standard Month in Mars Business Calendar Copyright ® 2023 NewMars.com Mars Society
Su Mo Tu We Th Fr Sa
1    2    3    4    5    6    7
8    9 10    11 12 13 14
15 16 17    18 19 20 21
22 23 24    25 26 27 28

Month 1 of 24: First month of Quarter 1 and first month of Mars Year 39

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Announcement

#3876 2026-09-27 12:31:06

Re: Martian Calender - I have created a martian calender...

#3877 2026-09-28 06:02:46

Re: Martian Calender - I have created a martian calender...

Sun Dist: 232,647,979 km [23.6 km/s] Km MiEarth Dist: 251,684,628 km [32.1 km/s]

Martian Year: 38Martian Astronomical Month: 12Solar longitude Ls: 358.7Sol number: 667

#3878 2026-09-28 09:44:07

Re: Martian Calender - I have created a martian calender...

#3879 2026-09-29 06:12:33

Re: Martian Calender - I have created a martian calender...

Sun Dist: 232,833,829 km [23.6 km/s] Km MiEarth Dist: 250,674,256 km [31.9 km/s]

Today is the full Sol before New Year's on Mars:

Martian Year: 38 Martian Astronomical Month: 12Solar longitude Ls: 359.2 << Advance per Sol is half a degree in this part of the orbit.Sol number: 667

#3880 2026-09-29 07:12:19

Re: Martian Calender - I have created a martian calender...

Instead, they rely on a continuous, uninterrupted day counter called the Mars Sol Date (MSD):

Continuous Ticking: MSD ticks continuously at the rate of 1 Sol = 24h 39m 35.244s.

Decimal Alignment: When Mars reaches L s =0 ∘ , the French site simply reports a decimal value for the Sol—for instance, Sol 668.35 of Mars Year 38.

Rollover: The integer Sol 669 proceeds as a normal 24-hour Sol, and Sol 0 (or Sol 1) of Mars Year 39 begins smoothly at 00:00:00 MTC (Coordinated Mars Time at the Airy-0 prime meridian), regardless of where the Sun happened to be at the exact fractional instant L s =0 ∘ occurred.

#3881 2026-09-29 07:24:30

Re: Martian Calender - I have created a martian calender...

#3882 2026-09-29 09:02:25

Re: Martian Calender - I have created a martian calender...

#3883 2026-09-29 13:51:37

Re: Martian Calender - I have created a martian calender...

#3884 2026-09-30 06:02:06

Re: Martian Calender - I have created a martian calender...

Sun Dist: 233,019,088 km [23.6 km/s] Km MiEarth Dist: 249,657,254 km [31.7 km/s]

Martian Year: 38Martian Astronomical Month: 12Solar longitude Ls: 359.7Sol number: 668

#3885 2026-09-30 07:38:56

Re: Martian Calender - I have created a martian calender...

#3886 2026-09-30 07:46:46

Re: Martian Calender - I have created a martian calender...

Mars Year 39 -- Business Calendar Daily Update

#3887 2026-09-30 07:59:28

Re: Martian Calender - I have created a martian calender...

Mars Year 39 -- Business Calendar Daily Update

#3888 2026-09-30 12:32:44

Re: Martian Calender - I have created a martian calender...

#3889 2026-10-01 06:06:15

Re: Martian Calender - I have created a martian calender...

Sun Dist: 233,204,138 km [23.6 km/s] Km MiEarth Dist: 248,631,401 km [31.6 km/s]

Martian Year: << We are in Year 3939Martian Astronomical Month: 1Solar longitude Ls: 0.2Sol number: 1

#3890 2026-10-01 08:39:10

Re: Martian Calender - I have created a martian calender...

#3891 2026-10-02 06:12:43

Re: Martian Calender - I have created a martian calender...

Sun Dist: 233,387,992 km [23.6 km/s] Km MiEarth Dist: 247,602,089 km [31.4 km/s]

Martian Year: 39Martian Astronomical Month: 1Solar longitude Ls: 0.7Sol number: 2

#3892 2026-10-02 07:49:00

Re: Martian Calender - I have created a martian calender...

#3893 2026-10-02 08:41:32

Re: Martian Calender - I have created a martian calender...

#3894 2026-10-03 06:01:31

Re: Martian Calender - I have created a martian calender...

Sun Dist: 233,571,582 km [23.5 km/s] Km MiEarth Dist: 246,564,051 km [31.2 km/s]

Martian Year: 39Martian Astronomical Month: 1Solar longitude Ls: 1.2Sol number: 3

#3895 2026-10-03 09:53:22

Re: Martian Calender - I have created a martian calender...

#3896 2026-10-04 06:02:27

Re: Martian Calender - I have created a martian calender...

Sun Dist: 233,754,556 km [23.5 km/s] Km MiEarth Dist: 245,519,175 km [31.0 km/s]

Martian Year: 39Martian Astronomical Month: 1Solar longitude Ls: 1.7Sol number: 4

#3897 2026-10-04 09:55:46

Re: Martian Calender - I have created a martian calender...

#3898 2026-10-05 06:02:16

Re: Martian Calender - I have created a martian calender...

Sun Dist: 233,936,942 km [23.5 km/s] Km MiEarth Dist: 244,467,245 km [30.9 km/s]

Martian Year: 39Martian Astronomical Month: 1Solar longitude Ls: 2.2Sol number: 5

#3899 2026-10-05 11:12:16

Re: Martian Calender - I have created a martian calender...

Mars Year 39 -- 5-Sol Rolling Forecast (Sols 6 to 10)

#3900 2026-10-05 12:18:19

Re: Martian Calender - I have created a martian calender...

Board footer

Sun Dist: 232,647,979 km [23.6 km/s] Km Mi
Earth Dist: 251,684,628 km [32.1 km/s]

Martian Year:
38
Martian Astronomical Month:
12
Solar longitude Ls:
358.7
Sol number:
667

Sun Dist: 232,833,829 km [23.6 km/s] Km Mi
Earth Dist: 250,674,256 km [31.9 km/s]

Martian Year:
38
Martian Astronomical Month:
12
Solar longitude Ls:
359.2 << Advance per Sol is half a degree in this part of the orbit.
Sol number:
667

Sun Dist: 233,019,088 km [23.6 km/s] Km Mi
Earth Dist: 249,657,254 km [31.7 km/s]

Martian Year:
38
Martian Astronomical Month:
12
Solar longitude Ls:
359.7
Sol number:
668

Sun Dist: 233,204,138 km [23.6 km/s] Km Mi
Earth Dist: 248,631,401 km [31.6 km/s]

Martian Year: << We are in Year 39
39
Martian Astronomical Month:
1
Solar longitude Ls:
0.2
Sol number:
1

Sun Dist: 233,387,992 km [23.6 km/s] Km Mi
Earth Dist: 247,602,089 km [31.4 km/s]

Martian Year:
39
Martian Astronomical Month:
1
Solar longitude Ls:
0.7
Sol number:
2

Sun Dist: 233,571,582 km [23.5 km/s] Km Mi
Earth Dist: 246,564,051 km [31.2 km/s]

Martian Year:
39
Martian Astronomical Month:
1
Solar longitude Ls:
1.2
Sol number:
3

Sun Dist: 233,754,556 km [23.5 km/s] Km Mi
Earth Dist: 245,519,175 km [31.0 km/s]

Martian Year:
39
Martian Astronomical Month:
1
Solar longitude Ls:
1.7
Sol number:
4

Sun Dist: 233,936,942 km [23.5 km/s] Km Mi
Earth Dist: 244,467,245 km [30.9 km/s]

Martian Year:
39
Martian Astronomical Month:
1
Solar longitude Ls:
2.2
Sol number:
5