New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: As a reader of NewMars forum, we have opportunities for you to assist with technical discussions in several initiatives underway. NewMars needs volunteers with appropriate education, skills, talent, motivation and generosity of spirit as a highly valued member. Write to newmarsmember * gmail.com to tell us about your ability's to help contribute to NewMars and become a registered member.

#1 2004-06-01 22:37:15

Dook
Banned
From: USA
Registered: 2004-01-09
Posts: 1,409

Re: HST and James Webb

If the Hubble is still in orbit and operational when the James Webb space telescope is launched won't the combined visuals be more than the two telescopes total mirror area?  Kind of like the very large array, having many telescopes in a Y pattern makes it seem like one giant telescope with a diameter of the array.

Offline

#2 2004-06-01 22:59:41

Euler
Member
From: Corvallis, OR
Registered: 2003-02-06
Posts: 922

Re: HST and James Webb

Turn Hubble and James Webb into an interferometer?  It is not that easy to do.  Light from the two telescopes needs to be combined very carefully, and the distance between them must be closely controlled (to within a fraction of the wavelength of light in which they are observing).  We have only had the ability to create interferometers in the optical spectrum for the last couple years, and we would not be able to create a space based interferometer without careful planning.

Offline

#3 2004-06-02 07:43:38

Dook
Banned
From: USA
Registered: 2004-01-09
Posts: 1,409

Re: HST and James Webb

What if you connected the two with some kind of frame that would hold them exactly in place? 

Also, how much more resolution would this give?  Would it be worth the effort?

An even more insane idea would be to combine all the light information from all the telescopes on earth and in space into one.  The resolution would be equal to a telescope larger than the earth in size.  We might be able to read license plates on cars on other planets.

Just found this:
The resolution of an interferometer approaches that of a telescope of diameter equal to the largest separation between its individual elements (telescopes).

Why aren't we doing this now?

Offline

#4 2004-06-02 23:23:26

Euler
Member
From: Corvallis, OR
Registered: 2003-02-06
Posts: 922

Re: HST and James Webb

Arrays of radio telescopes have been working as interferometers for many years.  Technical problems have prevented optical interferometers from working on Earth until recently.  Currently, the twin 10-meter Keck telescopes are able to work as an interferometer, and the 4 8.2 meter telescopes of the new Very Large Telescope are designed to work together as interferometers.  When operating in full interferometer mode, the VLT is expected to have an angular resolution of .001 arcseconds.  This should be more than sufficient to spot the Apollo landers on the moon.  There are some plans to eventually build a space based interferometer, though for it to work it will have to be designed to work as an interferometer, and not simply be a bunch of random telescopes thrown together.

It is important to note the limitations of interferometers.  While they can get much better resolution, they cannot increase the light gathering power of the telescopes by the same amount.  So while the pictures will be clearer, they will not be able to make dim objects brighter.  Also, interferometers can only look at one area at a time, which means that a large number of telescopes operating independently would still be better for many applications.

Offline

#5 2004-06-03 08:31:15

Dook
Banned
From: USA
Registered: 2004-01-09
Posts: 1,409

Re: HST and James Webb

Why can't they combine the visuals from Keck, VLT, and hubble into one?  Use them all as one big interferometer.

Offline

#6 2004-06-03 11:02:40

Euler
Member
From: Corvallis, OR
Registered: 2003-02-06
Posts: 922

Re: HST and James Webb

They don't just combine pictures from different telescopes to form an interferometer, they actually combine the light itself.  Generally this is accomplished by running fiber optic cables from the telescopes to a beam combiner that mergers the light from the different telescopes.  This is where the technical challenges come in, if the length of the cables connecting the telescopes is off by even a few hundred nanometers, the signals won't combine properly and the interferometer won't work.

Offline

#7 2004-06-03 11:15:08

Dook
Banned
From: USA
Registered: 2004-01-09
Posts: 1,409

Re: HST and James Webb

Couldn't you use a nuclear clock to tell each telescope to take a picture of the same object at the same time.  Any telescope that is closer would take it's picture a second or two sooner.  Actually, a better way would be to make a movie of an object with a time index then a computer program could use the time index to put all of these movies together into a single movie of the object.  The resolution would be incredible.

Offline

#8 2004-06-03 11:35:55

Euler
Member
From: Corvallis, OR
Registered: 2003-02-06
Posts: 922

Re: HST and James Webb

That might work, I am not really an expert on interferometers so it is hard to be sure.  I am sure that it would be very difficult though.  If it were easy, astronomers would already be doing it.

Offline

#9 2004-06-03 12:23:45

Euler
Member
From: Corvallis, OR
Registered: 2003-02-06
Posts: 922

Re: HST and James Webb

It turns out that atomic clocks are not precise enough for this to work.  The wavelengths of light that you are dealing have a frequency of over 10^14 hertz, while the atomic oscillations that clocks use have a frequency of less than 10^10 hertz.

Offline

#10 2004-06-03 14:55:54

Dook
Banned
From: USA
Registered: 2004-01-09
Posts: 1,409

Re: HST and James Webb

Hmm, it seems to me that you could still do it.  When the images are combined so as to be most accurate the resolution of an object would be the best.  Lets say you have a series of images all from the same time frame, as close as an atomic clock will get you.  You could post a hubble image on a computer screen then combine an image from Keck onto it and scroll through the Keck images forward or backward, each image still combining with the hubble, until it creates the best resolution.  Then they would be perfectly in time.  I kind of think there already is some kind of program like this in use by hollywood but I'm afraid I don't have any specifics at the moment.

Offline

#11 2004-06-03 20:05:13

flashgordon
Member
Registered: 2003-01-21
Posts: 314

Re: HST and James Webb

i know that astronomers fought for the Hubble space telescope even though the James Webb was going up because they want to be able to compare data at the same time (i forgot the technical ways of saying these things)

As for optical interferometers, they've had plans for those on the dark side of the moon forever; but, that type of thing is going to take a full scale space activity to get up there.

It's looking more and more that space activities just are not going to happen till nanotech comes in; or in other words, molecular manufacturing will come long before anybody gets to mars the old fashion way.

Offline

#12 2018-01-10 21:42:10

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

With the delays and cost over run those scientist are sure glad now that they did keep Hubble flying longer.....

Offline

#13 2018-01-10 21:59:19

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

I tried to find the original topics but I guess its gone the great crash.

NASA's James Webb Space Telescope passes critical milestone

$8.8 billion James Webb Space Telescope has completed critical end-to-end testing in a giant vacuum chamber at the Johnson Space Center, Scheduled for launch in the spring of 2019 aboard a European Ariane 5 rocket

011018-jwst-mirror.jpg

Offline

#14 2019-06-09 21:01:23

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

A decade plus to design and build but it may be a major on orbit device to study Mars....
How the Webb Telescope Will Explore Mars

Launching in 2021....it would have given a total view of the mars dust storm.

Offline

#15 2020-06-07 15:30:36

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

Still waiting Slide 20 for James Webb Space Telescope: due March 2021, over budget by $8.7 billion and other projects delayed and rising in cost due to corona virus....

Offline

#16 2020-11-02 21:22:50

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

NASA's Webb To Examine Objects in the Graveyard of the Solar System

kuiper-large-trans-neptunian-objects-and-satellites-hg.jpg

Seems odd that some many small planetoids have moons....

Offline

#17 2020-12-19 20:19:57

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

NASA's Webb sunshield successfully unfolds and tensions in final tests

Hopefully we will great pictures for the billions spent...

Offline

#18 2020-12-19 20:36:14

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,605

Re: HST and James Webb

For SpaceNut re #17

Thanks for this update on the Webb, and particularly on the test of the sun shield.

I note that Terraformer recently made a suggestion along these lines, in another topic.

The suggestion was offered in the context of reducing stress on metal components of space craft.

The Webb sunshield does do that, but it also provides for keeping the astronomical instruments cold so they can operate in the infrared spectrum.

I note that the responsibility for a safe launch of this expensive device has been accepted by the Europeans.  I'm guessing the American vendors who might have been considered are grateful not to have that worry on their hands.

(th)

Online

#19 2021-02-13 17:15:13

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Offline

#20 2021-04-07 19:03:23

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

This cost over run project6 may see starlight soon as the NASA Installs a Heat Shield the Size of a Tennis Court to Its Latest Telescope

To keep the telescope cold, one side of the shield will constantly be facing the Sun and the other will always be facing away. The hot side will deal with temperatures as high as 230 degrees F, while the cold side will be at around -394 F.

Offline

#21 2021-05-11 21:28:16

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

NASA and Northrop Grumman discuss the significance of mirror deployment on James Webb Space Telescope and the next steps as it prepares for launch on October 31, 2021. (May 11)

Offline

#22 2021-05-15 16:54:32

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 912

Re: HST and James Webb

NASA Completes Final Test on Webb Telescope’s Winged Mirror https://www.extremetech.com/extreme/322 … ged-mirror

Offline

#23 2021-05-31 11:00:01

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 912

Re: HST and James Webb

Hubble is still doing great work. Successor to the Hubble telescope is the James Webb Space Telescope (JWST) is scheduled to be launched in late 2021?

Hubble Tracks Down Fast Radio Bursts to Galaxies' Spiral Arms
http://spaceref.com/astronomy/hubble-tr … -arms.html

Offline

#24 2021-07-21 20:05:40

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

James Webb passes critical mission review for 2021 launch, final testing nearing completion

Artist_s_view_of_Webb_on_an_Ariane_5_rocket-1170x829.jpg


With a launch readiness date of October 31, 2021, Webb will soon be transported to French Guiana where it will be mated with its designated Ariane 5 rocket.

Following lift off from pad ELA-3 at the Guiana Space Centre, the Ariane 5 Étage Supérieur Cryotechnique (Cryogenic Upper Stage) will release JWST on a transfer orbit trajectory to the L2 Langrange point, where the telescope will perform the entirety of its mission. The L2 point is 1.5 million km away from Earth — four times the distance of the Moon from the Earth — in the direction facing away from the Sun.


The telescope will continue on the transfer orbit trajectory for four weeks before entering orbit at L2. Once at L2, the telescope will undergo a six month commissioning phase before entering full science operations.

After the telescope has been commissioned and Webb is in full science operations, it will observe the universe in the near-infrared and mid-infrared wavelengths. Near-infrared and mid-infrared are wavelengths longer than visible light, allowing JWST to see more of the universe than visible light telescopes like the Hubble Space Telescope.

Observing in the infrared is not easy, though. For Webb to observe in infrared, it will carry state-of-the-art instruments, such as specially designed cameras, spectrographs, and coronagraphs.

Webb will house four total instruments and a guidance camera in its Integrated Science Instrument Module (ISIM). These instruments are NIRCam (Near InfraRed Camera),  NIRSpec (Near InfraRed Spectrograph), MIRI (Mid-InfraRed Instrument), and FGS/NIRISS (Fine Guidance Sensor and Near-Infrared Imager and Slitless Spectrograph).

The JWST will need to stay extremely cold to achieve these infrared observations without interference — at temperatures below 50 K (−223.2 °C, or −369.7 °F). To keep its temperature cool enough to perform observations, Webb will carry a large sunshield made of silicon and aluminum-coated Kapton.

https://www.nasaspaceflight.com/tag/hubble/

Offline

#25 2021-07-25 08:23:18

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: HST and James Webb

First off this is the topic for JWTS so there is no need to start a new one under free chat as created by EdwardHeisler

Why you should believe the HYPE for the James Webb Space Telescope

Offline

Board footer

Powered by FluxBB