what's the best telescope

dickbill · 2003-08-07 09:57:02

Hi all,
Nice to see the forum back. After all that time, once again, I lost the thread where it was question of telescopes, I think it was Josh who wanted to buy a Dobsonian. I create a new thread here.
Talking about telescope revived my interest, the last time I touched a telescope was... long ago, but I checked the Meade and Celestron web site and I have been amazed to see the new price range for 10" reflectors. Meade now manufactures Schmidt Newtonian telescopes on equatorial german mount, for little more than $1000, like the SN-10 LXD55.
Schmidt Newtonian is also a new concept for me, a spherical mirror instead of a parabolic ?....the focal diameter ratio is small, at f/d:4 (I used a parabolic newtonian at f/d :9 !) , the telescope is very "fast". But is it good for planet observation with a spherical mirror ? does anybody here lucky enough to have used that telescope?

Celestron plays in the same field and same price too, even cheaper actually. the C10N 10" newtonian equatorial celestron is based on a parabolic mirror at f/4.7. It's fast too. I am not sure but I think that a parabolic mirror would give better results on planets at high magnification, so while the Meade is certainly the best for wide field deep sky, the celestron might be better for planetary observation. I havn't find a comparative review.
Whatever, with 10" equatorial newtonian available at about 1000$, what people need is good sites to observe.
Does anybody know of the quality of the sky in Florida, near Miami ? isn't it too humid ?

check the telescopes at:
http://www.astronomics.com:80/main....2&vid=4

Josh Cryer · 2003-08-07 14:24:18

I confess that I can't answer this, really. I didn't get the Dobsonian, though it's still in the back of my mind.

I have read many places that scopes with equatorial mounts are superior to Dobsonian mountings when you need to do a lot of positioning and following. $849.00 for that 10" Newtonian reflector is really good!

Have you decided to get a scope dickbill? Better hurry, the epoch is soon!

dickbill · 2003-08-07 15:28:24

I have read many places that scopes with equatorial mounts are superior to Dobsonian mountings when you need to do a lot of positioning and following. $849.00 for that 10" Newtonian reflector is really good!
Have you decided to get a scope dickbill? Better hurry, the epoch is soon!

Hey Josh, sure it's good, it's even incredible I would say. Personnaly, I never had a dobsonian but no way that i could buy one, a dobsonian cannot follow the objects and you cannot make astrophoto either. While with equatorial mounting, once the station is properly set, positioning and following is a pleasure, astrophoto, CCD, everything is possible.

I cannot decide which 10" is better, the Meade Schmidt Newtonian or the Celestron newtonian. I will have to read a lot of reviews before I decide. I am just afraid that buying a 10" f/4 (or 4.7) suitable for deep sky objects does not make sense if I move to an area without a good dark sky or some montains at close proximity.
But for Mars, I don't feel in a hurry because of this august 27th closest range, after all, the following years too will be a "near" Mars situation.
If it was only for Mars, I would buy the 6" Meade refractor or a smaller apofluorite. Those give incredible image quality. We'll see.

dickbill · 2003-08-08 13:41:13

a compilation of reviews
(the Maede and Celestron 10" newtonian that I was talking about are not in this list, however, in another review, I have read that the 8" f/4 Meade is way superior to the 8" Vixen, so I infer that the 10" Meade is good quality too since it is based on the 8")

http://www.scopereviews.com/list.html

Josh Cryer · 2003-08-08 14:03:04

dickbill, thanks for reporting this, please post back here if you decide to get one.

Josh Cryer · 2003-08-09 09:22:47

Have you thought about getting an Obsession, dickbill? Those things are awesome!

http://www.globaldialog.com/~obsessiontscp/OBHP.html

I realize that tracking is an issue with Dobsonian's, but their Goto system seems to have accurate tracking ablities (or you could make your own- something I would recommend if you made your own private observatory). If you wanted a professional, yet cheap, scope, theses might be in your neighborhood.

25" scopes for 10k, amazing.

Free Spirit · 2003-08-09 10:10:42

I like dobs, you get more aperture for the buck and they are extremely simple to setup. And I find them perfectly comfortable to use. I'd only use an EQ if I was into astrophotography. As for tracking, on most deep space objects you will be using relatively low powers anyway so tracking is a non issue and I find tracking on planets isn't really much of a problem either.

Josh Cryer · 2003-08-09 10:33:07

What size scope do you have Free?

dickbill · 2003-08-09 11:23:14

Have you thought about getting an Obsession, dickbill? Those things are awesome!
http://www.globaldialog.com/~obsessiontscp/OBHP.html

It's too big for me. I will always have to put the scope in a car to find a good spot to observe.
I am also very attracted to astrophoto, I had very good results with a camera with a 200mm teleobjective in "parallele" of my 115/900, but with the Obsession, I doubt very much that such a huge monster can track effciently a star field for more than a couple of seconds.
I am very attracted to the Meade LXD55 8" or 10" (though the 10" is already too big for its mount, that's what I have read), but also in the new Celestron newtonian 10". Unfortunatly I have still to read a review for this Celestron.

dickbill · 2003-08-11 10:01:13

I am more and more confused now. The more I read the less I am sure. In addition to the Meade and Celestron 10", there is a newtonian 10" Orion, which mount (the Atlas) looks excellent, and in the same range of price.
In addition, some schmidt cassegrain that I always thought were out of range for their price are now also in the same area, just slightly more expensive. You can have now a 8" Schmidt cassegrain with an equatorial mount for about 1200$.
To add to the confusion, even 6" refractor are affordable now ! a 150 mm f/4 or 5 achromatic doublet for 900$, yes ! When you know the image quality of these refractor for planetary observation...you need to think twice before buying a refelector.
I really don't know anynmore where I'm gonna spend my 1000$. Just know that it's not gonna be a dobsonian. I want superior luminosity for astrophoto for deep sky objects AND superior resolution and contrast for planets. Any idea somebody ?

Josh Cryer · 2003-08-11 11:38:22

I dunno dickbill, those Obsession's look fantastic. I think I'm pretty much set as to which kind of scope I want now. They're extremely cost-effective for their size- yet they're also pretty portable (though you'd probably want to just build an observatory for the bigger ones). I'm just musing, though, these Obsessions are out of my league unless I got a loan out or something, and they're not in your ranger either, if you just have 1k to spend.

What kind of magnification does the 6" refractor have?

dickbill · 2003-08-11 13:34:37

I dunno dickbill, those Obsession's look fantastic. I think I'm pretty much set as to which kind of scope I want now. They're extremely cost-effective for their size- yet they're also pretty portable (though you'd probably want to just build an observatory for the bigger ones). I'm just musing, though, these Obsessions are out of my league unless I got a loan out or something, and they're not in your ranger either, if you just have 1k to spend.
What kind of magnification does the 6" refractor have?

It depends of the focal lenght of the scope and the occular (eyescope). divide one by the other.
The meade refractor LXD55 of 6" is f/8, which is (aproximately) 8X150mm=1200mm, would provide a 1200mm/4mm= 300 X magnification with a 4mm occular. That's a lot, but needed for Mars, 200 or 250 X is plenty to observe a big planet but Mars is so small.
What is striking is the price: under 1000$. That tells me that soon (in a couple of years), we can expect 8" refractor at the same price, something unthinkable 10 years ago.

Good luck with your loan Josh, but you don't have to buy the BIGGEST, Mars in a 8" reflector is fantastic already.

Josh Cryer · 2003-08-11 14:48:18

Hehe! I'm not getting a loan (yet), but I have it set so far that if I'm going to get a scope, it's going to be an Obsession. I can wait until I feel it's time to get one (I couldn't have one in time for this pass by Mars anyway).

Cindy and I were talking about scopes, as you note in this thread, and I was having a hard time deciding. Unless someone can provide a better scope (which is as cost effective), then an Obession it is!

BTW, I said in the New Dicoveries thread that I went out and saw Mars last night. I managed to see it pretty well with my little 3.5 inch reflector! Granted, I couldn't make out actual formations, but I was able to see the caps. Something I haven't been able to do. Twas good.

dickbill · 2003-08-12 08:25:19

then an Obession it is!
BTW, I said in the New Dicoveries thread that I went out and saw Mars last night. I managed to see it pretty well with my little 3.5 inch reflector! Granted, I couldn't make out actual formations, but I was able to see the caps. Something I haven't been able to do. Twas good.

Well, ultimately the biggest diameter is supposed to be the best choice, so you don't make a mistake in buying "big".

The other point, astrophoto, here again, with a huge diameter like 20 inches, long exposure requesting perfect polar alignment and pursuit for 30minutes/1 hour (photo film) or minutes (CCD), are not necessary anymore. So this invalidates a little bit my comment about the incapability of dobsonian to follow accuratly an object for several minutes, I realize that a 20" mirror must be so luminous that a CCD can probably record the object in seconds instead of minutes.
When I had my 115/900mm, a 4" newtonian of relatively good quality for the time, I had to pose Saturn for 4/5 seconds on a 400ASA film at 250X magnification, with a motor of course. Still, at that magnification 4 or 5 seconds is an eternity and I never get a really good picture. Jupiter with 2 or 3 seconds was better. So I guess that a 20' dobsonian can do it in a fraction of second with a CCD, with or without motor, bad or good alignment, it doesn't matter anymore at that speed.

So a large dobsonian cannot be a bad choice, even for astrophoto.

Palomar · 2003-08-12 08:58:24

Cindy and I were talking about scopes, as you note in this thread, and I was having a hard time deciding. Unless someone can provide a better scope (which is as cost effective), then an Obession it is!

*There's only one telescope I want: The Hubble Space Telescope!

--Cindy (yeah, I can dream...)

Josh Cryer · 2003-08-12 11:19:21

Yeah, dickbill, that's what's so great about them, you don't even need a CCD or long exposure times to see objects with the naked eye. They're, just, in your freaking face. Only problem I've seen so far is that you need to climb a ladder to use one! What'd be good is to build some sort of seat which could be moved about at ones whim, but I think something like that might be too expensive and not very portable (I believe filmmakers have such seats for their arm cameras).

Cindy, you know what? They're going to trash the Hubble like they trashed the Mir Space Station! At least, that's what they're talking about doing. What a waste. The Hubble belongs in a musuem.

clark · 2003-08-12 11:21:17

The Hubble belongs in a musuem.

So did Columbia.

NASA is refusing becuase it's not worth risking lives for.

Palomar · 2003-08-12 11:43:19

Cindy, you know what? They're going to trash the Hubble like they trashed the Mir Space Station! At least, that's what they're talking about doing. What a waste. The Hubble belongs in a musuem.

*I came across a news article relative to this a few days ago...but that article sounded vague as to what will be happening with Hubble in the near future. I hope they don't "trash" Hubble until they're very close to replacing it. Hubble has been invaluable and indispensible to astronomy.

--Cindy

dickbill · 2003-08-12 12:00:23

yes, don't trash the HST !
It could be used in the future, like, send it to the moon on the hiden face to make the first scope of a lunar ground base interferometer, after all, all it needs is a mount with rockets to land. A mount for Luna should be easy and light to design and maybe relatively cheap.
But I donno, maybe the mirror is already cripple with micrometeorites impacts and radiation.

Palomar · 2003-08-12 12:24:21

Dickbill: "yes, don't trash the HST !
It could be used in the future, like, send it to the moon on the hiden face to make the first scope of a lunar ground base interferometer, after all, all it needs is a mount with rockets to land."

*Yeah, but to get the rockets up and mounted to it would require a space shuttle mission, right? And could a shuttle carry that much weight during liftoff? And then how could you assure it would land safely on the moon, how could it be programmed to set itself up, maintained, etc.? Even if by something like "remote control"...wouldn't the fact of its being on the moon's dark side prevent us from tweaking it from here...and also prevent it from relaying information? The Apollo astronauts and Houston always lost contact when they went around the far side (I'll bet the first time around for the Apollo 8 crew gave them some goosebumps...that'd be spooky). With my limited scope of knowledge, having Hubble anywhere on the moon right now (especially the dark side of it) seems quite a tall order. If Hubble has to be maintained in orbit by shuttle crews, it'd need similar attention elsewhere, I should think. But then, what do I know? ::shrugs::

Dickbill: "But I donno, maybe the mirror is already cripple with micrometeorites impacts and radiation."

*Hmmmmm. That's another problem.

--Cindy

dickbill · 2003-08-12 13:15:17

*Yeah, but to get the rockets up and mounted to it would require a space shuttle mission, right? And could a shuttle carry that much weight during liftoff? And then how could you assure it would land safely on the moon, how could it be programmed to set itself up, maintained, etc.?

Cindy, that's probably difficult I agree, but the dark side of the moon has always been a good target for future telescope, so I guess that plans exist to land a big scope there.
Beside, what you say emphasize the lack of a heavy launcher like shuttle C, it is cruelly obvious here.
That's my european background, try to keep using the old stuff, rather than buying a brand new one. Maybe after all, refurbishing and modifying the HST and landing it on the moon would be more expensive that making a space interferometer de novo. Well, make place for the youngs !

Algol · 2003-08-25 22:30:43

The dark side of the moon only provides a bonus for radio telescopes.

Its called the 'dark side' because we never see it, rater than because light never falls on it. A lunar observatory could quite happily sit near trhe 'rim' in view of earth for transmitting data and but still having lots of sky to look at that isnt actually obstructed by the ever-present earth.

The bonus of sighting a telescope on the moon or another lareg body is that you dont need gyroscopes for it to work out what direction it is pointing in or keep it pointing in the right direction - gyroscopes simply dont last long enough and fail after a couple of years.

Algol · 2003-08-27 17:38:53

Speaking of buying telescopes, i think in about a month there will be a whol load of decent telescopes for sale on ebay.

Ranger_2833 · 2003-08-28 08:04:03

I've got an Orion SkyQuest XT 8" Dobsonian that is great. Like its been said on this thread, the only pain is the dificulty in tracking, but its low cost (about $450 new) made it well worth it. It is a great telescope for beginners (you have to know how to find the constellations) and for poor intermediates (me ). If anyone is interested, I am trying to sell it; I want to upgrade to a Maksutov and can't afford to keep both. The only real downside of a dobsonian is its size, but it think the lower price and excellent optics make up for that.

My 8" Dobsonian for Sale

Algol · 2003-08-28 11:19:08

I see youve gone for a starting bid of $500. Very sneaky

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