PDA

View Full Version : telescopes?



CzC
2002-Jun-25, 03:20 AM
i'm wanting to buy a scope for deep space objects, and maybe do some ccd imaging, budget's about $1500 for the scope. anyone have any recommendations? i have a meade 10" reflector (LXD55) back ordered, but they keep postponing shipment.

already have a celestron 6" refractor for lunar and planetary viewing, but it's like trying to lug around a comatose elephant, it is very bulky.

what do some of you have and are you happy with it?

Wally
2002-Jun-25, 01:59 PM
Sounds like you could benefit from an SCT with computer drives, such as the Meade LX200 (8, 10 and 12") or LX90 (8" only). the LX90 is right around your price range, but you could probably get a used LX200 for around that price as well if you're serious about CCD imaging. Wally

aurorae
2002-Jun-25, 09:40 PM
How necessary to you is the ability to do imaging? Really good CCD imaging of deep space objects is expensive to do as it requires a pretty high end scope and mount. This then becomes less than easily portable.

If you want a portable light bucket, I'd suggest a large truss tube dob. Later you can go with an equatorial platform if you want to try imaging with it.

Check out the bigdobs group on yahoogroups.

JimB
2002-Jun-26, 04:26 AM
Hi CzC,
I've been doing AstroPhotos for about 2 years and have used a few different systems. You can see a bunch of photos at www.telescopes-r-us.com in the "Gallery" section. Look for the ones noted "jb" or "jbarnes". Most of my images are on film with a 35mm SLR camera. I've also done videos with a digital video camera (Cannon Elura) and some digital stills (Nikon 990).

1) I've used a Meade ETX-90EC (90mm Maksutov) for some very good moon photos and some OK pictures of Jupiter & Saturn. Its good points were crisp images, excellent portability, and lots of back-focus for prime focus photos (using it like a telephoto lens). Its main drawbacks were the tripod, mount, and motors could not handle the extra weight of a camera.
Comparable new scope at today's prices: about US$850 (not including camera).

2) I've used an Criterion RV-6 (150mm reflector) for some very good Jupiter & Saturn photos. Its good points were a lot of light (6") with fast optics (f/8). Its main drawbacks were lack of portability, the tripod, mount, & motor were not precise enough for long exposures, and lack of back-focus for prime focus photos.
Compare at about US$600.

3) I've used a Celestron C-5 (127mm Schimdt-Cassigrain) on a CG-4 equatorial mount. Its good points were fair portability, the tripod could carry the scope plus camera well, it had lots of back-focus, and lots of accessories. Its drawbacks were the mount & motor were not precise enough for long exposures.
Compare at about US$900.

4) I use a TeleVue 85 (85mm apochromatic refractor) on a CG-4 mount (same as Setup 3). Its good points are fair portability and great low power (600mm focal length) photos and the tripod could carry the scope plus camera well. Its drawbacks are lack of back focus, lack of high power, and the mount & motor were not precise enough for long exposures.
Compare at about US$2200.

5) My most often used photoscope is a Celestron Ultima 2000 (200mm Schimdt-Cassigrain) on a wedge and heavy-duty tripod. Its good points are good portability, computer pointing, lots of accessories, auto & hand guiding options, lots of back-focus, lots of stability on the tripod, and excellent precision in mount and motors for long exposures. Its drawback is weaker clutches so that piggyback scopes are not an option.
Compare at about $3000. (Not including lots of helpful but not required options.)
It also has the ability to mount an SBIG ccd camera to the FRONT of the scope for low power, super fast (f/2) imaging. (I have not tried this method yet, the camera costs $1500, but I would like to someday.)


What would I recommend? As you can tell from these descriptions the tripod, mount, and motors are every bit as important as the scope, maybe more. So, maybe a smaller refractor (a 3 or 4" apo) on that tripod you already have for the 6". Is it a CG-5? That mount has a lot of potential with dual motors. By reducing the size of the scope you'll be able to carry a lot more camera gear and maybe even a second scope for guiding. There are some websites that discuss rebuilding the CG-5 into a great mount.

Off the shelf, I'd recommend concentrating on that mount instead of the telescope. I feel the NexStar 5 has some good possibilities. Its the same optical tube as Setup 4 with a fair mount, lots of flexibility, and computer pointing. Its not as heavy as the 8" on the one arm mount so it can carry a camera. Comparable at about $1200. The new NexStar 5i has a few interesting upgrades (auto guider ability).

The Orion/Vixen 102ED has great possibilities. Its a small apo on a GP mount (step above the CG-5). Compare at about $2300.

I would avoid Maksutov's unless you are only doing high power moon or planet photos.

I strongly recommend the book, "Astrophotography for the Amateur", by Covington.

Clear Skys

(edited to add the "avoid" comment)

<font size=-1>[ This Message was edited by: JimB on 2002-06-26 00:29 ]</font>

CzC
2002-Jun-26, 06:07 AM
i appreciate the advice everybody.

wally,

I called to order the LX90 at astronmics but the sales rep talked me out of it and suggested back ordering the lxd55 (10" SNT) which i did. i was surprised that a sales rep suggested that i order something else that was $800 cheaper and back ordered. either she does't work on comission or she was sincere(or maybe both).

I was hoping that the SNTs would perform nearly as well as the SCTs inch per inch of aperture, do they?

aurorae,

Never really considered dobs for imaging, im gonna look into that. Would it be a bad idea to get a 16" dob and just throw a tarp over it and leave it outside?


Jim B,

are you the JB on this web site?

http://www.telescopes-r-us.com/gallery/gallery.htm

very impressive, especially the nebulae. It's got me strongly considering SCTs, i thought (might've read it) you couldn't pull in nebulae that good with anything less than a 10" sct. Ultims 2000 is a little too expensive, though.. what other SCTs do Celestron make that has optics comparable to the ultima 2000?

thanks,
CzC

JimB
2002-Jun-26, 02:48 PM
Jim B,
are you the JB on this web site?
http://www.telescopes-r-us.com/gallery/gallery.htm
very impressive, especially the nebulae. It's got me strongly considering SCTs, i thought (might've read it) you couldn't pull in nebulae that good with anything less than a 10" sct. Ultims 2000 is a little too expensive, though.. what other SCTs do Celestron make that has optics comparable to the ultima 2000?

thanks,
CzC


Yep, that's me. Thanks for the compliment, I also created the website and help out at the store. We sell Meade, Orion, Celestron, and TeleVue products and I help people with these questions all the time. I'm not surprised Astronomics was so helpful, they're a great store.

As you can tell by my recommendations, aperture is often overrated for astrophotography -- the mount is way more important. As you increase aperture you significantly increase weight and that means the tripod/mount has to get significantly better (read costly, heavy, and bulky). Repeat with me, "It's the mount that gets great photos." A large aperture may let you get fainter objects in a shorter exposure or get you higher magnification on planets but not if the mount is shaking in the wind, vibrates every time you touch it, can't stay pointed at what you're exposing, or can't take that extra piece of equipment that would make your job easier.

With this in mind, I warn you against the LXD-55 10" SNT. I haven't seen one of these yet but that mount looks too small for a 10" SNT (which is larger than a 10" SCT), I would be worried about back-focus on any newtonian, and these things have been backordered from Christmas. I think the 6" model might be a good deal, but again I haven't seen one of these either. Many astrophotographers I know use a 4 or 5" apochromatic refractor on a Losmandy mount to get stunning images of galaxies. This is like a $10,000 investment. Frightening....

You were much closer with the LX90 8" ($1600 to 1800). Your first post mentioned portability and this scope would be excellent. A great improvement over an equatorial mount. It has a few limitations or extra items need to be purchased for some photo applications. A wedge would be needed when your exposure times get longer. Again I recommend the Celestron NexStar 5 or 5i ($1200). It really can do a lot. I see the 5i is backordered but the 5 is in stock at Astronomics. There's even a Celestar 8 for less than $1000 which used to be a standard entry astrophoto scope. As far as Celestron claims all the SCT optics get the same care and quality. If higher priced models "look better" (i.e. the view or photo thru them is better) it is because the mount gets better.

Check out Orion's astrophoto page,
www.telescope.com/cgi-bin/OrionTel.storefront/3d19caa90451fadcfe58c0a80a650703/Product/View/J000
You could start with the R200SS and add extras overtime. This is an 8" newtonian, but they have it setup for astrophoto work so I have a much higher confidence in it's back-focus. The GP and GP-DX are excellent mounts. Much better than the LXD-55 (but not computerized).

There are tons of accessories that you may need as well. Check out Lumicon or Meade's websites. Don't forget to add these to the your total expenditure. If the scopes available now were around 2 years ago I would get either the Celestron NexStar 8 GPS (~$2500 not for the GPS but for the Fastar ability and the carbon fiber tube) or the LX90 (~$1700 to save money to get more accessories).

Re: SCT image quality. It is a compromise, trading best optics for a small body. The small body means a smaller mount, smaller motor, smaller tripod, and smaller storage in the house. All of these attributes can be very important to some astrophotographers. Remember the focal length of the 8" SCT is 2030mm; a comparable refractor or reflector would be more than 6 feet long! When people give you recommendations or mention a particular scope is best, ask some sideline questions. How portable is it? How many people set it up? How often do you use it? Where do you store it? You might be surprised at the answers. Large scopes may have permanent mounts or take an entire van and three people to set up. Remember, "Aperture always wins, until you have to pick it up and take it home."

Clear Skies

aurorae
2002-Jun-26, 11:00 PM
On 2002-06-26 02:07, CzC wrote:
aurorae,

Never really considered dobs for imaging, im gonna look into that. Would it be a bad idea to get a 16" dob and just throw a tarp over it and leave it outside?



I would not recommend that. At that size, a truss would be pretty portable and not too hard to set up. If you want to use it next to your house, and never haul it anywhere, then get wheels for it.

A 16 inch solid tube dob is quite a handful. Really a 2 person scope, which is why I was suggesting a truss. But maybe with wheels you could wheel it out of the garage.

CzC
2002-Jun-27, 07:25 AM
On 2002-06-25 09:59, Wally wrote:
Sounds like you could benefit from an SCT with computer drives, such as the Meade LX200 (8, 10 and 12") or LX90 (8" only). the LX90 is right around your price range, but you could probably get a used LX200 for around that price as well if you're serious about CCD imaging. Wally




i think you and JB are right about the lx90. i'm going to get it.

thanks all,
CzC