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C11 on an Atlas???

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#1 jmandell

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Posted 05 July 2013 - 11:34 AM

Hello to all,

I have been wanting to get into astrophotography and some variable star work and my intention was to get a c11 and an Atlas, but I think that I will probably be pushing the limits of the mount.

Would the mount handle the scope and camera well enough or should I go with something like a 9.25 or 10 inch scope?

Any other recommendations?


Thanks

#2 Raginar

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Posted 05 July 2013 - 11:39 AM

I think you're going to be pushing the mount hard. My CGEM didn't enjoy a 10" SCT on it and they're fairly similar. You'll see examples of people who say it can/should be done. My argument to you is that if you're just learning AP, start with as few variables as possible that require tight tolerances. Long focal length on a maxxed out mount is not fun.

The Atlas is well known to do better than a CGEM FWIW.

#3 orlyandico

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Posted 05 July 2013 - 11:44 AM

Use a C8 and keep your hair. :)

#4 shawnhar

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Posted 05 July 2013 - 01:01 PM

C11 is 27.5 pounds, add camera, guide scope/guide camera or off axis guider and the weight starts quickly getting close to the limit for an Atlas. Generally you will have headaches trying to image close to the weight limit and at such a long focal length. Would really need to use a focal reducer.
Getting into imaging with a 2700mm scope is what most of us would call crazy, it would be a real test of patience and determination.
Having said that, I image on a hypertuned Atlas (EQ6) with a Meade 10, it weighs 28 lbs. Don't know how much of a difference the hypertuning makes, (It was already done when I bought the mount) but I am very happy with my set up.

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#5 Jesus Munoz

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Posted 05 July 2013 - 01:24 PM

For learning astrophotography it's better you begin witha a short focal lenght telescope or lens, say 300-600 mm. When you master this FL then you can try longer FL and larger scopes. As Orlyandico said: "keep your hair".

If you already have a scope for mounting on an Atlas then keep subexposures short and try bright objects like open and globular clusters. You can get great astrophotos quickly that way.

Keep us informed.

#6 jmandell

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Posted 05 July 2013 - 02:41 PM

For learning astrophotography it's better you begin witha a short focal lenght telescope or lens, say 300-600 mm. When you master this FL then you can try longer FL and larger scopes. As Orlyandico said: "keep your hair".

If you already have a scope for mounting on an Atlas then keep subexposures short and try bright objects like open and globular clusters. You can get great astrophotos quickly that way.

Keep us informed.


I have done quite a bit of AP with a 500mm lens on an astro trac :tonofbricks:. That's a real hair pulling experience.

Thanks for the advice. I'm now looking at a c9.25 or at8rc

#7 RAKing

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Posted 05 July 2013 - 02:52 PM

The Atlas mount could handle the C11, C25, and/or AT8RC without too much trouble. The Atlas Tripod would not do as well.

When I owned my Atlas, I had an adapter made that let me use the mount on an Astro-Physics Portable Pier. A friend of mine saw this and had an adapter made so he could run his Atlas on a Losmandy HD tripod with a C11-HD Edge, plus guide scope, etc. :cool:

Either of these bases would make your Atlas suitable for imaging with those bigger scopes - but I agree with those who say that learning to image with a long focus instrument is a bad idea. :p

Cheers,

Ron

#8 Jesus Munoz

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Posted 05 July 2013 - 04:19 PM

My AP setup includes an EM-200, a C9.25 (working at f/6.3), autoguided with a 400mm FL refractor + QHY5 (PHD). I can keep 80% of the subs on good nights, and I think an OAG is a good idea for less than average nights. I work with subs around 300-900 seconds. I have seen similar results with an Atlas + C9.25.

#9 DuncanM

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Posted 05 July 2013 - 04:31 PM

My AP setup includes an EM-200, a C9.25 (working at f/6.3), autoguided with a 400mm FL refractor + QHY5 (PHD). I can keep 80% of the subs on good nights, and I think an OAG is a good idea for less than average nights. I work with subs around 300-900 seconds. I have seen similar results with an Atlas + C9.25.


There's nothing wrong with the Atlas tripod, rather, the problem is with the spreader, which is not large enough to prevent tripod twist, when the mount is heavily loaded:
http://www.sfu.ca/~dmunro/tripod.JPG
http://www.sfu.ca/~dmunro/bolts.JPG

I have since modified the standard EQ-6 tripod, by adding a plywood tray/spreader table, and added new, stainless steel, bolts to the altitude and azimuth adjusters. The above image shows these changes. The mount is now extremely stable, almost to the point of challenging my CI-700. Click on the image for a high-res version.

#10 Jesus Munoz

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Posted 05 July 2013 - 04:39 PM

Very interesting modification Duncan, adds stability and a handy table for accesories. :applause:

#11 scopefreak

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Posted 06 July 2013 - 09:44 AM

I just purchased a C11 to ride on my Atlas for AP and visual use. I have not had the chance to really try it for AP yet as the weather has been very bad here in E KY.

I will tell you that getting it to balance well in RA has not been fun. Currently I am using 4 11 lb counter weights and all of them are near the end of the bar. I ordered a longer CW shaft from CMC machine Co. in WV last week and it has not yet arrived. I am hoping that the longer shaft/bar will give me a better balance point and will allow me to use less weight. I also built a new pier for the mount/scope as the pier I was using originally was designed to be used with a C8 and was not quite big enough to support the weight of the C11.

Other then that, I am very happy with the scope/mount combo for visual. All I need now are some clear skies to test it out for AP.

BTW, I also use a reducer/corrector all the time; that makes the C11 work at f6.3. I have not looked thru the scope at its native f10 since its first light. The main reason is that I look at or image planets or the moon very rarely so a shorter FL is my preferred way to work.

The other posts in this thread are right on the mark however concerning the shorter FL scopes and beginning AP. I started out with a short tube 80 years ago when I was learning and I think this experience was priceless. Get yourself a focal reducer/corrector for what ever scope you decide on (CATS anyway) to make the scope faster at f 6.3. It was one of my best investments when I got into the world of CAT's 16 years ago.

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#12 EFT

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Posted 06 July 2013 - 11:09 AM

The quickest way to decide that you don't enjoy astrophotography will be to start learning AP with this combination. Do yourself a big favor and start with a smaller faster scope than an SCT. For practical purposes, there is little difference between the C11 and M10 since they are similar in weight. The C9.25 is a much better choice but it is still not the place to start learning AP due to it long focal length. Start with a refractor and a smaller imaging Newtonian and work your way up from there. You will be much happier in the short and long run and these scopes can be had relatively cheap.

#13 orlyandico

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Posted 06 July 2013 - 12:49 PM

I agree with Ed here. I have a C9.25 and a short refractor (AT90EDT). I use the refractor 90% of the time, even though my mount can image with the C9.25 effortlessly.

What I'm thinking of doing is adding an 8" f4 reflector. The focal length is very similar to the refractor, but it is more than one stop faster, hence shorter exposures would be needed. 8" f4 reflectors are pretty cheap, I could get three of them for the cost of my refractor.

#14 jmandell

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Posted 06 July 2013 - 06:16 PM

Thanks for all the help!

I have a dslr with lenses ranging from 14mm up to 500mm that I use with an Astrotrac, so I was planning on using those just to get used to the atlas.

Would it still be such a hassle to to get a 9.25 with a focal reducer or use hyperstar? I'm hesitant to buy a smaller scope because I'm still in high school (with no job) and I have to fund all this my self.

#15 orlyandico

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Posted 06 July 2013 - 11:49 PM

1) to use Hyperstar, you would want a dedicated astro CCD. You can't mount your D700 on the front of the SCT because its size would produce a large obstruction and the irregular profile would produce funny diffraction artifacts. Also the Hyperstar can't cover an FX sensor.

You do know that with Hyperstar the camera mounts in front, right?

2) Uncle Rod will say otherwise, but in my experience the f6.3 reducer can't even cover DX frame adequately, so FX is totally out.

No offense, but considering that you say you need to self-fund, I would not go with a C9 or C11. These are long focal length scopes, and will require a lot of effort to get working well. "A lot of effort" = lots of money on the mount.

#16 DuncanM

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Posted 07 July 2013 - 02:31 AM

1) to use Hyperstar, you would want a dedicated astro CCD. You can't mount your D700 on the front of the SCT because its size would produce a large obstruction and the irregular profile would produce funny diffraction artifacts. Also the Hyperstar can't cover an FX sensor.

You do know that with Hyperstar the camera mounts in front, right?

2) Uncle Rod will say otherwise, but in my experience the f6.3 reducer can't even cover DX frame adequately, so FX is totally out.

No offense, but considering that you say you need to self-fund, I would not go with a C9 or C11. These are long focal length scopes, and will require a lot of effort to get working well. "A lot of effort" = lots of money on the mount.


Celestron makes an F-7 reducer for the C-11 Edge HD OTA, that will cover a full frame camera. Starizona makes a F-7.5 reducer corrector for the C-11 that will cover full frame as well.

#17 orlyandico

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Posted 07 July 2013 - 03:27 AM

True, but (1) the reduction is 0.7 - 0.75 so the focal length reduction is not that great. Honestly even the 0.63 reduction of the regular reducer, with a C9 (2350mm) gives 1480mm which is still not an easy task for an Atlas.

Optec makes a 0.5X reducer which I've seen very good pictures from. It would reduce a C9 to 1175mm which is better. It definitely doesn't cover FX though.

I actually am thinking of getting the Starizona reducer for my non-EDGE C9, but last I checked it was back-ordered for 3-4 months.


2) The OP didn't say he was getting an EDGE (which costs significantly more than a regular C11).

#18 rmollise

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Posted 07 July 2013 - 08:07 AM


2) Uncle Rod will say otherwise, but in my experience the f6.3 reducer can't even cover DX frame adequately, so FX is totally out.


I will say otherwise. :lol:

If this is so, how the hell did we get such good results with the r/c with full-frame 35mm film for so many years?! :gramps:

HOWSOMEEVER...that doesn't mean I am endorsing a C11 as a beginning imaging scope. A C8 with a reducer/corrector is a much better choice. It will preserve your hairline and the only "downside" vice the 11 is MORE FIELD. ;)

#19 orlyandico

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Posted 07 July 2013 - 08:14 AM

Uncle Rod, I have given your statement a lot of thought. And I don't have a good theory to explain your findings. I can say though that the vignetting is very strong even on DX / APS-C sensor, in my experience.

#20 dragonslayer1

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Posted 07 July 2013 - 10:07 AM

Jmandell,
I am not as experienced as the rest of these guys probably, but I would say look into Video-photography as another avenue. Apparently you can pick up a Video-cam fairly cheap, the exposure times on it are a lot less, and probably will need a lot less accessories. I f you are starting out, I would strongly suggest you at least check it out and possibly save yourself a lot of money. Just make sure you view possible options before you commit to one road..
Kasey

#21 Ed Wiley

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Posted 07 July 2013 - 10:55 AM

The only "pretty picture" astrophotography I do is DSLR on my Kenko Skymemo. You have an Astrotrac. You can spend years with such a setup using lenses 200mm and less and there are scores of good targets on which to perfect your skills. I have never, ever, tried a 500mm on my Kenko and I am betting that my Kenko set on a Losmandy G-11 tripod is more stable than your astrotrac. I have used a 300mm which is pushing even my rig.

Save yourself frustration, enjoy wide-field imaging for now, which can include some interesting variable work with a DSLR: see the Citizen Skies initiative. Google Citizen Sky.

Ed

BTW I do photometry, but not with my C11, I use my SN8" with my ST402ME and photometric filters. Much easier on the tracking. Watch out for hyperstar: AAVSO suggests that it is not good for variable work. (No, I do not wish to debate this, just passing on information I have read.)

Also, I feel that my C11 on a Losmandy G11 is pushing the limits for what I use it for: high resolution imaging with a webcam. I don't know much about the Atlas but I would not load it more than 50% capacity if you wish to do astrophotography through the OTA.

#22 wz2

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Posted 07 July 2013 - 11:24 AM

Jmandell,

Have you thought about a good, short focal length refractor? If your budget allows maybe one of the 4 element designs specifically intended for imaging. Light weight so not so hard on the mount. And you don't necessarily need real long subs with a faster instrument. People get great shots even using 60mm instruments.

Chris

#23 rmollise

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Posted 07 July 2013 - 06:56 PM

Uncle Rod, I have given your statement a lot of thought. And I don't have a good theory to explain your findings. I can say though that the vignetting is very strong even on DX / APS-C sensor, in my experience.


I can't speak to every setup and every sky condition, but a flat field or just Gradient Xterminator will take care of this kind of problem and you really should be doing flats anyway. ;)

I used to love to shoot widefield with my ST2000 and a fracking Meade 3.3 reducer. Vignetting? Hell, it looked like you were looking through a freaking porthole. :lol:

A good flat applied, and poof, gone.

#24 jmandell

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Posted 07 July 2013 - 09:07 PM

Taking the advice from everyone, I think that I will go with an atlas and a shorter focal length scope with my dslr, then move onto a CDC and bigger scope latter.

The two that I've been looking at are the at6rc and the at65edq. I chose these two because they seem to be very good based on the reviews and they are cheap enough so that I won't have to sell my 12"


Thanks

#25 jmandell

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Posted 07 July 2013 - 09:12 PM

The only "pretty picture" astrophotography I do is DSLR on my Kenko Skymemo. You have an Astrotrac. You can spend years with such a setup using lenses 200mm and less and there are scores of good targets on which to perfect your skills. I have never, ever, tried a 500mm on my Kenko and I am betting that my Kenko set on a Losmandy G-11 tripod is more stable than your astrotrac. I have used a 300mm which is pushing even my rig.

Save yourself frustration, enjoy wide-field imaging for now, which can include some interesting variable work with a DSLR: see the Citizen Skies initiative. Google Citizen Sky.

Ed

BTW I do photometry, but not with my C11, I use my SN8" with my ST402ME and photometric filters. Much easier on the tracking. Watch out for hyperstar: AAVSO suggests that it is not good for variable work. (No, I do not wish to debate this, just passing on information I have read.)

Also, I feel that my C11 on a Losmandy G11 is pushing the limits for what I use it for: high resolution imaging with a webcam. I don't know much about the Atlas but I would not load it more than 50% capacity if you wish to do astrophotography through the OTA.


I would not recommend a 500mm on an astrotrac! Our lens is a 60's era Nikon mirror lens and it causes all kinds of problems (strange vignette, donut bokeh, etc.). If your alignment is off by a fraction of an inch, then everything is *BLEEP* :foreheadslap:






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