Return to the Cloudy Nights Telescope Reviews home page

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User

Astrophotography and Sketching >> Beginning Imaging

Pages: 1 | 2 | 3 | (show all)
MartyT
professor emeritus
*****

Reged: 09/28/07
Posts: 549
Loc: Kansas City
Re: Celestron CGE 1100 as an imaging platform? new [Re: Wmacky]
      #2624687 - 09/04/08 11:32 PM

Quote:

I'll chime in as I have this setup, but with a Eon 80mm instead of the 90. I can't comment on imaging with it due to several months of not one good clear night to get started. I will tell you why I went this route:

1 This rig will make a near unbeatable plantary imaging rig. This is something I want to also explore. No one will disagree with this.

2 The C11 has lots of Ampeture for DSO visual work!

3 The 80mm can be used to learn imaging , while Providing great Widefield shots. The C11 will be available later for High resolutiom imaging of smaller DSO's once some skills have been obtained.

4 Buying the CGE, and C11 together now results in a huge cash savings compared to buying separate componets.




Thanks for your comments -- your last point is one I keep coming back to.

The CGE mount by itself is $3000 everywhere I've checked. The C11-CF carbon fiber OTA is $2400 at Adorama but is otherwise difficult to find. That's $5400 to buy them separately.

But the CGE-1100 package consisting of both of those items is as low as $4150 (Woodland Hills). The package price differential is considerable, and in fact, quite a bit more significant than the differential for the CGE925 or CGE800 packages.

If I get the CGE 1100 package and find that the 11" OTA just won't work for my needs, I ought to be able to sell it and recover considerably more than the $1150 difference between the package price and the CGE stand-alone price, and I'll still have the CGE to play with.

Looks like I'm going to have to ruminate on this one for a few more days till I can decide the "right" way to go...

--------------------
Celestron CGE / C-11 (CGE-1100)
Megrez 90 FD APO / 0.8x FR/FF vIII
QHY8, DSI Pro (guider), SPC900NC
ETX-125AT
12" Lightbridge

My Astrophoto Gallery

Astronomical Society of Kansas City


Post Extras: Print Post   Remind Me!   Notify Moderator  
HaleBopper
sage


Reged: 01/14/08
Posts: 261
Loc: Great White North
Re: Celestron CGE 1100 as an imaging platform? [Re: Jared]
      #2624881 - 09/05/08 01:51 AM






You can't use an f/3.3 focal reducer since it is really only compatible with smaller chip cameras. That means you will be imaging at a focal length of 1,700mm at f/6.3. The typical 6.5 micron pixels of a DSLR at that focal length will give 0.75 arc seconds per pixel. At that kind of resolution, tracking needs to be virtually flawless in order to prevent star trails. The CGE is a good mount, but that is a lot to ask of it when carrying 45 pounds worth of equipment (28 pounds worth of scope, another three pounds worth of dovetails, two pounds worth of cameras, and perhaps 11 pounds of of axis guider and rings). The rated capacity of the mount is 65 pounds for visual use. Rule of thumb would suggest its capacity for photographic use is roughly half that--say thirty five pounds. A C11 with a guide scope will definitely weight more than is ideal for this mount, and the focal length of the scope will make any tracking errors obvious.




I'm not exactly a newbie myself, but I'm still very much a novice. I have the f/6.3 FR in mind. Currently I image with my C8 on a CG5 mount and have obtained ok results at 2032 mm focal length. I don't autoguide, my longest exposures have only been 2.5 min. Wouldn't the 1700 mm with the f/6.3 on the C11 be a bit easier than imaging at 2032 mm?

Thanks.

--------------------
8" SCT CG5 mount
Canon Digital Rebel 400
Kodak Easyshare 2.0 Megapixels
5, 8, 13, 17, 21, 24mm Orion Stratus


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jared
Carpal Tunnel
*****

Reged: 10/11/05
Posts: 1875
Loc: Piedmont, California, U.S.
Re: Celestron CGE 1100 as an imaging platform? new [Re: Wmacky]
      #2625255 - 09/05/08 10:11 AM

Quote:

I'll chime in as I have this setup, but with a Eon 80mm instead of the 90. I can't comment on imaging with it due to several months of not one good clear night to get started. I will tell you why I went this route:

1 This rig will make a near unbeatable plantary imaging rig. This is something I want to also explore. No one will disagree with this.

2 The C11 has lots of Ampeture for DSO visual work!

3 The 80mm can be used to learn imaging , while Providing great Widefield shots. The C11 will be available later for High resolutiom imaging of smaller DSO's once some skills have been obtained.

4 Buying the CGE, and C11 together now results in a huge cash savings compared to buying separate componets.




1) No argument here. It's a great choice for planetary imaging where exposures are as short as possible. Plenty of focal length for reasonable image scale, and plenty of aperture for resolution.

2) Definitely a great choice for visual work. Again, no argument.

3) Yes on the 80, and you are right that the C11 itself is good for smaller targets due to its aperture and focal length.

4) Yes, the price is certainly attractive for the bundle.

Hey, who am I to say what is and isn't possible with a mount I don't own? I just want to make sure Marty knows what he's biting off before he spends this kind of money. My primary imaging scope is an 8" modified Dall Kirkham with 1800mm focal length. It only weights sixteen pounds, and I don't use an off axis guide scope since my camera is self-guided. Total weight I put on my mount is roughly twenty-three pounds plus counter weights. The rated capacity of the mount is forty-six pounds for photographic use, and it's mounted on a very sturdy portable pier. It's an expensive mount--significantly more expensive than the CGE--and so my expectations for it are quite high. It's up to the task, and I have been very pleased with the combination. That being said, I took it out last Saturday on a very breezy evening and had to give up in frustration. Between the poor seeing and the wind there was just no way to capture an image of more than thirty seconds without star trails. Imaging with an even larger scope at even longer focal lengths is hard.

Marty, it sounds like you really want the CGE-11, and it's certainly a fine piece of kit and a good value. Please take my advice in the spirit in which it was intended--helpful. If you think you will overcome the obstacles, more power to you! Go for it!

--------------------
- Jared Willson
  • Fluorostar FLT-110 w/ TEC optics
  • Vixen VC200L
  • Astro-Physics Mach1 GTO
  • Stellarvue SV80S
  • Takahashi Teegul SP Mount
  • STL-11000



Post Extras: Print Post   Remind Me!   Notify Moderator  
Jared
Carpal Tunnel
*****

Reged: 10/11/05
Posts: 1875
Loc: Piedmont, California, U.S.
Re: Celestron CGE 1100 as an imaging platform? new [Re: HaleBopper]
      #2625291 - 09/05/08 10:31 AM

Quote:






You can't use an f/3.3 focal reducer since it is really only compatible with smaller chip cameras. That means you will be imaging at a focal length of 1,700mm at f/6.3. The typical 6.5 micron pixels of a DSLR at that focal length will give 0.75 arc seconds per pixel. At that kind of resolution, tracking needs to be virtually flawless in order to prevent star trails. The CGE is a good mount, but that is a lot to ask of it when carrying 45 pounds worth of equipment (28 pounds worth of scope, another three pounds worth of dovetails, two pounds worth of cameras, and perhaps 11 pounds of of axis guider and rings). The rated capacity of the mount is 65 pounds for visual use. Rule of thumb would suggest its capacity for photographic use is roughly half that--say thirty five pounds. A C11 with a guide scope will definitely weight more than is ideal for this mount, and the focal length of the scope will make any tracking errors obvious.




I'm not exactly a newbie myself, but I'm still very much a novice. I have the f/6.3 FR in mind. Currently I image with my C8 on a CG5 mount and have obtained ok results at 2032 mm focal length. I don't autoguide, my longest exposures have only been 2.5 min. Wouldn't the 1700 mm with the f/6.3 on the C11 be a bit easier than imaging at 2032 mm?

Thanks.




2.5 minutes unguided at 2,000mm is almost unbelievably good. Typical periodic error for the CG-5 is 20 arc seconds or more, and 2.5 minutes is long enough to cover a significant part of the worm period. Even with absolutely perfect polar alignment I am surprised you can get that long an exposure. Nice work. As to whether the C11 would be easier at f/6.3... The 1,700mm focal length would be a bit easier, but the extra weight and aperture would pose a larger challenge for the mount. I'd expect these two factors to roughly cancel. Probably about the same challenge, though the extra aperture of the C11 would get you better signal to noise ratio for a given exposure duration so it would probably produce better pictures for most subjects.

Congrats on getting that kind of exposure unguided on a CG5! That's outstanding. I could never get more than one minute exposures on my CG5 unguided at 715mm focal length due to periodic error. Your experience is not common.

--------------------
- Jared Willson
  • Fluorostar FLT-110 w/ TEC optics
  • Vixen VC200L
  • Astro-Physics Mach1 GTO
  • Stellarvue SV80S
  • Takahashi Teegul SP Mount
  • STL-11000



Post Extras: Print Post   Remind Me!   Notify Moderator  
Qkslvr
Pooh-Bah


Reged: 06/23/06
Posts: 1054
Loc: NE Ohio, US
Re: Celestron CGE 1100 as an imaging platform? new [Re: Jared]
      #2625307 - 09/05/08 10:41 AM

I get a reasonable number of sub's @ 30s on a CG-5 @1280mm with a C8 (2000mm + f/6.3)

--------------------
Mike
N8/CG-5/40D
Coming sometime/Maybe FrankenRebel


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jared
Carpal Tunnel
*****

Reged: 10/11/05
Posts: 1875
Loc: Piedmont, California, U.S.
Re: Celestron CGE 1100 as an imaging platform? new [Re: Qkslvr]
      #2625311 - 09/05/08 10:43 AM

Quote:

I get a reasonable number of sub's @ 30s on a CG-5 @1280mm with a C8 (2000mm + f/6.3)




That's much more typical. Exactly what I would expect one to be able to achieve with that OTA and that mount. Nice job.

--------------------
- Jared Willson
  • Fluorostar FLT-110 w/ TEC optics
  • Vixen VC200L
  • Astro-Physics Mach1 GTO
  • Stellarvue SV80S
  • Takahashi Teegul SP Mount
  • STL-11000



Post Extras: Print Post   Remind Me!   Notify Moderator  
HaleBopper
sage


Reged: 01/14/08
Posts: 261
Loc: Great White North
Re: Celestron CGE 1100 as an imaging platform? new [Re: Jared]
      #2625393 - 09/05/08 11:36 AM






Congrats on getting that kind of exposure unguided on a CG5! That's outstanding. I could never get more than one minute exposures on my CG5 unguided at 715mm focal length due to periodic error. Your experience is not common.




Thank you, but my shots are not all that great. I have only managed 2.5 min on one occasion and I had to throw out at least half of my subs. I do a bit better with 2 min subs but I still throw out many subs. Sometimes I get reasonably round stars on one sub, and on the next I get either tailing or a ghostly faint second star by the original. I use anti-vibe pads, but the slightest breeze or passing truck can ruin a shot. I have tried east heavy mounting as well. I assume that if I face polaris, the east side of the mount would be my on right side?

Here is a posted image of NGC 891. These were 2 min subs from my yard. All my shooting is from my yard and so LP is a problem. I have to process quite a bit and my skills are shall we say, "lacking." Someone with better skills and processing experience can do much better with my set-up than I can.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2613759/page/2/view/collapsed/sb/5/o/all/fpart/1

Here is a pic of M15 with 2 min subs. You can see some tailing. Some subs had round stars, others elongated. A pic I took of M92 was a great deal better, but I was using 1 min subs.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2608258/page/4/view/collapsed/sb/5/o/all/fpart/1

How does this tie in with a C11 on CGE? I would like more aperture for one, and I want to be able to image. My current set-up is overloaded. I think the CG5 is rated for 30 lbs. So, my C8 is 13lbs, plus maybe 2 lbs for the dslr etc, and the two counterweights at about 22 pounds, put me about 7 pounds over. I thought I could do better with a C11 on a CGE, for visual and AP.

By the way, I like my CG5. For visual, I could not ask for more. Great Gotos, easy to set up.

Thank you again for your input.

--------------------
8" SCT CG5 mount
Canon Digital Rebel 400
Kodak Easyshare 2.0 Megapixels
5, 8, 13, 17, 21, 24mm Orion Stratus


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jared
Carpal Tunnel
*****

Reged: 10/11/05
Posts: 1875
Loc: Piedmont, California, U.S.
Re: Celestron CGE 1100 as an imaging platform? new [Re: HaleBopper]
      #2625671 - 09/05/08 02:19 PM

Quote:


Thank you, but my shots are not all that great. I have only managed 2.5 min on one occasion and I had to throw out at least half of my subs. I do a bit better with 2 min subs but I still throw out many subs. Sometimes I get reasonably round stars on one sub, and on the next I get either tailing or a ghostly faint second star by the original. I use anti-vibe pads, but the slightest breeze or passing truck can ruin a shot. I have tried east heavy mounting as well. I assume that if I face polaris, the east side of the mount would be my on right side?




That's actually pretty much what I would expect. The double stars come from a sudden "shift" (usually in right ascension, but with a breeze it could also be in declination). This can be caused by:
  • A slightly west-heavy balance since "holding the scope back" is never as smooth as "pushing it forward". Tracking can get quite jerky if you aren't perfectly balanced or even slightly east-heavy
  • A breeze taking up backlash in either axis
  • binding between the worm and wheel--you want to make sure there is NO binding of any kind here--it should be smooth as silk even at the risk of increasing backlash somewhat
  • Binding in the RA axis bearings under a heavy load--not much you can do about this
  • Lack of smoothness in RA tracking because of surface roughness on the worm; best way to diagnose this is to see if you get the same jumps/trailing at the same time point in your worm cycle
You have the east/west heavy thing correct. If you are facing north and your scope is pointed at the object you wish to image, you want to make sure the right side of the mount is slightly heavier than the left. You're looking for just a few ounces difference at most here or you will make the motors strain. If the counterweight shaft is pointed vertically (when the telescope is virtually on top of the mount), then you may need to make your adjustment by shifting the OTA rather than the counterweights. The counterweights don't have any leverage in this position.

Quote:

Here is a posted image of NGC 891. These were 2 min subs from my yard. All my shooting is from my yard and so LP is a problem. I have to process quite a bit and my skills are shall we say, "lacking." Someone with better skills and processing experience can do much better with my set-up than I can.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2613759/page/2/view/collapsed/sb/5/o/all/fpart/1




That's actually quite good. Looks like you have a bit of RA error (either periodic or random) as well as some field curvature (which is to be expected when using an SCT with a large chip, even if you have a focal reducer/field flattener), but for two minutes unguided I'd be pretty pleased with those data. Obviously, the more you practice your post processing skills the better the results will be. Nice work.

Quote:

Here is a pic of M15 with 2 min subs. You can see some tailing. Some subs had round stars, others elongated. A pic I took of M92 was a great deal better, but I was using 1 min subs.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2608258/page/4/view/collapsed/sb/5/o/all/fpart/1




Some minor star trails, but again that is a very nice result. Good work. The fact that your picture using 1 minute subs was better should be a clue, though... If you are getting better results at that subexposure duration, use it. You may need more total exposure time to get a given signal to noise ratio since your read noise levels will be higher, but you will also be throwing out fewer "bad" exposures. From what you have shown, I'd probably stick with one minute unguided subexposures. If you want to do longer, try adding an autoguider.

Quote:

How does this tie in with a C11 on CGE? I would like more aperture for one, and I want to be able to image. My current set-up is overloaded. I think the CG5 is rated for 30 lbs. So, my C8 is 13lbs, plus maybe 2 lbs for the dslr etc, and the two counterweights at about 22 pounds, put me about 7 pounds over. I thought I could do better with a C11 on a CGE, for visual and AP.




I expect you could do better with the C11 and the CGE. I can't say from personal experience, though... The PE curves I have seen for CGE's usually show much smoother tracking than a CG-5. The unintended double stars would probably go away, for example. That being said, the CGE still has significant total periodic error, even if it is a great deal smoother than the CG-5. Even fairly small PE amounts will be quite visible at the type of focal lengths you are talking about using, and the CGE seems to average somewhere around +/- 8 arc seconds, though the sample variation is significant. Plan on needing an autoguider if you want to take longer exposures.

Quote:

By the way, I like my CG5. For visual, I could not ask for more. Great Gotos, easy to set up.

Thank you again for your input.




Yup, the CG-5 is a heck of a nice mount for visual use with an 8" or smaller scope. Simple, light, reliable, easy to setup, and inexpensive.

Good Luck!

--------------------
- Jared Willson
  • Fluorostar FLT-110 w/ TEC optics
  • Vixen VC200L
  • Astro-Physics Mach1 GTO
  • Stellarvue SV80S
  • Takahashi Teegul SP Mount
  • STL-11000



Post Extras: Print Post   Remind Me!   Notify Moderator  
MartyT
professor emeritus
*****

Reged: 09/28/07
Posts: 549
Loc: Kansas City
Re: Celestron CGE 1100 as an imaging platform? new [Re: Jared]
      #2626158 - 09/05/08 07:05 PM

Thanks again for all the comments, Jared - I've certainly got a lot to think about before I dive into this. Still leaning heavily toward the CGE 1100, but haven't really made up my mind for sure.

--------------------
Celestron CGE / C-11 (CGE-1100)
Megrez 90 FD APO / 0.8x FR/FF vIII
QHY8, DSI Pro (guider), SPC900NC
ETX-125AT
12" Lightbridge

My Astrophoto Gallery

Astronomical Society of Kansas City


Post Extras: Print Post   Remind Me!   Notify Moderator  
EWhytsell
super member


Reged: 06/15/08
Posts: 165
Loc: North Central Ohio
Re: Celestron CGE 1100 as an imaging platform? new [Re: MartyT]
      #2626345 - 09/05/08 09:20 PM

My opinion is get the scope you want to get and don't look to far into everyones opinions/experiences to much unless they have something like (don't buy this because it will fail) to say.

Sounds like you want the bigger scope and its been my experience that anytime I got the smaller, car, scope, whatever I always end up getting the better one in the end because its what I wanted and continued to want after getting something else. sorry for added confusion:-)

Evan

--------------------
Classic C8 Super Polaris upgraded to CG-5 mount
Canon 40D unmodded


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jared
Carpal Tunnel
*****

Reged: 10/11/05
Posts: 1875
Loc: Piedmont, California, U.S.
Re: Celestron CGE 1100 as an imaging platform? new [Re: MartyT]
      #2626370 - 09/05/08 09:36 PM

Quote:

Thanks again for all the comments, Jared - I've certainly got a lot to think about before I dive into this. Still leaning heavily toward the CGE 1100, but haven't really made up my mind for sure.




No problem, Marty. I just want to make sure you getting into it 'eyes open,' as they say. I certainly wouldn't want to discourage you from buying what you really want.

--------------------
- Jared Willson
  • Fluorostar FLT-110 w/ TEC optics
  • Vixen VC200L
  • Astro-Physics Mach1 GTO
  • Stellarvue SV80S
  • Takahashi Teegul SP Mount
  • STL-11000



Post Extras: Print Post   Remind Me!   Notify Moderator  
HaleBopper
sage


Reged: 01/14/08
Posts: 261
Loc: Great White North
Re: Celestron CGE 1100 as an imaging platform? new [Re: Jared]
      #2626923 - 09/06/08 07:48 AM

I'm mulling it over myself. So I'm probably near the max for AP?

The OTA is 28 lbs, add about 2 or so for the finder plus dslr etc, and we're at 30 lbs. Counterweights need to be included right? If so, then the 25 lb counterweight brings me to 55 lbs. The CGE capacity is 65 lbs. THis is before any autoguiding equiment is added. Either way, I'm at the limit am I right?

How easy is it to connect CG5 C8 to fit on a CGE?

Thanks.

--------------------
8" SCT CG5 mount
Canon Digital Rebel 400
Kodak Easyshare 2.0 Megapixels
5, 8, 13, 17, 21, 24mm Orion Stratus


Post Extras: Print Post   Remind Me!   Notify Moderator  
freestar8n
member


Reged: 10/12/07
Posts: 72
Re: Celestron CGE 1100 as an imaging platform? new [Re: MartyT]
      #2627072 - 09/06/08 10:11 AM

Hi-

I have the cge1100 and I image at f/10 using off-axis guiding. I find that it can be guided well and you will get tight round stars as long as you do it right. The total cost for an imaging solution based on the cge1100 is very low, and OAG helps reduce both cost and weight, but you do have to find guide stars.

Example images are at:

http://www.astrogeeks.com/Bliss/MetaGuide/images/index.html

I strive for round stars with fwhm in the low 2".

The 11" is great for visual, planetary, and deep sky imaging. If you want to do planetary, you can invest in a lumenera camera and use it to guide, as I do. This will give it double duty as guider and planetary imager. Here is a rough breakdown of costs in my setup:

cge1100 $4000
lumenera skynyx 2-0 $995
Taurus mini-tracker off-axis guider $200
Guide software free
pectool for pec averaging - free from celestron
gpusb for guiding, or serial cable if using ascom

To this you would add things like robo-focus, dew heaters, and color filters/wheel if you do planetary imaging.

But this has minimal added weight due to the OAG, and there is no need for losmandy stuff and its weight.

The main concern I have about the c11 and guidescope guiding is flexure due to internal components of the SCT. Tightening the guidescope won't help with this, and the only solution is shorter exposures. You can either stick to shorter focal length, or shorter exposures. If you go to OAG, you will have to find guidestars, but many other problems will go away, and you can achieve very good results with this setup and some effort. Plus - you'll have the same OTA Chris Go uses for his Jupiter images.

Good luck with your decision. If you want easier guiding, you could get a cge with a good refractor as main OTA, and guide it with a guidescope. But a good refractor plus a mount will be more than $4000.

Frank


Post Extras: Print Post   Remind Me!   Notify Moderator  
HaleBopper
sage


Reged: 01/14/08
Posts: 261
Loc: Great White North
Re: Celestron CGE 1100 as an imaging platform? new [Re: freestar8n]
      #2627165 - 09/06/08 11:07 AM

Sounds interesting. I may try OAG on my CG5 just to gain more experience. What do you think of Celestron's off axis guider? I find the 12.5 mm illuminated Celestron ep is quite expensive. What ep focal length or brand do you recommend?

Thank you.

--------------------
8" SCT CG5 mount
Canon Digital Rebel 400
Kodak Easyshare 2.0 Megapixels
5, 8, 13, 17, 21, 24mm Orion Stratus


Post Extras: Print Post   Remind Me!   Notify Moderator  
freestar8n
member


Reged: 10/12/07
Posts: 72
Re: Celestron CGE 1100 as an imaging platform? new [Re: HaleBopper]
      #2627271 - 09/06/08 12:04 PM

Quote:

Sounds interesting. I may try OAG on my CG5 just to gain more experience. What do you think of Celestron's off axis guider? I find the 12.5 mm illuminated Celestron ep is quite expensive. What ep focal length or brand do you recommend?





Hi-

I meant to use OAG with the lumenera as guider. This means no eyepiece. You can also guide with it visually, but that is certainly less common nowadays.

Your c5 may have much less internal flexure than the c11, so guidescope guiding may be fine for it, especially if you do it visually. I imagine the OAG would be less ideal for the c5 also, because it is smaller.

For OAG you want some controls over the mirror - by rotating it and tilting or sliding it. I think the simple celestron one doesn't provide this, and the pickoff mirror may be small.

The main reason to go to OAG is to avoid flexure, but it also reduces weight and the cost of a guidescope and mounting hardware.

Frank


Post Extras: Print Post   Remind Me!   Notify Moderator  
HaleBopper
sage


Reged: 01/14/08
Posts: 261
Loc: Great White North
Re: Celestron CGE 1100 as an imaging platform? new [Re: freestar8n]
      #2627282 - 09/06/08 12:12 PM

I have a C8 on a CG5. THe reason I thought of OAG was because my mount is already overweight and I did not want to add too much more.

Is there a link to the "luminera" you are using? I'm curious about it.

Thanks for your help.

--------------------
8" SCT CG5 mount
Canon Digital Rebel 400
Kodak Easyshare 2.0 Megapixels
5, 8, 13, 17, 21, 24mm Orion Stratus


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jared
Carpal Tunnel
*****

Reged: 10/11/05
Posts: 1875
Loc: Piedmont, California, U.S.
Re: Celestron CGE 1100 as an imaging platform? new [Re: HaleBopper]
      #2627401 - 09/06/08 01:23 PM

Quote:

The OTA is 28 lbs, add about 2 or so for the finder plus dslr etc, and we're at 30 lbs. Counterweights need to be included right? If so, then the 25 lb counterweight brings me to 55 lbs.




Counterweights are NOT included in the mount capacity for most manufacturers. Only instrument weight. You are well under the rated capacity for the CGE. The catch is that the rated capacity is for visual use. Long exposure astrophotography requires the smoothest tracking you can afford so that the autoguider can do its job. The rule of thumb is that the photographic capacity of any mount is roughly 50% of the visual capacity of the mount. This can't be a precise number, of course, since the diameter of the OTA, length of the OTA, and focal length of the OTA all play a role as well. The 50% guideline for photographic use is quite conservative. There are people who have gotten good tracking at significantly higher loads. It varies from person to person (skill level), mount to mount (sample variation), and viewer to viewer (how "good" is "good enough?"). Frank has posted some excellent examples of what is possible when this scope is well guided on a CGE.

--------------------
- Jared Willson
  • Fluorostar FLT-110 w/ TEC optics
  • Vixen VC200L
  • Astro-Physics Mach1 GTO
  • Stellarvue SV80S
  • Takahashi Teegul SP Mount
  • STL-11000



Edited by Jared (09/06/08 01:37 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
mclewis1
Thread Killer
*****

Reged: 02/25/06
Posts: 2454
Loc: Colorado
Re: Celestron CGE 1100 as an imaging platform? new [Re: HaleBopper]
      #2627419 - 09/06/08 01:31 PM

About a year ago I deforked an NS11 so that I could mount the OTA on a CGE and explore imaging with the C11. Previously I had imaged with a C6 and an 80mm ED scope on a CG5.

I love the CGE, very robust and very good tracking but if you are going to work with fl of 1700-2850 you had better be prepared to spend a substantial amount of time wringing out every possible tracking/guiding issue you could ever imagine. You'll also become an expert in mechanical flexure and will get to know every nut, bolt, and connection on your mount and scope.

Most nights on most objects I am much more likely to image with either the C6 or TMB115 on the CGE than the C11 (the smaller scopes are just more forgiving when imaging). My CGE/C11 is transported to the backyard on a Scopebuggy and the tripod legs are placed on small concrete pads so my setup is quite consistent. Even so I really think that to be able to consistently image with a C11 a more permanent setup would be preferred. I find that there are simply too many variables that crop up when imaging at 2800mm when you setup and break down for each session. A larger class of mount (Titan or NJP for example) would likely be more effective in that type of situation.

For visual or video imaging work the combination of a C11 and a smaller scope on a CGE is just about perfect (less need for extremely accurate tracking). I also really prefer a side by side or tandem scope mounting to going with a piggyback setup. I get much more flexibility with the side by side ... there is no way I could have all the following combinations with a piggyback setup (C11/80mm, C11/C6, C11/TMB115, C6/80mm, TMB115/C6, TMB115/80mm).

I'd go ahead buy the CGE1100 with a side by side mounting setup. Then I'd also get a used C8 or C6 and use one of them for imaging before putting the time into the C11.

--------------------
Mark

C11, C6, APM/TMB115, and AT80ED
Tandem mount CGE and CG-5A, WO EZ-Touch and AT Voyager
25x100s, 8x56s, T-Mount Light, and Mark 1 eyeballs
Modded 350D, SPC900, Mallincam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jared
Carpal Tunnel
*****

Reged: 10/11/05
Posts: 1875
Loc: Piedmont, California, U.S.
Re: Celestron CGE 1100 as an imaging platform? [Re: mclewis1]
      #2627436 - 09/06/08 01:42 PM

Thanks for chiming in, Mark! This is exactly what I would have expected based on the results I have seen from this setup and from interactions with other astrophotographers trying to image at these focal lengths. Your comments carry much more weight than mine, though, since you actually own the equipment in question.

--------------------
- Jared Willson
  • Fluorostar FLT-110 w/ TEC optics
  • Vixen VC200L
  • Astro-Physics Mach1 GTO
  • Stellarvue SV80S
  • Takahashi Teegul SP Mount
  • STL-11000



Post Extras: Print Post   Remind Me!   Notify Moderator  
HaleBopper
sage


Reged: 01/14/08
Posts: 261
Loc: Great White North
Re: Celestron CGE 1100 as an imaging platform? [Re: Jared]
      #2627494 - 09/06/08 02:15 PM

Thanks guys for clearing up some issues for me.

--------------------
8" SCT CG5 mount
Canon Digital Rebel 400
Kodak Easyshare 2.0 Megapixels
5, 8, 13, 17, 21, 24mm Orion Stratus


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | (show all)


Extra information
10 registered and 2 anonymous users are browsing this forum.

Moderator:  Charlie Hein, knuklhdastnmr 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 736

Jump to

Home



Cloudy Nights Sponsor: Astronomics