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Celestron CGEM vs CG-5 mounts

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#1 berobertsmd

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Posted 01 April 2011 - 09:15 AM

I'm trying to get suggestions concerning these 2 mounts used with a Celestron 925 SCT OTA. I would think the CGEM would be superior. One of my main concerns is breakdown weight. I'm trying to limit each of scope's single component weight to 30# or less. The total assembled weight is not that important, just can't carry more than 30# at 1 time. Would like to try to get into basic DSLR astrophoto at some point. Celestron has these mounts, with a 925 OTA on sale this month. I currently have a CPC 925 XLT, which has been a great scope, but is too heavy.(top 1/2 is 58#). I live in a small state, so no local astro dealer or astronomers where I can compare these mounts eye to eye. Any suggestions appreciated. Thanks-
Bruce

#2 RTLR 12

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Posted 01 April 2011 - 09:32 AM

If you truly want to limit the weight to 30# the CGEM just won't do. The CGEM mount head weighs 41# alone.
The CG-5 is very capable of handling the 9.25 and weight wise is much, much lighter. I'm not sure of the weight, but I carry mine in one hand. As for AP work, it is possible with the CG-5 although some what more work and possibly limiting at times. The CGEM is a much steadier platform and a bit more precise than the CG-5, but people are getting very good results from the CG-5. When just starting out in AP it should serve you well.

Stan

#3 Mike X.

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Posted 01 April 2011 - 09:54 AM

Hello,
the CG5-GT is a good mount for starting astrophotography and it can give great results but in long exposure the C9 is a litle bit too much for it,if astrphotography is the purpose of the setup.
The CGEM is with no doubt far better than the CG5-GT and more capable o carying the C9 without pushing the mount to it's limits.

From my personal experience an ASGT (alias CG5-GT) mount can handle with no problems for long exposure a total weight up to 10kgs ( i think thats a about 25pounds give or take).I'm using my setup at this weight ASGT+C6+Equinox 80 ED +Canon EOS 500D+rings etc and it works just great.

More than that and i think you will have excessive vibrations or balancing will be more critical or even the telescope will be more affected from the wind.

It all depends from the use you wish to do.
The CG5 wont' break under the weight of a C9 but i'm afraid you won't be able to do more than Planetary immaging with a light webcam such as an SPC900N or a Neximage,at least not as you would like to.

I hope this info helps ;)

#4 hfjacinto

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Posted 01 April 2011 - 10:22 AM

I have the 9.25 and a CGEM. I had a CG5 and I image.

The CGEM is very heavy and weighs more than the 30 lbs you are looking at. The GC5 is capable of having the 9.25 for visual, but I would not recommend it for imaging. The CGEM with a guide scope on the 9.25 is over the recommended weight limit. The below was taken with the 9.25, rings and an 80MM APO as a guide scopen so its doable, but any wind stops the AP process.

My recommendations if purely visual the CG5 is adequate. If imaging the CGEM is capable but its a beast.

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#5 PHampson

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Posted 01 April 2011 - 11:23 AM

You might look into the new IOptron IEQ45 mount. It handles up to 45 lbs. but only weighs 25 lbs. itself. The software is different from the Celestron Nexstar that you are used to but, really, from my experience, it is very similar and just as easy to use. I haven't had mine very long but I have been able to do some imaging at 1.02 arcsec/pixel and it works very well. I don't yet have a C9.25 but my plan is to get one soon for use on this mount. There is an extensive thread on the forum discussing the mount. All of the balance issues discussed there no longer apply as IOptron has released firmware with electronic balancing - the mount checks the balance with the motors and tells you which way and how much to shift the counterweights for RA and OTA for DEC. It works great and is quite impressive. Good luck.


Paul

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#6 berobertsmd

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Posted 01 April 2011 - 03:44 PM

Thanks for the input so far! As far as weight, It sounds like the CGEM is too heavy. I wondering if it would be "better" to drop back to a C8 on the CG-5, due to weight of OTA and also wind if trying to use for basic AP, although I hate to lose the extra 1.25" diameter.
Bruce

#7 hfjacinto

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Posted 01 April 2011 - 03:47 PM

Bruce,

For imaging a fast small scope is really all you need. For Visual aperture rules. The club members that start imaging with a C8 and GC5 all sold the GC5 or the C8. The focal length was too long to get images with the C8/GC5 combo (not that it can't be done, but its not easy and not recommended for a beginner). The GC5 is a good mount, but you really need to consider the weight that you put on it for imaging.

#8 skybsd

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Posted 01 April 2011 - 03:57 PM

Hi Bruce,

Thanks for the input so far! As far as weight, It sounds like the CGEM is too heavy. I wondering if it would be "better" to drop back to a C8 on the CG-5, due to weight of OTA and also wind if trying to use for basic AP, although I hate to lose the extra 1.25" diameter.
Bruce


Are you hoping to replace your current CPC-9.25 or something?

Regards,

skybsd

#9 berobertsmd

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Posted 01 April 2011 - 05:48 PM

It's looking like I may need to replace my CPC 925 with something lighter in weight for health reasons. Without the boring details, I've found out about some back problems that require me to try to limit my heavy lifting. The CPC has been great, but is heavy, and if I want to get into AP, I'd need a wedge, which is even more weight to the 58# upper unit. With all that in mind, I'm trying to see what my best options are. Right now, I'm mainly interested in visual observation, but would like to get into basic AP at some point. Am fairly new to astronomy, so most of my accessories are geared towards Celestron SCT and would want a GT mount.
Bruce






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