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Bought a CGEM DX - Imaging load questions

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#1 DaemonGPF



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Posted 19 May 2013 - 09:26 AM


I just got a great deal on a CGEM DX that I couldn't pass up, so I bought it. I am a former owner of a standard CGEM and CG-5 in the EQ lineup, and have had a few Nexstar variants as well so I'm "reasonably versed" in Celestron mounts so to speak. I've used each for deep sky imaging so I'm familiar with their nuances and weight limits.

The DX on the other hand has me pondering a few thoughts, and questioning the generally accepted "50% for imaging" rule of thumb. They beefed up a few components in the head, and added regulated power management, and gave it the heavy tripod from the CGE Pro, right? So this is where it gains its added capacity. With the regulated power making things like balance slightly less critical, do you think there's any room for play on the "50%" rule in this case?

There are two scenarios going through my head right now. And the reason I'm asking the above question is because one of the scenarios involves a good deal on a standard C11.. If I went this route I would be using it for some visual (I know the DX can handle a C11 for that), but mostly for Hyperstar imaging again. If I do my math right, a C11 + Hyperstar + Camera + KWIQ guider package is going to be pushing around 34 lbs give or take a few ounces for hardware. That is about 9 lbs over the "recommended".

Do it? No? Get a C9.25 instead and do the same thing?

I had a C8 before and slapped a Hyperstar on it, and had great results, but I was always unhappy about the obstruction percentage caused by my CCD, and I couldn't use a DSLR with the C8 either. A 9.25 or 11 would take care of that issue, but is a C11 just asking for trouble or should I get it?

#2 neilson


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Posted 19 May 2013 - 11:29 AM

I had a CGEM DX and used it for imaging. I have a 9.25 Edge HD, 2" flip mirror, a guidescope and cameras and it weighed 35lbs. The mount barely knew it was there. I have read of others using an 11" with no problem for imaging. If you are worried then Hypertune it and that will make it perform even better.
I wanted an 11" but I was glad I stayed with the 9.25 because its a tall mount to lift that OTA loaded, on to the saddle every night. But I don't think the mount will have any problem with an 11". Celestron even sells the CGEM DX with a 14" OTA but I would only use it for visual with that much weight.


#3 hytham


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Posted 19 May 2013 - 12:50 PM

I had my DX loaded with an EdgeHD 11, HS3, DSLR, 9x50 Celestron with SSAG. For test purposes I was able to achieve 5 minute unguided subs and 10 minutes with guiding.

I wish I had kept the sub frames to show you, but it is in fact possible assuming you received one of the good DX units.

I have been debating hypertuning mine as well. Maybe a project for next winter.

#4 Momerath


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Posted 20 May 2013 - 06:38 AM

I can tell you I use a Edge HD 11" on a DX mount and with a DSLR, Focal reducer ( weighs a lot.) 50mm guide scope with SSAG, I can achieve 5 min unguided subs and have gone up to 15 min guided subs.

Now I am new to imaging and with this set up I have been able to Image at F10 with very little problems. Image at F7 with no problems. Since I am really new to all this, I have a hard time polar aligning, balancing and all that, but just think what a experienced person might achieve.

I think a C14 would be too much for the DX mount but a C11 is just fine.

#5 Stew57



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Posted 20 May 2013 - 08:11 AM

My experience with a C11 qnd CGEM would say 5 min unguided is a rare mount. I would not expect that performance out of either the cgem or dx. They both track the same. Guiding can be problematic depending on the particular sample you get. There are work arounds for the quirks. Just don't expect long exposures at long FL especially unguided.

#6 EFT


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Posted 20 May 2013 - 09:39 AM

Congrats on the new mount. The C11, particularly with HyperStar, should be fine on the DX. Remember that the "rule" is really just a guideline for the easiest imaging load to deal with. A well performing mount can handle more than a poorly performing mount of the same kind.

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