DOB goto vs GEM

[kheong sann chan]

Hello, I'm trying to make a decision between the Orion Dobsonian Goto series (XT??g, either 10" or 12") and an older GEM mount, the C10-NGT on CG5 (10").

I'm interested in imaging bright objects, planets and the moon. Which one would you guys suggest as the better choice?

[MarsG76]

Hello,

 

If you want to image just the planets and the moon than a tracking Dobsonian will be OK. For deep sky and long exposure you will need a equatorial mount. That said if you go for a equatorial mount, the CG5 is too small for a 10" scope. I'd recommend, as a absolute minimum, a CGEM, or preferably CGEM DX for a scope that big.

I use a 8" SCT on a CGEM mount at it works great for imaging.

 

[kheong sann chan]

Thanks for the reply. Will one mount support a greater magnification than the other? I don't know the quality of the motors on either mount, whether it produces vibration and if so how much.

This will be the first big telescope I'm getting and I'm not too sure which one is better, or what to expect in either case.

Might you be able to explain a little more why you say the CG5 is too small? Will it be more likely to topple over? or is it because there will be too much vibration?

Thanks!

[Moonshane]

I would have thought that a gem would be needed even for planets to avoid field rotation?

[kheong sann chan]

I'm a newbie to astrophotography, but from a general photography perspective, bright objects like planets should require only a short exposure, perhaps less than 1 second. In 1 second, we aren't going to get any visible  field rotation.

My question is more geared towards things like the vibration that the mount can tolerate or induces and how much noise/vibration does the motor introduce if it's a concern at high magnifications? My understanding is that it's not easy to get good high magnification photos of Saturn or Mars. I'd like to get as much information as to what is the cause and where I need to invest the time and money to get the best images. (I'm looking for causes outside of "the atmosphere" which I can't do anything about except wait for better nights)

Thanks!

[ollypenrice]

Your exposures will be way  below a second for fast frame imaging.

Olly