I want a GEM mount!!!

shirox · Post by **shirox** » Wed Feb 16, 2011 4:37 pm

Ok, i'm a complete noob to mounts and stuffs... To prevent impusive buying and regretting my decision later, i am looking for a GOTO GEM with payloads to about 20kg.

Vixen SXD
Orion Atlas EQ-G
Celestron CGEM
Losmandy G11

Read some pro and cons of the various mounts like Goto not as comprehensive bla.

Your valuable input is greatly appreciated lol

chip · Post by **chip** » Wed Feb 16, 2011 4:47 pm

WOW! is this your first GEM purchase? this is a very huge leap forward, IMHO.

For me personally, I would chose a mount to fit a certain purpose. These mounts listed above are quite "heavy" duty, and suits astrophotography well. But I think you can settle for something lighter if visual observation is your target.

Considering my small body size, I would have a hard time making it a portable setup. However, if this is to be a permanent, I'll leave it to the other Pros here to discuss because I personally have no experience with these kinds of serious gears.

andeelym · Post by **andeelym** » Wed Feb 16, 2011 4:51 pm

I am actually going for a minitower turbo (by trapezium) and a EQ wedge. At least its portable and easy to setup. And it can carry what I want it to carry.

In the future when i can have a more perm setup, then i'll go for a heavy GEM.

shirox · Post by **shirox** » Wed Feb 16, 2011 5:05 pm

This is going to be a permanent set up for AP at home and maybe to astro trips up north.
For usual ob sessions i will still have my voyager mount, so i am also looking for a short refractor to double up as my portable scope and guider scope in future.
Main Ota at the moment will still be VMC200L until next time i might wanna sell it and get a decent Quadruple APO or Triplet for serious imaging but that probably won't happen anytime soon for the next 1 years i guess.
Considering the loading weight will be quite heavy mostly exceeding 14 kg, were thinking if i should go for heavy duty ones.
In anycase i'm still loading my bullets for the GEM lol

cloud_cover · Post by **cloud_cover** » Wed Feb 16, 2011 5:07 pm

Shirox is mounting a VMC200L, which is a 5kg, 2000mm fl scope and I strongly suspect he wants to go after DSOs.
So you're going to need a mount which is good for AP, many, many factors to consider.
Offhand, I'd say the lightest is the SXD, followed by the CGEM --> Atlas --> G11. Arguably I think the G-11 has the best reputation while the other "premium brand", the SXD is supposed to have mixed reviews about its ability to image, primarily to do with sudden declination jumps of 30-50arcsecs so fast they can't be guided out. Otherwise its +5/-5 Arcsec PE in the RA axis is very nice.
The Atlas is a well known mount for AP but with tuning of the mount and using EQMOD as an add-on guiding solution.
The CGEM is largely unused in Singapore as it natively does not support 0deg latitude but I think its modifiable and there have been folks with good success in AP with the CGEM.
You can get the mounts used from the US, but you bear the risk of undisclosed malfunctions and shipping risk. Do add about USD$300 for shipping
If you want to image with the VMC, seriously consider looking out for the focal reducer as well as thinking of a autoguiding setup

If you're happy doing shorter FL imaging (e.g. Orion will NOT fit in the VMC's FOV even in an FX camera, not to say a Dx camera), good targets will include Omega Centauri, M42, running Man, Flame + HH nebula, Lagoon/Trifid, M6/7 (a bit later in the year) then a lighter mount even such as tim's GP will work with a fast refractor sicne you will be using a much lighter and less bulky scope and can forgo guiding within reason.
To see what targets will fit within your 'scope-and-camera combo's FOV, check out CCDCalc
http://www.newastro.com/book_new/camera_app.php

You can't beat the price!

orly_andico · Post by **orly_andico** » Wed Feb 16, 2011 5:56 pm

Hey look.. I'm in this exact same situation.

My Great Polaris has good +8/-12 arcsec periodic error (20 peak-to-peak) so it's good for AP and I can guide it.. but it can only carry 7 kg.

If you want something with the same level of accuracy (or better) there's the Sphinx SXW (12kg), SXD (15kg).. then the next step up is the G11 already.

The CGEM and Atlas don't regularly hit 20 arcsec PE (some are better, 15 arcsec, some are much, much worse, 40-50 arcsec). The 30 arcsec (+15/-15) CGEMs allegedly can hit +3.5/-3.5 with proper PEC training.

Trouble with the G11 is that if you want GoTo it gets expensive in a hurry (the Gemini 2 computer alone costs as much as a CGEM or Atlas) plus.. Gemini 2 are out of stock everywhere.

If you want something beefier than a G11 but with good accuracy, you're looking at a 6000+ USD mount (Tak EM200, AP Mach1 GTO).

A good choice -- I'd take it if I dared spend that much on the hobby! -- is the discontinued Tak NJP, 30kg payload and goes used for 5000 - 5500 USD.

Well basically if you're only willing to spend $2K to $3K you are limited to the Chinese Trio -- Atlas, CGEM, iEQ45. The last one is available locally for a smidgen under $3K SGD (2200 USD). Not such a bad deal when you consider that the cost of importing one from the US would be about 2100 USD (1600 SRP + 100 in-US shipping + 300 Comgateway + GST).

shirox · Post by **shirox** » Wed Feb 16, 2011 6:39 pm

Yeah man... I probably not so hardcore going for the Epic mounts that will probably have me eating grass instead of my horse lol
So think it will lead me to the same selection as yours. Cos 7kg on my VMC+Diagonal+EP is probably maxing out already.
I'll definitely need the payload.

Between this 2 models apart from the price difference and place of manufacture, any modifications needed to go 1 degree?

shirox · Post by **shirox** » Wed Feb 16, 2011 6:42 pm

wow after conversion ieq45 is going to cost me more than 1000 savings plus it comes with GPS.

shirox · Post by **shirox** » Wed Feb 16, 2011 6:55 pm

Wow there seems to be a 20 page long debate on the reviews of the iqe45

http://www.cloudynights.com/ubbthreads/ ... art/1/vc/1

cloud_cover · Post by **cloud_cover** » Wed Feb 16, 2011 6:55 pm

Actually if your budget is 2-3K you can still get an SXD.
There was a Losmandy G-11 with gemeni for USD2200 but that'll probably be closer to SGD 3.5K after shipping.
I think there's a deal open for a used SXD at USD1600, add about 200 for shipping.
You interested?