CGEM all star polar alignment

Gem (Grant) · #1 25-04-2011, 03:28 PM

Hi all,

Are there any CGEM users out there? I haven't noticed any yet. If so, how good is the polar alignment feature? Does it work well enough for imaging?

Thanks!!

Irish stargazer (John) · #2 25-04-2011, 03:38 PM

Hi

I have a CGE but I have updated the firmware to give the all star alignment feature which is the same as on the CGEM. It works quite well, especially if you do a three or preferably four star alignment before the polar alignment routine. I can get 90 second subs with my C11 at F6.3 without guiding and up to five minutes with the Megrez 72 on a good day. Mind you I would love to have a simple polar scope as the electronic alignment takes a bit of time to set up.

Gem (Grant) · #3 25-04-2011, 04:39 PM

Thanks! That CGEM 1100 is looking more and more tempting by the day...

tlgerdes (Trevor) · #4 25-04-2011, 09:31 PM

Stuff the fancy "all star polar alignment"

.

If you are going to image, learn how to drift align as a minimum. It will take you slightly longer but the results are 100% better.

5min subs with guiding, that shows you how "useful" it is.

toc (Tim) · #5 25-04-2011, 10:18 PM

Quote:

Originally Posted by tlgerdes

Stuff the fancy "all star polar alignment"

.

If you are going to image, learn how to drift align as a minimum. It will take you slightly longer but the results are 100% better.

5min subs with guiding, that shows you how "useful" it is.

The all star system will get you close and that will make it a lot quicker to do a drift align.

TrevorW · #6 26-04-2011, 12:09 AM

You know the mount is nothing more than a Celestron badged EQ6, they both come out of the same factory

seeker372011 (Narayan) · #7 26-04-2011, 12:53 AM

Yes they do come out of the same factory.some of us have seen them being made there when we visited the factory. The CGEM is not a rebadged EQ6
The CGEM is a completely different mount..for one thing the software is superior
The any star polar alignment is a superb feature that cuts polar alignment time down enormously

I used to get 20 minute guided subs at 600 mm focal length with a CG5,which I believe to be mechanically inferior to a CGEM. I used at least a 6 star alignment before polar aligning usually

Gem (Grant) · #8 26-04-2011, 07:10 AM

Thanks everyone! Much appreciated.
Anything that will save time night by night is a good thing methinks.

tlgerdes (Trevor) · #9 26-04-2011, 07:30 AM

Quote:

Originally Posted by toc

The all star system will get you close and that will make it a lot quicker to do a drift align.

How long does it take you to drift? I can get it done in 20mins using a compass, PHD and my guide cam.

If you add an "All Star" routine I don't see it getting quicker.

My G11 has something similar, when I bought it I thought great, it will help me polar align, but after learning to drift, I have never learnt how to use it.

It is like those new fangled cars the can reverse park themselves. Great idea, until you have to drive a car without it and find you can't reverse park.

toc (Tim) · #10 26-04-2011, 09:51 AM

Quote:

Originally Posted by tlgerdes

How long does it take you to drift? I can get it done in 20mins using a compass, PHD and my guide cam.

If you add an "All Star" routine I don't see it getting quicker.

My G11 has something similar, when I bought it I thought great, it will help me polar align, but after learning to drift, I have never learnt how to use it.

It is like those new fangled cars the can reverse park themselves. Great idea, until you have to drive a car without it and find you can't reverse park.

Personally I hate doing a drift alignment. I freely admit that Ive only really started to master it, but the thought of having to do it really kills my enjoyment of the hobby. Last time it took me 2 hours

casstony · #11 26-04-2011, 10:00 AM

I've read comments that the CGEM uses noisy servo motors whereas the EQ6 uses silent steppers - is that correct?

As much as I like the Celestron hand control/software I don't like noise.

marki · #12 26-04-2011, 12:13 PM

Or just use alignmaster, takes two minutes and you are close enough to the pole to image with a guider.

Mark

tlgerdes (Trevor) · #13 26-04-2011, 01:04 PM

Quote:

Originally Posted by toc

Personally I hate doing a drift alignment. I freely admit that Ive only really started to master it, but the thought of having to do it really kills my enjoyment of the hobby. Last time it took me 2 hours

If it is taking you 2 hrs, you are doing it the hard way.

Here is link to PPT I produced for ASNSW

ftp://sarcasmogerdes.dyndns.org/down...HD-graphs.pptx
Ingredients: Compass, Guide Scope, Guide Cam, PHD Guiding and 20mins

toc (Tim) · #14 26-04-2011, 03:58 PM

Quote:

Originally Posted by tlgerdes

If it is taking you 2 hrs, you are doing it the hard way.

Here is link to PPT I produced for ASNSW

ftp://sarcasmogerdes.dyndns.org/down...HD-graphs.pptx
Ingredients: Compass, Guide Scope, Guide Cam, PHD Guiding and 20mins

Wow, thanks for that. Im short of the guide scope and guide cam at the moment, otherwise I would try it on my new setup, when I do get a mount. Could you do this with your main scope, rather than with a guide scope?

mithrandir (Andrew) · #15 26-04-2011, 04:41 PM

Quote:

Originally Posted by toc

Wow, thanks for that. Im short of the guide scope and guide cam at the moment, otherwise I would try it on my new setup, when I do get a mount. Could you do this with your main scope, rather than with a guide scope?

No reason why not, but I would not like to try it with a DSLR or CCD which has a shutter. Shutters only have a finite lifetime. Any webcam supported by PHD would work, but any cam without an ST4 port would require a serial interface to do the guiding. Celestron's handsets, for example, have serial ports. Some others need something like EQMod.

If I put my guide cam on the main scope it would give 0.75 ASP. Since it's 5 times the focal length of the guide scope, it is 5 times as sensitive to tracking errors.

Hmmm. Maybe that's as good a reason for getting an OAG as I've seen.

Andrew