Upgrading my mount ... and everything else

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  • Member since
    November, 2013
Upgrading my mount ... and everything else
Posted by Bradicus on Saturday, November 09, 2013 9:11 PM

I’ve been out of the astrophotography hobby for a while now, but I think I’m ready to jump back in.  Up until now I’ve had pretty good luck using a DLSR on my C8-SGT.  I’m looking at upgrading all this equipment with the intent of trying my hand at narrowband imaging to combat the less-than-dark skies I find myself in now.

The basic setup I’m looking at is a new mount (the root of the question to come), a 4” class APO (perhaps the Stellarvue SVR102T-25) and an STF-8300 CCD with the autoguiding package.
So … the first step in this upgrade will by my mount.  The CG-5 has worked OK, but I know I won’t be able to get the longer exposures needed for narrowband imaging.  My primary complaint with this mount has been very poor tracking in lower temperatures (almost worthless once the temp drops below about 20F) and poor DEC autoguiding.
I’m currently going back on forth on the CGEM and the Atlas.  I am aware of the issues the CGEM has had (including the DEC cogging issues … has it been fixed?), but I’m unfamiliar with the Atlas interface or any of the quirks that it may have.  One of the great successes I’ve had with the CG-5 has been the polar alignment routine.  I can run through a 2-star alignment (followed up with 4 calibrations stars) and a computer assisted polar alignment and be close enough to get 5 minute exposers at 1200mm with no star trailing.  Simple and effective.  The ability to continue this routine is really pushing me toward the CGEM.  Does the Atlas have a similar polar alignment routine that is even close to as accurate and easy?
I know … I know … I need to be doing drift alignment.  I realize this will be required as I push to 10 and 20 minute subs, but I would like the process to be as easy as possible.

Any comments on either the CGEM or the Atlas would be greatly appreciated.  I would especially love to hear whether the CGEM DEC cogging issues has been resolved (the last comment I can find on a pending firmware update was 6 months ago).  I’m also completely open to other mount recommendations, but please keep in mind that I need to keep budge in mind.

  • Member since
    July, 2003
  • From: Eastern SD.
Posted by johnjohnson on Saturday, November 09, 2013 11:07 PM

Hello BioAstro

This debate still goes on on many forums. Each mount has it's pro's and con's. If you use a laptop while you are imaging then the Atlas has many strong points. EQMOD software with ASCOM controls allows for polar alignment, and the latest release of V3.35 Synscan hand control also has a polar alignment routine. Many people like the Celestron HC software better than the Synscan. I have used both and have no preference. The Celestron offers many features but in actual usage few of them are used. I find the Synscan to be simplistic. It offers only what is needed and is very basic in it's functions. The use of EQMOD with an Atlas or EQ-6 gives it the edge. EQMOD integrates with so many other softwares that it is way beyond the capabilities of the Celestron HC.

Here is a link to another forum. They also discuss some of the pro's and con's. Hope this helps with your decision. Either way you go you will be getting and excellent mount for a 4" instrument.

CGEM-DX vs. ATLAS

(that thread has 4 pages. switch pages at lower left of each page or chose show all)

JJ

20" F5 Obsession, OMI mirror .987 Strehl. 10" F4.7 reflector. 6" F5 ST reflector. 120mm F7.5 EON. 80mm F11.3 guide scope. SkyWatcher EQ-6 Hyper Tuned.   Flicker Astro Site   More Astro Images

  • Member since
    November, 2013
Posted by Bradicus on Sunday, November 10, 2013 10:21 PM

After a weekend of reading, I am leaning toward the Atlas.  I'm still not 100% though.  Relative to the NexStar, how difficult is it to do a computer assisted polar alignment with EQMOD/Synscan?  My imaging time is extremely limited.  I simply do not have the time for multiple hours working on my polar alignment each time I decide to do some imaging.  I need this process to be as easy as possible.  As I mentioned before, the CG5 with its polar alignment routine got me close enough to do 5 minute subs with no drift alignment.  I realize that to get to 10 minute subs I will be doing some drift alignment, but I really need that initial alignment to be as good as possible.

I do see a lot of possibility in EQMOD.  I’m just not sure how much of it I would use.  Aside from a polar alignment and a quick goto, the rest of the night is spent actually capturing photons.  I use PHD to guide the scope and image capture software (currently DSLR Shutter … looking to move to Nebulosity … the SBIG will probably bring in a whole new software package) to control the camera.  That doesn’t leave a lot for EQMOD to do.

Looking for some convincing here  J

 

  • Member since
    July, 2003
  • From: Eastern SD.
Posted by johnjohnson on Monday, November 11, 2013 7:04 AM

BioAstro

The polar alignment routine is very similar to the Celestron. Very much like a drift align but without the reticle eyepiece. Here is a link to the SynScan hand control manual. Polar align is on page 35. I have a polar alignment scope and use auto guiding when I am imaging so I very seldom do this alignment routine. Not very complcated though. Peruse the manual and compare it to your Celestron. They are similar some what. Both are made by Synta so there are some similarities.

SynScan

 

I checked the Nexstar PDF and if this is what you are doing for a polar alignment it can also be done with the Synscan. You will just have to choose bright stars and pick Polaris, then go to it and make the adjustments just as with the Nexstar but not pressing enter key. I would then do another alignment.

From the Nexstar manual.

" 2. Select Polar Align from the Utilities menu and press Enter.
Based on your current alignment, the telescope will slew to where it thinks Polaris
should be. Use the equatorial head latitude and azimuth adjustments to place Polaris in
the center of the eyepiece. Do not use the direction buttons to position Polaris. Once
Polaris is centered in the eyepiece press ENTER; the polar axis should then be pointed
towards the North Celestial Pole."

JJ

20" F5 Obsession, OMI mirror .987 Strehl. 10" F4.7 reflector. 6" F5 ST reflector. 120mm F7.5 EON. 80mm F11.3 guide scope. SkyWatcher EQ-6 Hyper Tuned.   Flicker Astro Site   More Astro Images

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