Jump to content


Photo

polar alignment question

This topic has been archived. This means that you cannot reply to this topic.
9 replies to this topic

#1 donnie3

donnie3

    Mercury-Atlas

  • -----
  • Posts: 2712
  • Joined: 15 Dec 2004

Posted 29 March 2009 - 08:46 PM

im just getting into astrophotography and have a cg-5 mount with drive. the area i observe in is very small and i have to look over trees and roof tops. i cant really get a good alignment with drift or any other method. my question my be wishful thinking but i was wondering if there was a mount that you could polar align electronicly like gps or something of that nature. thanks, don

#2 mclewis1

mclewis1

    Thread Killer

  • ****-
  • Posts: 11064
  • Joined: 25 Feb 2006

Posted 29 March 2009 - 10:18 PM

Is your CG-5 a goto mount? If so I'd consider upgrading (if possible) your hand controller firmware to the latest gem 4.15. You need to be at 4.xx to be able to do an upgrade to the firmware ... if your hand controller is using 3.xx then you'd have to replace with an upgradeable one. With 4.15 there is a new All Star Polar Alignment routine which will allow you to choose from a variety of stars to perform the polar alignment of the scope. Even with a quite well obstructed sky you should be able to find stars to do this new polar alignment.

The user guide for this new version is the CGEM user guide available on Celestron's website. For additional info on the firmware upgrades have a look at Mike's site http://www.nexstarsite.com/

#3 donnie3

donnie3

    Mercury-Atlas

  • -----
  • Posts: 2712
  • Joined: 15 Dec 2004

Posted 29 March 2009 - 11:10 PM

mclewis1: my cg-5 isn't a goto, it just has a ra drive motor. i don't know anything about goto so what your saying is that you can use some type of system to track good enough to do ap for say, 1-3 minutes. how does this work, does it use gps or is it built in to the locating system. do you have to level the mount etc. hope im not asking too much. i sure would like to have a mount that have this function but knowing how expensive this astro equipment is i would like to know a little about what im buying before i lay down the $. thanks, don

#4 Alph

Alph

    Surveyor 1

  • -----
  • Posts: 1769
  • Joined: 23 Nov 2006

Posted 30 March 2009 - 12:26 AM

my question my be wishful thinking but i was wondering if there was a mount that you could polar align electronicly like gps or something of that nature.



Have you considered Meade ETX-LS?

#5 donnie3

donnie3

    Mercury-Atlas

  • -----
  • Posts: 2712
  • Joined: 15 Dec 2004

Posted 30 March 2009 - 11:34 AM

alph: i pulled up some spec, online about this meade product. it sounds like just what i need but the only problem is, i dont need the scope or camera. i have too many scopes as it is, 6 and 8" sct, 3 refractors, 4 reflectors. ccd,s and a canon xsi so all i really need is the mount. i wish that the mini cube had that kind of advanced tech, i would probably have my order in right now. thanks for the reply. don

#6 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15764
  • Joined: 06 Jul 2007

Posted 30 March 2009 - 11:38 AM

Have you considered Meade ETX-LS?


At this juncture, that would NOT be a scope I would consider if imaging was a priority.

;)

#7 mclewis1

mclewis1

    Thread Killer

  • ****-
  • Posts: 11064
  • Joined: 25 Feb 2006

Posted 30 March 2009 - 11:44 AM

Goto and good tracking are two different animals ... for your interest in imaging with your EQ type of mount you need to be reasonably well polar aligned ... the better your polar alignment the longer your exposures can be without the star images starting to trail.

With all the electronic smarts Celestron has built into the goto capable mounts they have also added a neat little feature that really helps doing physical polar alignments, especially for folks who can't use Polaris. That's what I was referring to when I mentioned the All Star Polar Alignment routine.

There are lots of different goto capable mounts ... some have GPS some don't. Having an accurate location isn't going to help you with your polar alignment issue, you still need to have the mount accurately aligned (regardless of it's relative location under the stars). If you feel you can't use any of the drift alignment routines then I'm sorry but I'm at a loss as to how you can proceed for imaging with your manual mount. I have heard of folks who have setup a physical reference point (light, fence post, etc) when they can't see Polaris but I believe that this is based on getting at least one accurate polar alignment done. Perhaps someone who's done this can chime in and explain it.

#8 neptun2

neptun2

    Viking 1

  • -----
  • Posts: 986
  • Joined: 04 Mar 2007

Posted 30 March 2009 - 02:33 PM

CG-5 is identical to EQ-5. The goto model of EQ-5 can be polar aligned using one, two or 3 stars. At least one of this methods can be applied in your case after making rough polar alignment by pointing the polar axis to north using compas and setting the altitude on the mount. Of course using only one star the polar alignment will not be very precise but if it will be good enough for some short exposure photography i can't be sure. Your mount can be upgraded to goto model by replacing the motors, hand controller and one electronics board but this is rather expensive solution. See here:
http://www.opticalvi...d_goto_upgrades

Look for SynScanTM GO-TO UPGRADE KITS
Upgrade Kit for standard EQ5

#9 Sergio Porres

Sergio Porres

    Lift Off

  • -----
  • Posts: 24
  • Joined: 02 Jul 2007

Posted 30 March 2009 - 07:08 PM

I had the same problem, And I dont see the polar star,

If you want a simple procedure, you have to know your latitude, because is the measurement from the horizont to the north.

After that, with a compass you can identify the magnetic pole, and the real north is 10 degrees to the east.

This is a regular alignment.

#10 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15764
  • Joined: 06 Jul 2007

Posted 31 March 2009 - 09:02 AM

CG-5 is identical to EQ-5. The goto model of EQ-5 can be polar aligned using one, two or 3 stars.


Actually, they are far from identical. The CG5 uses entirely different motors, computer, and firmware.

You don't use several stars to polar align the CG5, you either use Polaris (older firmware) or you use ONE star of your choice (AllStar Alignment). This is distinct from the go-to alignment, where the CG5 uses from two to six stars (two alignment stars and up to four calibration stars).

;)






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics