Jump to content


CGEM help

  • Please log in to reply
8 replies to this topic

#1 vikan


    Lift Off

  • *****
  • Posts: 16
  • Joined: 05 Oct 2010

Posted 22 September 2012 - 02:16 PM

I have a problem with my CGEM that is messing up my alignment accuracy and possibly other things too.
When i slew the scope using the buttons on the hc , 3 of the 4 directions, up, right and down buttons, work fine. When using the left button it slews fine, but after i release the button, it seems to stop for a second but it very slowly, much slower than the slew rate, still moves for a second or two. While doing alignment if i wait for the extra couple of seconds and center it after that the alignment/calibration gets messed up.

Appreciate your tips.

#2 mich_al



  • *****
  • Posts: 2510
  • Joined: 10 May 2009
  • Loc: Rural central lower Michigan Yellow Skies

Posted 22 September 2012 - 02:29 PM

I can't explain why it keeps moving but someone will come along who can probably. Mine often does the same. Something to keep in mind while aligning is to always end the alignment using the up and right keys at slew rates 2 or 3. Using a high power eyepiece with crosshairs also helps.


#3 vikan


    Lift Off

  • *****
  • Posts: 16
  • Joined: 05 Oct 2010

Posted 22 September 2012 - 02:56 PM

Thanks Al for the tip. I will try it tonight.

#4 Stew57



  • *****
  • Posts: 2571
  • Joined: 03 May 2009
  • Loc: Silsbee Texas

Posted 22 September 2012 - 03:04 PM

It is backlash in the gears. That is why you always finish up and right. The slow continued is the backlash being taken up.

#5 vikan


    Lift Off

  • *****
  • Posts: 16
  • Joined: 05 Oct 2010

Posted 22 September 2012 - 04:02 PM

Would anti-backlash settings help it? Would it come into play while guiding?

While I am at it I might as well get help with a couple of other questions I have, the thread title is appropriate enough. :ooo:

1. DEC balancing. I am able to get scope balanced when it is horizontal, both sides. But I am not able to get it balanced pointing at some angles. All the instructions seem to indicate that the scope should be able to stay balanced while pointing to any portion of the sky. RA is fine. The mount head itself , without the scope on it, doesn't stay balanced at all angles.

2. I was out with the scope last night and got a "no response" message on the HC a couple of times. It worked fine after "undo". Is this a common occurrence ? I was wondering if the colder temperatures could be causing it. How low temperatures can these mounts/controllers work without having problems?


#6 Wembley2000


    Ranger 4

  • *****
  • Posts: 360
  • Joined: 07 Jan 2012
  • Loc: SW Ohio

Posted 22 September 2012 - 05:16 PM

Due to the dovetail clamp being heavier on one side of the cgem, you cannot get perfect balance, it will always try to rotate to were the dovetail knobs point down.

As for the noresponse errors, I had the same problem. I bought a rj11/12/45 crimp tool and just recrimped the hc connector and had no more problems.


#7 rmollise



  • *****
  • Posts: 16040
  • Joined: 06 Jul 2007

Posted 22 September 2012 - 05:49 PM

Ed will probably be along to help you directly, but two things that can cause your "moving" problem are having backlash values set in the HC, and poor balance.

As for "no response," could be HC connectors, could be your power connector,could be your power source.

#8 WarmWeatherGuy


    Surveyor 1

  • *****
  • Posts: 1947
  • Joined: 27 Aug 2011
  • Loc: Orlando, FL 28° N, 81° W

Posted 23 September 2012 - 12:42 PM

If you don't have a way to adjust the weight in two axes then you can't get it perfectly balanced. I have a side-by-side bar that allows me to adjust in two axes. This YouTube video might help.

Complete Mount & Scope Setup. PART THREE (scope balancing)

#9 vikan


    Lift Off

  • *****
  • Posts: 16
  • Joined: 05 Oct 2010

Posted 23 September 2012 - 03:50 PM

Thanks for the suggestions. I was able to solve the dec balancing problem by moving the finder on guidescope to the other side of the axis.

Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics