Jump to content


Trailing stars problems

Recommended Posts

Can anyone shed some light on what might be causing the trailing stars even at short exposures of 20 seconds?

Here's 2 images from the beehive cluster, 1 showing trails at 30 secs and another which looks ok at 3 mins. Seems to be intermittent.


Grateful for some help




Link to post
Share on other sites

The short exposures were not guided, i was taking short test shots to make sure I had the target in view.

There was more than 1 image that had trailing and I was stood away from the scope. I also had it with some of the 3 minute exposures. Could they all be because of cables hanging down?

Does the fact I had a mix of good and bad point to a tracking issue or make it less likely?



Link to post
Share on other sites

Knocked, wind, periodic error (quite harsh one), balance issues and backlash? The cables could be a cause too. Best to attach them as much as you can to the telescope, with them still being able to move as the telescope slews/tracks.

When I got my Celestron AVX mount, I often saw star trails, more often with longer exposures, logically, but not always. And I found out that it was because of periodic errors in the wormgear.
The AVX has Periodic Error Correction learning, and after I did that, and applied it, I went from having to scrap every 2-3 frames, to being able to do 4-5 minute exposures without guiding, as long as polar alignment was very good.

Might not for certain be the issue here though.

Link to post
Share on other sites

Looks indeed like a balance issue or a gear skip problem in the mount: if the weight is not well balanced (or TOO well balanced) the mount might skip one gear tooth from time to time, which gives you the tiny line to the side you see. Depending on how big/small the issue is it could only pop up every couple of minutes or so.

Link to post
Share on other sites

OK, I'm not an expert by any means. On the first image the "trail" is exactly in line with the spider star lines. On the second image , the spider lines are there (but rotated from the original) and no "tailing". Could it be a reflection off the spider in the first image and you have re-positioned the Scope on the second image hence no reflection?

The 2 images are inverted from each other. Did you have a meridian flip?


Edited by Spitfire
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.