Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_celestial_motion.thumb.jpg.a9e9349c45f96ed7928eb32f1baf76ed.jpg

Ccolvin968

Tracking issue? Out of focus? Need a little help...

Recommended Posts

So I got my new tracking mount out again tonight. 

As far as I can tell with my limited knowledge of AP, the mount is tracking fine.

As long as I stay at "normal" image size, the stars look crisp and like a point.

Once I zoom in on them (to the point of some pixilation) I notice a slight streak running from the star to the left.

Is this a tracking issue or do I just need to focus better?

I also just noticed that I left the Image Stabilization on... Is that good or bad if it's on a tracking mount. I'm guessing bad?

I've attached the test shot from tonight.

You'll find M31 at the left edge, Cass to the right, and super faint (unless I lighten the image to the point it's ruined) you can see the double cluster as well. You'll see what I'm wondering though. zoomed out, point like stars. Zoomed in, a tiny bit of smudging... Any ideas or suggestions?

Also, any good references on doing post in photoshop?

Thanks for any help!

post-31252-0-10938900-1453172721_thumb.j

Share this post


Link to post
Share on other sites

Turn IS off when using a tripod or mount yes. It looks to me like bad tracking possibly from slightly wonky polar alignment. The stars are all the same all over. Are you auto-guiding using a guide scope and guide camera? If so try drift aligning the mount using PHD2

Share this post


Link to post
Share on other sites

I'm using an iOptron Skytracker so it's the basic setup. I'm using the included polar scope and aligning it where my phone app tells me to. I just have a camera attached to that and a 28-135 lens set at 28mm. Maybe I just need a little more practice with getting polaris smack dab in the same spot or just learn what I need to do to get these to go away... These are 10 second exposures and the above image is a stack of 207 images. Not sure if temp matters, but it was around -4* F when I was shooting. I'll turn off IS from now on then... Dumb me. 

  • Like 1

Share this post


Link to post
Share on other sites

Looks like lens abberations to me..

You have some round stars in the middle, so tracking seems ok.

Turn off IS  and enable mirror lockup, if you can, and then see if that makes a difference.

If not then it's likely abberations, I can see some chromatic issues new the corners.

If your only doing web sized images then I would'nt worry but printing big won't look good.

BTW focus seems quite good.

Edited by wxsatuser

Share this post


Link to post
Share on other sites

Also use an intervelometer and don't forget to leave a few seconds in between for things to settle. 

Share this post


Link to post
Share on other sites

Focus on a star around the thirds intersection from the edge is worth doing as well.

Share this post


Link to post
Share on other sites

Thanks everyone for the advice. I'll put a 3 second delay between my shots on the intervalometer. I also forgot I left the UV filter on as well. That's probably where the aberrations are at. I'll try to fix all of the above and post my results once I get them. After I get this down I'll start trying to zoom in a bit and get actual landscape and Milky Way shots. Again, thanks for your help!

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.