photographing issue

[MissErin]

Hi all,

Attached is an image I took of Eta Carina a few nights ago. I tried to stack the images using programs Registax and Deep sky stacker, however the stars on the left hand side of the image wouldnt stack properly and instead looked like they had a trailing effect, whilst the stars over the rest of the image were fine. I then stacked the images myself manually using Adobe Photoshop CS2 and got a better result, but still with slight blurring of stars on the left hand side of the image.

Any suggestions as to what could be causing this on just one side of the image? Im relatively new to astrophotography so please don't get too technical!

[rcheshire (Rowland)]

Erin. Looks like the camera is not fitted in-line with scope. Maybe DSS has issues when trying to align long stars. Nice job otherwise.

[Eden (Brett)]

Hi there Erin,

Could you please tell us what camera, telescope etc you used to take this image? Having that information will help troubleshoot the problem.

[leon]

Erin, I think Rowland might be right, and would check out the camera alignment first, it dose not need much to be out.

Leon

[MissErin]

Ah yes, I should have definitely been a little more specific

The image was taken with a Celestron 9.25" SCT on a CGEM Equatorial mount. The camera was a 6D connected by the T ring and 2" barrel, which was connected to Backyard EOS. I stacked 14 images at various exposures, over a total duration of about 15 minutes.

I am pretty new to the field of astrophotography so this is all a learning curve, but I think I have almost conquered telescope/polar alignment issues that I once had. I'm just left scratching my head a little on this image.

If the issue does fall within the camera setup, how would I go about fixing the issue? (sorry for the questions- bear with me)!

-Erin

[Slawomir (Suavi)]

Hi Erin,

I have no experience with imaging with SCTs, but it does look like optical misalignment, often sagging focuser is to be blamed for that.

However, stars not matching perfectly across the image may be also caused by field rotation between subs due to inaccurate polar alignment. When stacking images, I always correct for field rotation and have found this method gives very good results. I know that Nebulosity and PixInsight can correct for field rotation, but have not used DeepSkyStacker and Registax only a few times ages ago, so I cannot comment of their capability to correct for field rotation.

Good luck and let perseverance and patience be your best friends

[ralph1]

Originally Posted by rcheshire

Maybe DSS has issues when trying to align long stars.

Yes, for me DSS has major issues aligning elongated stars, it just produces a fuzzy mess.