Star elongation issues across multiple imaging nights

Equipment Acquisition Artifacts Collimation Coma Help Needed Troubleshooting
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Brett Joslin avatar
Brett Joslin avatar

Hello

I have been struggling with my Bisque MyT , a Celestron Edge HD 11”, Player One - filter wheel OAG Camera, and an older version Moonlite CHL 2.5” focuser. this is the first time I have a full setup with all of these items and have been struggling for a long time. I have worked through most issues and now I am finally imaging and having an issue with my stars. Not sure if they are elongated or considered tear shaped. The three images provided show the star shape which were taken two different nights. The star shape is the same throughout the entire image going in the same direction but they go in different directions between each night. what do you think it is? Hope I can get this fixed.

📷 LUM_April.jpgLUM_April.jpg📷 LUM_April2.jpgLUM_April2.jpg📷 HA_March.jpgHA_March.jpg

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Tony Gondola avatar
Tony Gondola avatar

It’s guiding/tracking error. What does the software side of your setup look like?

Brian Puhl avatar
Brian Puhl avatar

If the trailing is consistent through the entire image (verify using abberation inspector), then you are likely having a guiding issue. Check the direction of travel against a sky map with RA and DEC overlaid, like Stellarium. Chances are one direction is right ascension and the other is declination.

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Brett Joslin avatar
Brett Joslin avatar

Thank you. I failed to tell you that I am using the SkyX and NINA. the guiding seems to be off like my RA was drifting at one point and at 2.14. I looked up issues between both softwares and fixes and it didn’t seem to work.

Tony Gondola avatar
Tony Gondola avatar

I know nothing about SkyX so someone using that will have to chime in here….

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Brett Joslin avatar
Brett Joslin avatar

Tony Gondola · Apr 16, 2026 at 02:25 PM

I know nothing about SkyX so someone using that will have to chime in here….

you would only use the SkyX to a get a TPoint model (mathematical model of your scope and imaging train for better guiding) and accurate polar alignment then everything will be run through NINA. So you would be using an ASCOM connection to TSX but would be guiding with PHD2.

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Tony Gondola avatar
Tony Gondola avatar

Then the question to ask would be, what do your PHD2 guiding graphs look like for the session in question?

Jeff Bennett avatar
Jeff Bennett avatar

I too would guess it is a guiding issue. I don’t have a Bisque mount, but since you re using PHD, did you try to recalibrate PHD guiding? Did you get a good calibration? I would guess it’s a simple issue. Also, make sure your polar alignment is within 5” or less.

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