Stars not round

hogann

My star images are never perfectly round. I always get side lobes on all the bright stars in my image. The side lobes appear in the direction of the field drift. In some part of the image, the lobes are on one side of the star. In other parts, the lobes appear on both sides.

I took intentionally out-of-focus images and see that the diffraction rings are centered and round.

I am using the firmware version 1.12. The Seestar is level to better than 0.4 degrees.
The stacking process is very efficient. I rarely get any dropped images due to failed tracks.

Can to suggest how to get round stars ? I was imaging M81 and M82 from 41degrees north latitude.
I'm uploading two images for illustration.

Thank you for making this wonderful product.

AstroImg@ZWO

hogann Sorry for bringing you a bad experience. You can check the single image taken before superposition. It may be that an image of a drag line has been superimposed.

hogann

I am finding that the side lobes on the stars is affected by the levelness of the Seestar.

When I put the Seestar on a level table and calibrate the Seestar's digital Level, the digital calibration does not go to 0.0 degrees. It stays at 0.3 degrees, which is weird. Can I put a small bubble level on the horizontal surface of the Seestar's platform and use this bubble level to adjust the Seestar ?

Maybe in a future release, it would be nice to allow less than 10 second exposure in order to keep the stars nice and round.

AstroImg@ZWO

hogann You can use a level bubble meter to calibrate the level sensor to ensure the level of the level sensor. The detailed operation process can be found in Seestar's tutorial

hogann

AstroImg@ZWO Despite my best effort at leveling the scope, I cannot get the stars to be round. All my bright stars have a tail. Can you suggest how to check the collimation ? Perhaps I need to send it back for repair ?
Thank you.

AstroImg@ZWO

hogann If you need to return it for repair, you can contact support@ seestar.com. I'm sorry for the trouble it has caused you.

hogann

Hi everyone, I just want to say that this has been resolved. It is either an imperfection on the edge of the lens or some thing cutting into the aperture. So by reducing the aperture with a ring or something similar, I get nice round stars.

Actually I experimented first with masking off the edge and got really beautiful diffraction spikes.

Hope this helps people who are wanting to improve the image.

tech49

Awesome hack, and I love the effect on the star images.