Dec 11 2025: Website & Forum e-mail infrastructure has been upgraded!
When posting new topics/posts on the forum, the forum response will be much quicker now. All relevant email notifications are still send out as well.
Nov 28 2025:Â APP 2.0.0-beta39 has been released !
Hello. I just picked up a new Askar SQA55. It seems wonderful, except for the dark wedges present in high-magnitude stars. I have checked Cloudy Nights and it seems to be called Aperature Vignetting, or Iron Crosses, and is supposedly common in short, wide, flat lenses. However, the stars aren't impacted just at the edges of the field, as shown in my attached image. The attached pic of IC434 was taken with an SQA55, ASI2600MC Pro, Optolong L-enHance, 60 60sec subs. Any thoughts on how I can address this?
Â
That problem can not be solved with stacking. You have to recheck your equipment. Try shooting with no filter to see if the effect still is there. I thought the SQA55 was superb when it comes to star forms. Never heard of this before on this telescope.
Hi Tyler @monsonmjmgmail-com,
Thank you very much for your question.
Issues like this are usually caused by something in your optical train that is not working as expected. It could be that the SQA55 is not collimated properly, it could also be some adapter or filter that you are using. So I would suggest to try without the filter first like Stefan @digitaliz-se (thanks!) indicates. Maybe the sky conditions even played a part as well, I know that bright star in this object can create problems with O3 filters for example when the moon is shining as well..
APP does not have a function yet, to fix stars with such a cross/pattern.
Mabula
