We need a little more information.
Is the thumbnail image you posted a single Dark frame or is that a Master Dark frame stacked from many individual frames?
What exactly is the issue with your Light frames after calibration?
As others have already mentioned, the starburst glow patterns at the right center and upper left are due to "Amp Glow" -- essentially IR radiation from a portion of the sensor itself. That is completely normal and should calibrate out when Dark frames are applied to the Light frames. The calibration should remove this completely. If it doesn't, we would need to more lots more about your calibration methodology -- which software you use, how was the Master Dark prepared, whether the Dark frames matched all capture parameters with the Light frames, etc.
If, on the other hand, you are asking about the dark horizontal lines in the Dark frame, this is another common question about this camera. There are quite a few threads here on CN about the Dark Banding issue and how to minimize or eliminate it.
Tell us more about your concerns and perhaps we can steer you to a remedy.
By the way -- Welcome to Cloudy Nights! I see this is your first post although you have probably been reading for a while judging from your join date.
Oops, I just noticed that you are using the OSC version -- ASI294MC-Pro. My mistake -- I thought you were asking about the monochrome version at first. The ASI294MC-Pro camera does not usually show the dark banding issue seen in the ASI294MM-Pro (a totally different camera in spite of the similar name).
The starburst glows you see are totally expected and with proper application of Master Dark frames, should never show in your calibrated Light images.
Edited by jdupton, 16 May 2021 - 11:52 AM.