ASI533MC-Pro Brightness Issue w/SC 4.1

[MarMax]

I had initially noted this affect in another topic. I'm using Bin2 for these EAA sessions with the C11 @ f/6.1.

viewtopic.php?p=38024#p38024

I've experienced this same thing the past three EAA sessions with the 533MC. The live stack histogram is cut off on the left side, no matter how much Brightness is used. I've had this camera for over two years and until recently never had this issue. Here is a screen grab from last night with the Brightness set to 100 (maximum).

SC_HistoCutoff1_09102023s.jpg (369.33 KiB) Viewed 6750 times

I tried Brightness settings of 10, 20, 40 and 100 and the histogram was cut off regardless of the setting. The zipped log file is also attached. The Gain is 200 for the above screen grab. What is even stranger is when I used a Gain of 350 with a Brightness of 15 (my normal setting), the live stack histogram is not cut off.

SC_HistoCutoff4_09102023s.jpg (394.28 KiB) Viewed 6750 times

[admin]

Hi,

I can see from the log that you had both dark frame subtraction and background subtraction enabled at times during the session. Both might be capable of causing this sort of problem (for instance wrong dark frame, or a background subtraction bug).

The trick to diagnose this would be to drop out of live stacking to the normal histogram if you see the problem - that would be expected to also show a truncated histogram on the left, since the histogram of the individual frames is what feeds through to live stacking.

At that point, start disabling things like dark subtraction and background subtraction and see what causes (hopefully) the issue to go away. If it looks like you are doing everything right (correct dark frames, etc) then please send me if possible some saved frames that cause the problem and I will investigate further.

cheers,

Robin

[MarMax]

Robin,

I finally had a chance to play around with the Preprocessing settings and determined that the issue with the histogram being cut off on the left is caused by the two experimental settings.

Non-Linear Gradient Removal and Low Frequency Wave, when selected, shift the histogram left. I also tested this with several Brightness (Offset) settings and the shift is unchanged with more Brightness (Offset). So for now I'll stop using either of these choices and stick with Linear Gradient Removal or None.

This testing was with the ASI533MC-Pro. I'm not sure what this means but I'm happy to have figured out the histogram shift.

Mike

[admin]

Hi Mike,

thanks for the update - I will check those settings (I have a 533 based camera here, but not the ZWO version). It's odd because they should both leave behind a certain offset level rather than taking things all the way to black. Do you have any of the raw frames saved that I could investigate?

thanks,

Robin