Bad banding artefacts in my QHY268C CMOS images

[kirkster501]

Hi all,

Produced some good pics with the QHY268C.  However, (without yet another moan about the weather) on my one clear night (or four hours) this winter I grabbed some dodgy data on M67. Beggars can't be choosers when it comes to astronomy in the UK.

Anyway, my dark seems to be very "bandy".  And these bands then pollute the lights.  Rather than removing the [lighter] bands in the lights, the dark makes them worse.  I know the dark is working in other ways since the dead pixels get removed.  Same workflow as I used successfully before so I am not sure what has changed.

I'll need to look further into this when and if we get some more clear nights.  This was the first time I used 120s subs - I normally do 180 - 240s.

What do your guys darks look like please?  Why is mine such a mess?

I am using a quality USB cable that is 1.9m long and have experimented with different USB settings and the banding seems the same.  I use G0 and offset 30.

The final integrated image with the calibrated subs is a line filled mess!!!!

 

Thanks in advance,

Steve

 

 

[kirkster501]

...and this is my workflow.  It worked perfectly with my previous images.  My lights are getting messed up by the dark now for some reason.

[Adam J]

1 hour ago, kirkster501 said:

...and this is my workflow.  It worked perfectly with my previous images.  My lights are getting messed up by the dark now for some reason.

 

How long are your flat frames?

Adam

Edited March 19, 2021 by Adam J

[kirkster501]

About 8 seconds. With flat-darks of the same length.

[old_eyes]

What is your power supply? I had a similar problem with a QHY168C when running off battery if the voltage had dipped a bit.

[kirkster501]

Runs off of a PSU along with rest of my gear. I could try running it off of a battery to check that possibility. Thanks for the thought.

I use a quality USB cable -£16 one - since I know how important cables can be.  The cable bypasses the hub and runs straight to my desktop computer.  I can experiment in that department as well.