[Garbz (Chris)]

Originally Posted by rally

Chris,

What programs and steps are you using for each step ?

I'm wondering if its an image file format problem.

Unlikely to be a file program. Taking the original FITS straight from the camera and through Pixinsight. I'm using Master Bias and Master Dark libraries like I always have, and I'm using individual flat files taken a few days after I took the light files but without any modification to the imaging train.

Originally Posted by troypiggo

Can you post the master flat stretched with auto STF? You're using a OSC camera? Are you using the BatchPreProcessing script in PI? Screenshots of each tab?

Screenshot of the master flat with an AutoSTF is attached. It's the one of the left. Yes OSC camera. All batch pre-processing. Most values are left at default except that I use overscan correction, master dark and master bias frames. I typically do integration outside of the script and use it to calibrate debeyer and register only, but it's not an integration problem the result is the same regardless of if I use the script or not.

Originally Posted by RickS

What happens if you calibrate a few flat frames with the master flat, Chris? If everything is working as it should that will give you an evenly illuminated result with no visible structures.

You just gave me an idea. I've attached an example with master on the left, original in the centre, and calibrated with the heck stretched out of it on the right. The result shows some problem to the left of the frame but no real issue with vignetting or dust spots. I've calibrated all flats and all showed the same kind of response as the right most image. This could point to a problem with either the darks or the bias frames. I'll do a bit more digging. But what is absent from this picture is problems of vignetting and dust motes which are an issue for the main image.

Originally Posted by LewisM

Seriously, if your sensor is so filthy, CLEAN IT! I really think flats are a lazy excuse sometimes for a clean sensor.

This is the least useful and most DANGEROUS thing you have ever posted. I'm trying to resolve a problem with existing image data and you're suggesting modifying the imaging train potentially destroying every chance I have of correcting that data. I'm happy that you have a perfect imaging system but your suggestion has ZERO to do with the problem at hand. Please stop helping.