Help required mid process :o0

[Jarvo]

Hi All.  Just in the middle of processing a pinwheel and was hoping for some steer from the community.

Much as I try to tweak the levels of my images over several iterations the data gradually gets worse whilst the false colour increases.

Don't worry about vignetting I'm getting a field flattener soon. Its more what is the best way forward to remove the noise and false colour.

Happy for all advice no matter how constructive.

Thanks in advance

Steve

[wimvb]

8 hours ago, Jarvo said:

Don't worry about vignetting I'm getting a field flattener soon.

A field flattener won't do much to reduce the vignetting. You need to take flat exposures for that. A field flattener will remove field curvature. Normally the focal "plane" of a lense is curved like part of a sphere. With a large, flat sensor, you won't reach focus across the entire chip. A field flattener will even out this curvature. But you still have less light reaching the corners of your sensor than its centre. Only flat exposures will correct that.

In your image, you have walking noise. If you dither, ie move the telescope in a random direction, a few pixels between exposures, this will disappear.

What processing software do you use?

[Jarvo]

Hi thanks for the steer. 

I'm using Gimp to process the image. 

Do you need to auto guide to perform dithering. If so that’s another thing I need to master. 

Thanks again

[Jarvo]

Scratch that last question. Looks like I’m off on a journey of dithering discovery 🤢

[wimvb]

This is how I tackled the dithering problem initially. But long term, guiding is what you should look into.