siril dslr processing

 EOS/Ti and dslr-in-general users. It's always going to be a compromse, so keep it simple.

Forget about in-camera bias and dark frames. They'll introduce further artefacts, noise in particular. Instead, simply subtract the offset (often misleadingly called bias) [1] as follows. 

Here I'm using a modern EOS with an offset of 2048. Earlier models [2] used 1024.

1. Calibration of flat frames

Convert all your raw files to fits files using Siril's Conversion tab

Load the flat frame sequence.

Calibrate as follows:

Now stack to get the master flat frame. The default is:  pp_flat_stacked.fits

2. Calibration of light frames 

Load the light frame sequence, then, leaving the bias value intact, include your newly stacked flat frame from (1) above:

Don't forget to check debayer.

Register then stack.

That's it.

[1] How do I find or check the offset?

• Take a raw frame in total darkness with a shutter of 1/4000s or 1/8000s
• Convert it to fits using the conversion tab
• Open in Siril
• Tools -> Image Analysis -> Statistics (on older versions: right click the image -> Statistics)

The origin of the 2048 should now be self explanatory

[2] 450d and older. There maybe others, but it's easy to check as above anyway.