Hello Siril experts,
I captured 197 light frames of Andromeda from Sollentuna in Sweden.
- Canon EF 135 mm F/2.0 @ F/2.0, 2 seconds, ISO 800, RAW (CR2), Long exposure noise reduction (dark frame subtracted in camera)
- Canon 5D mk IV
I also captured flat frames:
- 1 second, ISO 100, Long exposure noise reduction
I have Siril 0.99.4 Beta.
When I try and perform flat field compensation to remove vignetting I get overcompensation.
How to import the RAW files into SIRIL and use the flat frame to remove vignetting?
A subset of 20 frames (of 197) are here:
My attempt at a workflow for this case:
Note: If Cal = (Lights - master-dark - master-bias)/(master-flat - master-bias) I assume that my lights are already (lights - master-dark - master-bias) since I have used an in camera dark frame subtraction. The same comment applies to my flats, ie my flats are (flats - master-dark - master-bias)
1: convert flats, stack flats median with multiplicative normalization to get master-flat.
2: convert lights, preprocess lights with master flat and Debayer (no dark, no bias selected).
3: Register preprocessed lights, stack preprocessed lights.
My master-flat from step 1, is here:
An example of a preprocessed light frame from step 2, is here:
- I might have created: Cal = (Lights - master-dark - master-bias)/(master-flat - master-dark - master-bias), since both lights and flats are RAW with in camera dark frame subtracted. This is NOT the original equation. Is this the root cause of my problems? I need new flats without in camera dark subtraction?
- What is the best process, in my case, with RAW frames with “in camera dark” subtracted from light frames and flat frames?
- Is the only possible work flow with Siril to have all of bias, darks, flats and lights (and no in camera dark RAW subtraction)? This is what I have seen in tutorials.