Hi there, I am following the manual preprocessing tutorial for my first time working with calibration shots and got a bit confused when I got a 1 - 2% rejection rate while stacking the biases. A quick google search revealed that the 0.1 - 0.5% rejection rate mentioned in the tutorial seems to be outdated, I could not find any suggestions on what rejection rate seems acceptable when stacking calibration shots.
Now I’m encountering a 6% rejection rate when stacking flats:
17:48:23: Starting stacking...
17:48:26: Pixel rejection in channel #0: 1.935% - 1.506%
17:48:26: Pixel rejection in channel #1: 3.191% - 2.838%
17:48:26: Pixel rejection in channel #2: 23.675% - 6.345%
17:48:26: Rejection stacking complete. 128 images have been stacked.
17:48:26: Integration of 128 images on 128 of the sequence:
17:48:26: Pixel combination ......... average
17:48:26: Input normalization ....... multiplicative
17:48:26: Output normalization ...... disabled
17:48:26: Pixel rejection ........... winsorized sigma clipping
17:48:26: Rejection parameters ...... low=3.000 high=3.000
17:48:26: Creating rejection maps ... no
17:48:26: Image weighting ........... disabled
17:48:26: RGB equalization .......... disabled
17:48:26: Background noise value (channel: #0): 20.363 (3.107e-004)
17:48:26: Background noise value (channel: #1): 21.678 (3.308e-004)
17:48:26: Background noise value (channel: #2): 21.848 (3.334e-004)
17:48:26: Saving FITS: file pp_2024_07_06 Saturn_2 flats_stacked.fit, 3 layer(s), 1920x1080 pixels, 32 bits
17:48:26: Execution time: 5.12 s
Is this still acceptable?
Further notes:
I am shooting with an astromodified DSLR (EOS 77D) that has about 10.000 shots. 128 Shots where each taken for flats, darks and biases. I have stacked the biases using Average stacking with rejection, no normalisation, winsorized sigma clipping (3.0 for both low and high sigma). Flats where calibrated using the master_bias before stacking - short: I followed the tutorial as best as I could…
Images were taken using the 77D’s time lapse function, which provides an .mov file instead of a pure RAW-image - could this be the culprit? (ISO 1600, 1/50 exp, 1 shot / second).