Analyse 2:
Two groups of capture:
1) 240 seconds ISO 400
2) 120 seconds ISO 400
Two stacking:
1) only 11 x 240s 400iso
2) 11 x 240s + 21 x 120s
Comparasion between Autosave.tif 32 bits DSS - linear - with magnify of 200x - screen copy by Photoscape. None graphic processing.
photo 1
Comparasion between Autosave.tif 32 bits DSS - autolevel photoshop - with magnify of 200x - screen copy by Photoscape. No other graphic processing.
photo 2
Comparison of histogram
photo 3
note: stacking all photos give appearance of better color of stars, noise reduction, and reduction of "false Airy disk".
Useful if we only want reduce the noise when capturing star cluster with strong stars near to saturation. We don't need 32 photos of 4 min. Only 11 x 4 min e others 21 x 2 min !
Comparison of my normal convertion to 16 bits from Autosave 32 bits - linear - by HDR in photoshop - CS3.
photo 4