I discovered that bin2 images taken with ZWO 2600MC Duo (+ NINA) are 3120 x 2088 instead of 3124 x 2088. 2600MC's bin1 image has 6248 x 4176. So I expected bin2 to be 3124 x 2088. I wonder why there are 4 fewer pixels than expected only in the horizontal (x) direction.
BTW, I found this while trying to convert bin1 flats [1] to bin2 flats using the method used by ZWO. I wrote a script to convert bin2 to bin1, which produced 3124 x 2088. [2] Then, I tried to calibrate light frames with these converted bin2 flats, which didn't work because the image dimensions do not match (lights have 4 pixels shorter in the horizontal direction).
This is not a big deal and I can just drop the rightmost 4 pixels in my script.
I'm posting this just out of curiosity as to why the rightmost 4 pixels are dropped in bin2 images.
[1] (I should have taken bin2 for flats because all my lights were taken with bin2, but I made a mistake of taking flats with bin1)
[2] I'm aware that OSC binning is different from mono binning and I followed what ZWO published about the OSC binning method .
