BIN compresses images by integer factors. Adjacent pixels are added together.
Use BIN= to specify a single compression factor for both rows and columns,
or use BINR and BINC to specify the compression for rows and columns
individually. For spectra, just use BIN. Note that
NORM makes the program AVERAGE adjacent pixels when compressing the image, instead of the default summing of pixel intensities.
BSR and BSC specify the starting row and column, respectively, of the region being saved. These are pixel locations in the original image. They are used to compress and save only part of an image.
The output image ALWAYS has starting row 0 and starting column 0. It does not make sense to use BIN on a wavelength-calibrated spectrum.