SBIG has sold a number of STL11000M cameras which have a major defect:
Vertical banding of weak contrast but visible in each image:
Example:
The distance between the vertical bands is about N=32 pixels (in binning 1 mode!).
My STL11000M camera had been sent back for repair. After 'repair' the vertical banding was less visible but had not disappeared completely.
The vertical bands are less visible in images obtained in binning 1 mode and more visible in images obtained in binning 2 or 3 mode. They dont occur in darks and flats. They are only visible in images with low light levels of the order of 100 to 1000 counts/pixel. The amplitude is of the order of 1.4 counts/pixel in binning 1 mode and 2.5 counts/pixel in binning 2 mode.
As SBIG was sofar not capable to solve the problem on the hardware side and as SBIG refused to make a standard exchange under guaranty with a camera without the defect I was looking for solutions using software tools.
1. Software from ProDigital Software ( by Noel Carboni): Astronomy_Tools: It contains many ( for astronomers ) very useful actions (scripts) for Photoshop, among them one called vertical banding noise reduction which corrects vertical bars. It seems to work quite well but sometimes creates artifacts around bright stars.
2. Software CCDOps5 ( freeware) of SBIG: The newest version CCDOps 5.51 Built-NT contains an option to fix vertical bars. It removes vertical bars efficiently on a majority of the images I have treated with it but not on all.
Attention: CCDOps5 accepts only the original data files created by the camera, but not data files produced later after raw data treatment by other astronomy programs like CCDSOFT, MaximDl, CCDSTACK, DeepskyStacker: CCDOps5 cannot read 32 bit floating point FITS files.
N.B.: A good method to render less visible the vertical bars is to make long exposures of single frames like 20 minutes or longer in binning 1 mode. Binning 2 mode should be avoided.
Even longer exposures are recommended for images taken with narrow band filters ( Halpha etc ).
Links to other web sites talking about vertical banding:
http://astrobug.free.fr/Vertical%20banding%20on%20STL11000.htm
NEW: Bob Franke: BF-Astro Freeware CCDBand-Aid
NEW ( 26/05/2014): Vertical banding is an intrinsic problem of Kodak interline CCD image sensors