sbigtopgm sbig2ndf /usr/local/physics/sbig2ndf_64bit/sbig2ndf The first step is to get your image into the Starlink Data Format (sdf), this is done using a utility called sbig2ndf. To convert, for example, an image called D_AV_PEG.ST7, the command would be: /usr/local/physics/sbig2ndf/sbig2ndf SBIG=D_AV_PEG.ST7 OUTPUT=D_AV_PEG or you can enter the filenames interactively by just typing the command: /usr/local/physics/sbig2ndf_64bit/sbig2ndf It should be noted that the sbig2ndf program does not like filenames with multiple parts, e.g. D.AV.PEG.ST7, stick to a single name and a single filename ending, e.g. D_AV_PEG.ST7 Do not give any filename ending for the output file, sbig2ndf will automatically do this for you, and gets confused if you put anything there. NOTE: script batch_ndf to convert a long list of files with one command