sbigtopgm

sbigtopgm [sbigfile]

sbigtopgm reads an astronomical CCD image in the native SBIG (Santa Barbara Instrument Group) Type 3 file format and writes the pixel values out as a PGM (portable graymap) image on standard output. When no filename is given, the program reads from standard input.The SBIG Type 3 format is produced by the CCDOPS software bundled with SBIG ST-series CCD cameras. It consists of an ASCII header (with flexible capitalization and tolerant line endings) followed by a 16-bit grayscale pixel array. sbigtopgm preserves the full 16-bit precision of the source, so the output PGM has a maxval matching the original ADU range. Part of the Netpbm toolkit.

There is no pgmtosbig going the other way in upstream Netpbm. The output is always 16-bit even when the camera reports less precision. Astronomy-specific FITS files should be converted with fitstopnm instead.

sbigtopgm was contributed to Netpbm to support amateur and professional astronomy workflows on Unix systems where SBIG's own CCDOPS software was not available. It has remained largely unchanged since its addition.

fitstopnm(1), pnmtopng(1), pamtopnm(1), pnmnorm(1)