Image Data: ds9

For FITS image viewing, there are many choices out there. We use ds9^B.1 as it combines flexible features with a lightweight package. The program gaia has more analysis features (notably point-and-click FWHM estimates), but is much slower, so is inconvenient for day-to-day use. To use ds9, simply call it from the command line. ds9 is fully compliant with the WCS standard.