.FITS

.FITS file extension

This is the basic program to work with .FITS extension

GIMP

GIMP Flexible Image Transport System

GIMP is a free versatile graphics manipulation package. Each task requires a different environment and GIMP allows you to customize the view and behavior the way you like it.GIMP features a great fullscreen mode allowing you to not only preview your artwork but also do editing work while using the most of your screen estate... (more)

The program works with the following extensions: bmp, gif, ico, jpg, png, psd, wmf, jpeg, bw, rs, g3, gbr, im1, eps, tga, gih, pat, gpb, pbm, xcf, im8, pcx, xwd, tub, pgm, dcm, pix, pnm, psp, ppm, als, tif, ras, rgb, fit, cel, sgi, xbm, xpm, svg, im24, im32, mask, tiff, fits, icon, matte, alpha, dicom, bitmap and pspimage

.FITS extension is also supported by the following programs:

Smart Pix Manager

Smart Pix Manager Smart Pix Image

Smart Pix Manager - management and viewing of all types of media files.
MaxIm DL

MaxIm DL MaxIm DL Image

Collects, manages and analyzes astronomical and science data.
Adobe Photoshop

Adobe Photoshop FITS Image File

Adobe Photoshop delivers more imaging magic, stunning creative options and more.