QFitsView is a FITS file viewer similar to SAOimage, DS9, and the like. It was written using the cross-platform QT library and thus runs under Microsoft Windows as well as many flavors of UNIX and MAC OS-X.
QFitsView includes the complete DPUSER - The Next Generation application. For DPUSER, extensive documentation is available, see link below. The graphical front-end (i.e. QFitsView itself) is also documented, and should be quite intuitive to use.
For Microsoft Windows, you need this binary (30 MB).
For Linux, you need this binary (37 MB). Don't forget to make this executable (chmod a+x QFitsView_3.3)!
For Mac OSX, copy this disk image and copy the Application to your favorite location (18 MB). You have to allow execution in the Security & Privacy - General tab of your system settings.
You can also download the documentation in gzipped tar format and extract to your local disk. Don't forget to tell QFitsView where this is (In options->Preferences->Paths)! (This is not necessary for the MAC OS-X disk image which already includes the documentation.)
The combined source code of QFitsView and DPUSER is also available. I strongly recommend using the
binaries because dpuser/QFitsView are depending on lots of external libraries and is not really trivial to compile.
Please understand that I am unable to give any support for compiling.