I have been using ds9 to display images primarily due to inertia. I like the catalog tool for existing catalogs available online; but I wish there were a way to use custom catalog files without RA and Dec (just pixel coordinates) as well. I commonly resort to making ds9 region files, but this requires knowing exactly what you want to see (or filter on) ahead of time.
So three questions arise:
- what FITS file viewer do you use (I am talking about interactive image viewing here, not plotting and saving image files)?
- what is your favorite way to work with catalogs and images together?
- are there hidden interfaces to ds9 for custom catalog types (e.g. image coordinates rather than WCS)?
In your comments, consider adding in how steep of a learning curve you had to climb when learning to use your favorite tools in this area.