Radio Eyes Help
Quite frankly, the world of radio source catalogs is a big mess!! There are hundreds of catalogs of radio sources, many containing thousands of sources and some containing just a few special sources from specific regions. The position and flux accuracy varies greatly. In some cases, galactic plane objects have been excluded. It is a confusing situation.
One simplifying factor of amateur radio astronomy is that we need only be concerned with the stronger radio sources. It is with this in mind that the default radio source catalog was created for this program. Over 290 sources were selected, most over 5 Janskys in strength. This catalog was compiled from several standard radio catalogs in order to cover the entire sky and include galactic plane objects. Over time, the catalog should improve as more sources are added. You can customize this catalog or create your own radio source catalog that more specifically addresses your needs. In addition you can import text catalogs into a format readable by the program, though this is not a trivial task. I hope to make more catalogs available in the Radio Eyes format and I encourage you to collaborate with other Radio Eyes users in developing source catalogs.
In addition to radio source catalogs which define discrete radio sources, there are image files that attempt to record the radio sky in terms of a 2D representation. These images or sky maps are the Backgrounds you see referred to in the Radio Eyes documentation. When a background file is loaded, Radio Eyes plots the catalog sources right on top of this map. Image information in the astronomical world is usually stored in FITS format. This format is a standard, but because it must have the ability to handle numerous dimensions it can be quite complex and cumbersome. In the name of speed and efficiency Radio Eyes uses a translation utility to produce a table of background "temperatures" from certain FITS image files. The actual picture you see is another component and is indeed saved as a standard gif or bmp image. Future versions of Radio Eyes should provide more flexible and easily used utilities for production of the necessary files for background viewing.
Related Topics:
VizieR On line catalog utility.
Editing Radio Source Catalogs in Radio Eyes Format
Converting Text Catalogs to Radio Eyes Format.
Creating Background Pictures and Temperature files from SkyView