There are two kinds of catalogs included in W3Browse, catalogs of observations by various instruments, and catalogs of objects. To access the archive a user will typically search an observation catalog and then request the data associated with the observations selected. Object catalogs are more typically searched to find matching objects, to classify sources, or similar tasks. A few object catalogs are associated with archival data. New catalogs are constantly being added.
Users can search tables in several different ways.
Users may simply request an image by specifying a position, or can make very detailed request for the size, scale, orientation, projection and coordinate system for the data. Most surveys cover the entire sky. Basically any resource that is queryably by position is eligible for entry into Astrobrowse. Currently over 1,000 resources are available. Many of the utilities described above are extremely useful in preparing proposals.