Postage-stamp servers are services which allow the user to retrieve images of small areas of the sky, in a standard format. The first such astronomical server to be made available on the World-Wide Web is the ISSA-PS, providing data from the Infrared Sky Survey Atlas, an all-sky survey made by IRAS (Infrared Astronomical Satellite) at wavelengths of 12, 25, 60 and 100 microns.
All but a few percent of the sky are covered with 1.5 arcminute pixels. These data are also available on CD-ROM from the National Space Science Data Center at NASA's Goddard Space Flight Center.
Postage stamps cover a 2-degree field centered on a given target. Targets may be specified either by 1950 equatorial coordinates or by name. Names are converted to positions using the SIMBAD database in Strasbourg, France.