Welcome to the Blackbird Archive: One of the best resources on
the Internet for information, photos, and diagrams pertaining to
the A-12, YF-12, SR-71, and D-21. This archive contains history and
specifications on all Blackbird variants and most other associated
aspects.
In describing the tracking motion of an AZ-EL or ALT-AZ mounted
radio telescope, to "plunge" means to exceed 90° in elevation
and then to continue tracking as elevation decreases on the other
side without swiveling around in azimuth. This is not a capability
of DSN antennas.
Read More
