and other applications. The Haystack technique uses a 36 channel, high accuracy narrow-track headstack that can be moved precisely across tape to increase the density of the recorded information by a factor of more than 12, so that a single reel accommodates nearly 6 terabits and can record at a rate in excess of 1 Gbit/sec. Honeywell of Denver is now producing these high-density headstacks as a standard component.

Radio astronomers have been both drivers and developers of low noise amplifiers, including cryogenically-cooled gallium-arsenide field effect transistors (now marketed by Berkshire Technologies, also founded by radio astronomers) and high electron mobility transistors, which may replace masers in some communications amplifiers.

The computer control language FORTH was invented by a professional programmer with a strong interest in astronomy and first applied by him to coordinate telescope operation, data acquisition, and initial reduction for the NRAO 36-foot dish at Kitt Peak. It has grown into a profitable company (Forth, Inc., Manhattan Beach, California) and been modified for a wide range of purposes in manufacturing and service industries. About 20 vendors supply Forth systems for hardware from handheld computers to VAX mainframes. Some computers (most recently the Harris RTX 2000 microprocessor) execute Forth directly. The system is currently used in a rule based ("expert system") automobile engine analyzer at over 20,000 service stations world wide and in a high-accuracy densitometer used by Kodak for quality control in film manufacture. The initial support from NRAO and wide diffusion of Forth through the astronomical community were instrumental in its development into a broadly-applicable system.

Other examples of fruitful technology transfer from astronomy include:

• Use of AIPS (a set of image processing programs from radio astronomy) by Boeing to test computer hardware (several vendors, including Convex and International Imaging Systems advertise that their systems support AIPS).

• General Motors' application of IDL to analyzing data on car crashes.

• Acquisition of the patents for the first gravitational radiation detectors by Hughes Research Laboratory for use in modified form to sense gravity anomalies associated with underground oil pools.

• Use of the IRAF image processing program at AT&T for solid state physics graphics and computer systems analysis.

• Cold spot welding techniques that do not distort the underlying metal, developed at University of Wisconsin during construction of OAO-1.

The common technological needs of astronomical observations and of certain defense programs have often resulted in one research community developing techniques or making observations useful to the other. For example, satellite and aerial surveillance have replaced many ground-based intelligence activities. The resulting increased certainty (on both sides) that accurate information will be available has contributed to recent progress in arms reduction. Surveillance requires telescopes with large accurate mirrors, precision optics, and the ability to process numerous imperfect images and extract the maximum possible amount of information. The necessary large mirror technology, adaptive optics, and processing algorithms have all had significant input from techniques developed within astronomy and by people trained as astronomers, from the time of the U2 cameras to the present. Some specific examples which extend across the electromagnetic spectrum:

• A recent investigation at Grumman on recognizing rocket plumes for strategic warning purposes made use both of observations of stars and of model stellar atmospheres to discriminate plumes from cosmic objects.

• Aperture synthesis radar is the remote descendent of the radio astronomy technique for which Martin Ryle won the Nobel Prize.

• Development of the channeltron was supported originally for ultraviolet astronomy, but it has since found its way into various uv military cameras.

• Expertise developed in conjunction with the Kuiper Airborne Observatory has provided direct support to several Navy and Air Force airborne infrared sensor development programs.

• Star counts and models of stellar spatial distribution are used to assess data rates for spaceborne signal processors and sensors as well as for satellite pointing and calibration.

Front Matter (R1-R12)

Radio Astronomy (1-24)

Infrared Astronomy (25-46)

Optical/IR from Ground (47-74)

UV-Optical from Space (75-106)

Interferometry (107-128)

High Energy from Space (129-152)

Particle Astrophysics (153-176)

Theory and Laboratory Astrophysics (177-198)

Solar Astronomy (199-234)

Planetary Astronomy (235-256)

Computing and Data Processing (257-282)

Policy Opportunities (283-300)

Benefits to the Nation from Astronomy and Astrophysics (301-320)

Status of the Profession (321-340)

Science Opportunities (341-342)