A status report on visibility measurement instrumentation within the U.S. Government

The development of visibility measurement equipment within various agencies of the U.S. Government is surveyed. The need to extend the 250-ft baseline of the AN/GMQ-10 transmissometer is stressed. The TASCAR 500 system, a dual-baseline transmissometer that uses a visible light transmitter and two detectors, is described, as is the EG&G forward scatter meter. There is also a description of the visioceilometer, a portable hand-held cloud height and visibility indicator. It is noted that slant visual range instrumentation development cannot proceed until user interest is regenerated and redefined.