The Vigilant Aircraft Hygrometer is a rugged, shock mounted instrument used for accurate measurement of dew/frost point in flight or in installations with existing flow, such as wind tunnels.

The Vigilant features a miniature, remote or mounted, primary method chilled mirror dew/frost point sensor employing a platinum resistance thermometer and has 15 feet of interconnecting cable to the control unit when used remotely. Longer cable lengths are optional. Precision calibration units for the linear analog outputs are included.

A specially designed dew/frost point sensor can be mounted through the skin of an aircraft on either the left or right side. The dew/frost point detection method utilized assures precision accuracy, high repeatability and high reliability.