An accurate and sensitive instrument, capable of measuring small angular variations. This hand held NATO coded compass 6605-99-460-5338 is manufactured by SIRS and used in a wide range of applications. The compass is manufacture mostly from non-magnetic brass and liquid filled to provide card damping over a wide temperature range. A large high quality prism is used to magnify the card reading and accurate headings are taken through the prism sight line, a sight wire located above the compass card and the object being observed.
Typical uses include taking aircraft headings during a 'compass swing' procedure paticularly for small to medium sized aircraft. A special reverse-read version (1686REV ) is available to indicate the same headings as those read from the aircraft instruments during the compass swing operation, when viewing from the front of the aircraft. The compass is supplied with an impact resistant ABS stowage box and a calibration certificate. Subsequent calibrations can be performed by SIRS with a quick turn-round to ensure minimal loss of operation.
The Sirs Master Compass Radiant Model 1686 does come with a calibration certificate.