Abstract

The Precision Optical INTerferometer in Space (POINTS) is an astrometric instrument comprising a metrology system and two starlight interferometers mounted at an angle ϕ ≈ 90 deg. This angle, which must be measured with an uncertainty small compared to the nominal instrument accuracy of 5 microarcseconds (μas), is determined by measuring the six distances among four fiducial points, two for each interferometer. The fiducial points are connected to the starlight optics via Full Aperture Metrology (Babcock et al., in this Digest; Reasenberg, in this Digest). Because of the observing geometry, the uncorrelated part of the error in the distance measurements must be held to a few picometers (pm). In this paper, we consider a new, “two color” laser gauge that appears to meet the requirements of POINTS. We are developing a test version of such a gauge.

© 1988 Optical Society of America