Share Email Print

Optical Engineering

Observational model for microarcsecond astrometry with the Space Interferometry Mission
Format Member Price Non-Member Price
PDF $20.00 $25.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

The Space Interferometry Mission (SIM) is a space-based long-baseline optical interferometer for precision astrometry. One of the primary objectives of the SIM instrument is to accurately determine the directions to a grid of stars, together with their proper motions and parallaxes, improving a priori knowledge by nearly three orders of magnitude. The basic astrometric observable of the instrument is the path-length delay, a measurement made by a combination of internal metrology measurements that determine the distance the starlight travels through the two arms of the interferometer and a measurement of the white light stellar fringe to find the point of equal path length. Because this operation requires a nonnegligible integration time to accurately measure the stellar fringe position, the interferometer baseline vector is not stationary over this time period, as its absolute length and orientation are time-varying. This conflicts with the consistency condition necessary for extracting the astrometric parameters, which requires a stationary baseline vector. We address how the time-varying baseline is "regularized" so that it can act as a single baseline vector for multiple stars, and thereby establishing the fundamental operation of the instrument.

Paper Details

Date Published: 1 July 2003
PDF: 11 pages
Opt. Eng. 42(7) doi: 10.1117/1.1576405
Published in: Optical Engineering Volume 42, Issue 7
Show Author Affiliations
Mark H. Milman, Jet Propulsion Lab. (United States)
Slava G. Turyshev, Jet Propulsion Lab. (United States)

© SPIE. Terms of Use
Back to Top