Flowdown of the TMT astrometry error budget(s) to the IRIS design

TL;DR

This paper discusses how the Thirty Meter Telescope's (TMT) detailed astrometry error budgets are translated into specific design requirements for the IRIS instrument, ensuring the system meets its astrometric accuracy goals.

Contribution

It presents a methodology for deriving subsystem design requirements from comprehensive astrometry error budgets for TMT's IRIS instrument.

Findings

Error budgets effectively guide subsystem design parameters.

The flowdown process ensures compliance with astrometric accuracy goals.

Methodology can be applied to other TMT instruments.

Abstract

TMT has defined the accuracy to be achieved for both absolute and differential astrometry in its top-level requirements documents. Because of the complexities of different types of astrometric observations, these requirements cannot be used to specify system design parameters directly. The TMT astrometry working group therefore developed detailed astrometry error budgets for a variety of science cases. These error budgets detail how astrometric errors propagate through the calibration, observing and data reduction processes. The budgets need to be condensed into sets of specific requirements that can be used by each subsystem team for design purposes. We show how this flowdown from error budgets to design requirements is achieved for the case of TMT's first-light Infrared Imaging Spectrometer (IRIS) instrument.