Science and Technology Progress at the Sydney University Stellar Interferometer

TL;DR

This paper reviews recent advancements and modernization efforts at the Sydney University Stellar Interferometer, including new beam combiners and system upgrades, along with some scientific results.

Contribution

It reports on the development of new beam combiners and system upgrades, enhancing SUSI's capabilities and maintainability, along with initial scientific findings.

Findings

Development of the PAVO beam combiner continues.

The MUSCA high-precision astrometry instrument is under development.

System modernization improves reliability and performance.

Abstract

This paper presents an overview of recent progress at the Sydney University Stellar Interferometer (SUSI). Development of the third-generation PAVO beam combiner has continued. The MUSCA beam combiner for high-precision differential astrometry using visible light phase referencing is under active development and will be the subject of a separate paper. Because SUSI was one of the pioneering interferometric instruments, some of its original systems are old and have become difficult to maintain. We are undertaking a campaign of modernization of systems: (1) an upgrade of the Optical Path Length Compensator IR laser metrology counter electronics from a custom system which uses an obsolete single-board computer to a modern one based on an FPGA interfaced to a Linux computer - in addition to improving maintainability, this upgrade should allow smoother motion and higher carriage speeds; (2) the replacement of the aged single-board computer local controllers for the siderostats and the longitudinal dispersion compensator has been completed; (3) the large beam reducing telescope has been replaced with a pair of smaller units with separate accessible foci. Examples of scientific results are also included.