OIFITS 2: the 2nd version of the Data Exchange Standard for Optical (Visible/IR) Interferometry

TL;DR

This paper introduces OIFITS 2, an updated data exchange standard for optical interferometry that enhances data description, error modeling, and searchability, supporting current and future interferometric instruments.

Contribution

OIFITS 2 extends the previous standard with new data tables, improved error descriptions, and enhanced metadata, facilitating better data sharing and analysis in optical interferometry.

Findings

Supports multiple optical interferometer projects

Includes new data tables for polarization and errors

Expands metadata for improved data searchability

Abstract

This paper describes version 2 of the OI Exchange Format (OIFITS), the standard for exchanging calibrated data from optical (visible/infrared) interferometers. This IAU-endorsed standard has been in use for 10 years at most of the past and current optical interferometer projects, including COAST, NPOI, IOTA, CHARA, VLTI, PTI and the Keck interferometer. Software is available for reading, writing and merging OI Exchange Format files. This version 2 provides definitions of additional data tables (e.g. for polarisation measurements), addressing the needs of future interferometric instruments. Also included are data columns for a more rigorous description of measurement errors and their correlations. In that, this document is a step towards the design of a common data model for optical interferometry. Finally, the main OIFITS header is expanded with several new keywords summarising the content to allow data base searches.