Calibration Software

Introduction

Calibration software is used to acquire, catalog, and analyze preflight instrument test data in order to facilitate meeting the primary goals of the IDL calibration team.

Software is used to acquire raw data, usually SHP (Standard Header Packet) and SDI (Science Data Image) files that come directly from the instrument. The telemetry data are interpreted and converted into keyword/value pairs to be written, along with the image data, to a FITS format file.

We catalog a preselected subset of the available telemetry items in an IDL database. In many cases these items correspond to the Space Telescope Science Header definition. But since our database and headers predate the ST definition not all keywords and values correspond exactly. A copy of our catalog is searchable online.

The software for acquisition and cataloging was originally based on similar software developed for the STIS HST program. However the ACS calibration team has made great improvements in code stability and process automation to the extent that by mid 1999 the software was completely automated. This includes seamless integration with the legacy ACSVU engineering (GSE) archive.

We analyze the data in order to provide feedback to the engineering groups involved in the design of the instrument, and information that will be used to verify the performance of the instrument.

Like the acquisition and cataloging software, some analysis routines have been developed which can proceed without user intervention. For example the DINO (Detector Induced NOise analysis) program was run for many weeks during our ACS/NCS compatibility tests during the summer and fall of 2000.

The ability to process our data automaticly has allowed us to operate more speedily and consistently while conserving our personnel resources.

Resources

For each of these cases much of the software is written in the IDL language, of which we have developed a library of routines.