<title>Using scripting languages in optical interferometry</title>

Abstract

ABSTRACT Testbeds and production systems need lightweight, capable, and rapidly developed applications. We have developed several such scripts for testing and operating the Keck Interferometer. Two stand-alone (Tcl/Tk script) applications implemented to support the Keck Interferometer are discussed. The first is a front end to automatic and manual optical alignment embedded software, developed using the Keck Observatory Keyword API extension. The second is a user interface to the Interferometer Sequencer that communicates with it via both Keywords and Common Orbject Request Broker Architecture (CORBA). We discuss client-side CORBA scripts implemented in Tcl, Perl and Python. These are all technologies that are either currently being used on testbeds at JPL or being evaluated for future use. Finally, a Python example demonstrating implementation of a simple CORBA server is presented. Keywords: CORBA, Tcl, Python, Perl, Interferometer, Keck, Sequencer, Align 1. INTRODUCTION In the 990s scripting languages evolved rapidly to a very high level of sophistication. Extensible languages like Tcl, Perl and Python are ideal for rapid prototyping and rival the power of languages like FORTRAN, C, C++ and JAVA. At JPL we utilize these languages on several different projects. JPL's Real Time Interferometry Software Group is responsible for development of software and hardware technology to support implementation of astronomical interferometer systems. Both ground and space interferometer projects are currently in progress. The major ground based interferometer supported by the group links the two 0m telescopes of the W. M. Keck Observatory at Mauna Kea, Hawaii. In addition, several technology testbeds are being implemented for future flight missions including the Space Interferometry Mission (SIM). The Keck Observatory telescope control system was implemented using a software package called Experimental Physics and Industrial Control System (EPICS). EPICS is a distributed control system running at Keck on single board computers using the VxWorks real time operating system. EPICS software is also used to implement the alignment software of the Keck Interferometer optics. Client-side applications communicate with EPICS via a Keyword