The commissioning phase

TL;DR

This paper describes the commissioning process of a telescope from initial readiness through testing, tuning, and first-light observations, culminating in routine scientific use with all instruments installed.

Contribution

It provides a detailed account of the commissioning phases, integration, testing, and operational milestones of a large telescope system.

Findings

Telescope achieved first-light in June 1998.

80% of time dedicated to astronomy after commissioning.

All first-light instrumentation successfully mounted by April 1999.

Abstract

In May 1997 a consistent part of the services and structures committed to the industry had already been released to the commissioning group. The telescope itself was, with the exception of the Nasmyth derotators, motors and all the optics groups, basically ready in its mechanical parts to accept the integration of all services and control equipment. Also the verification of the cabling (interlocks, data-nets, power and controls) already mounted was started in the same period. Starting from June 1998 (telescope first-light date) the telescope went gradually in use, several nights per week, in order to test and tune the tracking and pointing system, the optics and the first derotator system (Nasmyth A station). At the end of the commissioning period and with the first scientific instruments mounted (April 1999) also the first routinely observations started. In this moment the telescope is doing astronomy 80% of time and the complete first-light instrumentation is mounted.