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Hubble Space Telescope
HST Overview

In 2005, the Hubble Space Telescope (HST) celebrated its 15th anniversary of on-orbit operations. Throughout this period, each new generation of instruments has opened up a quantum leap in discovery potential. Most recent is the Advanced Camera for Surveys (ACS), installed in 2002, which has played a prominent role in HST science. In addition, the NICMOS Cooling System (NCS) returned the telescope to the forefront of near-infrared astronomy. The next generation of instruments, the Wide Field Camera 3 (WFC3) and the Cosmic Origins Spectrograph (COS), are likewise expected to yield rich discoveries.

Moreover, some steps have been taken to extend the life of HST, thereby also extending its scientific potential. Most notable was the transition to Two-Gyro Mode (TGM) in August 2005, activating a new attitude control system that requires only two gyroscopes and allows other gyroscopes to be turned off, to conserve their lifespan for future use.

With new instruments and modes of operation, new calibration challenges also arise, since forefront science demands pushing the telescope and its instruments to their limits. Each new instrument requires extensive calibration before launch and during on-orbit operations. Instruments that have been in operation for a long time permit detailed studies of changes in long-term behavior. We also learn about instrument failure modes and possible ways to repair them, such as the STIS failure. Finally, when instruments are decommissioned, extensive “close-out” calibrations provide a long-lasting scientific legacy.

The 2005 HST Calibration Workshop was held at the Space Telescope Science Institute during October 26−28, 2005 to bring together members of the observing community, the instrument development teams, and the STScI instrument support teams to share information and techniques. Presentations included the two-gyro performance of HST and FGS, advances in the calibration of ACS, NICMOS, STIS, and WFPC2, results on FOS and GHRS after their return from space, and the status of WFC3 and COS which are scheduled for installation during the next servicing mission. Cross-calibration between HST and JWST was discussed, as well as the new Guide Star Catalog and advances in data analysis software. A total of 105 astronomers attended the workshop which featured 41 talks and 35 posters, as well as splinter groups, demonstrations, and discussions on various topics.

This book contains the published record of the workshop, while all the talks and posters are available electronically on the workshop website. As our knowledge of the instruments continues to improve, the latest information is always available from the STScI website.

We wish to thank all the participants and organizers for making this workshop a success. The workshop was sponsored by the Instruments Division at STScI, and we thank all the members of the Organizing Committee, as well as Dixie Shipley, Susan Rose, Harry Payne, Calvin Tullos, Mike Wiggs, Helmut Jenkner, Margie Cook, and Robin Auer for all their logistical and administrative support in running the workshop and making these proceedings possible. We also thank NASA Headquarters, the HST Project at the Goddard Space Flight Center, and the Space Shuttle Program support staff at the Johnson Space Flight Center and Kennedy Space Center for their outstanding support of all HST servicing activities.

We would like to dedicate these proceedings to all the astronauts whose heroic commitment to the Hubble mission makes it possible for humankind to continue exploring the universe in this unique way. We all owe a tremendous debt to these brave individuals. The Editors

Anton M. Koekemoer, Paul Goudfrooij, and Linda L. Dressel

January 2006