CROMWELL, as Project Scientist of the Vatican Advanced Technology Telescope (VATT), provided scientific, technical, and managerial guidance in the activities reported below. NELSON, as on-site assistant staff scientist, took the lead in many of the developments. Contributions came from many members of the Steward Observatory Technical Division, directed by DeRIGNE, especially from BRAR, WILSON, SCHALLER and HARVEY; from Vatican Observatory scientists BOYLE and CORBALLY; and from the Mt. Graham International Observatory (MGIO) staff, directed by RATJE. The VATT was scheduled on a regular basis during the past year for astronomical research. For long-exposure, direct images, image quality was typically better than 1.5 arcsec fwhm, and under the best conditions, 0.7 arcsec, using three different methods: unguided, manually guided, and--most recently--autoguided. Enhanced performance is expected when the thermal environment of the dome is improved, and autofocus and autocollimation are implemented. Major achievements this year include revamping of the secondary-mirror positioner; fine tuning of the primary-mirror side supports to promote stable optical alignment; and development of laser methods and imaging tests for critical mechanical and optical alignment.

BOYLE, as Telescope Scientist of the VATT, trained new observers in its operation. They included: RETTIG, RHIE, and KING (University of Notre Dame, Physics Department); UGLESICH (Columbia University, New York); BURG (Arizona State University); FUNES (University of Padua, Italy); and MCINTOSH (University of Arizona).

CORBALLY used the help of CLARK (London, England) to format the home page of the World Wide Web site of the Vatican Observatory (http://clavius.as.arizona.edu/vo) into HTML frames. A newly installed "hit" counter shows that the site has been visited, on average, 150 times per day since late August.

BOYLE and ROSSI installed three new Pentium PC computers at Castel Gandolfo. These are networked locally and are now running LINUX/IRAF version 2.11 or Windows NT. The Vatican Internet Office is increasing the speed of the microwave link to 128 kbps. The Observatory acquired an HP OfficeJet Pro 1150C color printer from the International Center of Relativistic Astrophysics, through the courtesy of RUFFINI (Institute of Physics, University of Rome).

Thanks to the generosity of a freelance gold prospector in Arizona, the Vatican meteorite collection now has several samples of the newly discovered Gold Basin meteorite. John BLENNERT and a colleague discovered a collection of meteorites scattered across the desert while searching for gold in northern Arizona. These meteorites may have been lying on the ground, relatively untouched, for hundreds of years. It is the first "fossil" field of meteorites found outside of Antarctica. Their samples were identified as meteorites by KRING (University of Arizona), who put BLENNERT in touch with the Vatican Observatory. In July BLENNERT donated four pieces to the Observatory.

During the past year negotiations were begun with EHLMANN, curator of the Monnig Meteorite Collection at Texas Christian University (TCU) in Fort Worth, Texas, to arrange for a trade of meteorites. As a result six samples from the Vatican collection (all of them meteorites for which there are multiple samples) were traded to TCU for six meteorites new to the Vatican collection. They are the ordinary chondrites known as Atoka, Julesburg, Kendleton, Leedey, Richardton, and Saratov, as well as a large, etched slice of the iron meteorite known as Glen Rose. The latter is now on display in the meteorite collection at Castel Gandolfo.

Meteorites from the Vatican collection were used by BONINO (University of Turin) for studies of magnetic remanence and solar-system magnetic fields, and by KITTS and FEGLEY (Washington University, St. Louis) for studies of trace elements in basaltic achondrites.

As part of an ongoing effort to make its collection more accessible to researchers worldwide, the Vatican Observatory has begun to prepare microscope thin sections of its more unusual and rare holdings. These sections will also make it possible for Vatican researchers to analyze these samples with the sophisticated (and very expensive) equipment found in other laboratories around the world.

These thin sections, which are 10-micrometer-thin slices of a sample mounted on a microscope slide, can be transported far more easily and more safely than larger samples. With them, researchers do optical microscopy as well as electron microscope and microprobe analysis of the mineralogical and chemical nature of the samples. Such analysis provides a detailed history of the rock. It also has the advantage of being essentially nondestructive.

The thin sections are being prepared in the laboratory of the British Museum of Natural History, London, with the assistance of GRADY, curator of meteorites there. Two slides are being made from each sample: one for the Vatican Observatory, and the other for the British Museum of Natural History in payment for their work. To date, fifteen meteorite samples have had thin sections prepared. These new slides have been added to the dozen very old ones already in the Vatican collection.

A new system for sorting and storing the Vatican meteorite collection was installed this past year. Each sample is now kept in an individual container, labeled according to the information in the new computer database (as described in previous annual reports). During this installation, a new inventory of the meteorites was done, so that the computer database has now been directly compared against the samples physically present. Work has also begun on the much larger task of entering complete descriptions of each sample into the database. With a collection of over one thousand samples, this is a long-term project. The eventual goal is to produce a new, more complete catalog of the collection, including an on-line version for the use of other researchers worldwide.