MIT Reports to the President 1997-98


The George R. Wallace, Jr., Astrophysical Observatory is a teaching and research observatory located in Westford, Massachusetts. Its facilities consist of a 24-inch telescope, a 16-inch telescope, several 14- and 8-inch telescopes, a 5.5-inch astrograph, and a building that houses a workshop, darkroom, computer facility, and observers' quarters. Instruments used during the past year include a portable high-speed CCD occultation system, several small CCD systems, photographic cameras, and a high-resolution spectrograph.

Last year, course 8.287J-12.410J (Observational Techniques of Optical Astronomy) drew 8 students, who used the Wallace facilities for a variety of astronomical projects, including measurements of the periods both of a dwarf variable star and of an asteroid's lightcurve. For subject 12S23/12.409 (Observing the Stars and Planets, the first subject number distinguishes first-year vs. upperclass registrants), an additional 24 students used the Observatory for laboratory work. Informal field trips were offered for courses 12.401 (Beyond the Solar System; 6 students) and 12S22 (Hands-on Astronomy; 14 students), as was an observing session for freshmen last fall. An open house held during MIT's 1998 Independent Activities Period attracted over 30 people (mostly undergraduates, though faculty and staff from other departments came).

The 24-inch was used by Steve McDonald, Michael Person, and summer students to obtain astrometric CCD data for Pluto and Neptune's moon Triton, in addition to the star fields through which they will move during the next decade. These data will be used to identify and quantitatively assess stars that these bodies will occult so that observations can be carried out with telescopes that would happen to lie in the path where an occultation will be visible. The occultation data will be used to investigate how the thin nitrogen atmospheres of Pluto and Triton respond to changes in season and distance from the sun. Stars which were identified as probable occultation candidates were further observed to determine their apparent colors and magnitudes. In a related program, Mr. McDonald and the summer students produced refined predictions for the occultation of the star Tr180 by Triton. The 4 November 1997 event was successfully observed using the Hubble Space Telescope.

Mr. McDonald, Mr. Person, and students continued to develop a program to search for large, slowly moving objects that may be part of the Kuiper Belt population in the outer solar system. Dr. Steven Slivan continued a long-term project of imaging objects from the Messier Catalog.

Professor James Elliot and Dr. Heidi B. Hammel (with students Paul Collins, Adam Einarsen, Charles Borges, and Adam Gould) continued a collaboration with Professor Paul Schechter on the design of the MANIAC CCD camera for the Magellan telescopes in Chile, of which MIT has a 10% share of the observing time. Mr. Collins, along with contributions from Mr. Einarsen, drafted plans for a filter wheel mechanism. An evaluation of the expected dispersion caused by an instrument window was carried out by Mr. Borges. Mr. Gould created a top-down overview of information flow in the system. Current plans are to use Wallace Astrophysical Observatory as a local test-bed for MANIAC implementation.

Plans are continuing for a modern replacement to an older CCD system which was retired last year. Work is ongoing to improve the optics and drive system of the 24-inch telescope, and a prototype low-resolution spectrograph has been developed for the smaller telescopes.

Prof. Elliot continued his duties as Observatory Director. Dr. Hammel assisted with site management and telescope scheduling, with the help of Research Specialist Richard Meserole. Mr. Person has served as a part-time Technical Assistant for making observations, helping with observatory maintenance, and training students. Mr. McDonald continued his part-time work on software and computer management. Dr. Slivan assisted with supervision of summer student activities. Other staff (usually students) are coordinated through research programs. Undergraduates working on the spectrograph project (Lisa Kwok) and MANIAC instrument design (Paul Collins, Charles Borges, and Adam Gould) were funded in part by NSF's Research Experiences for Undergraduates (REU) program, as were the summer students (Shaida Bouramand, Adam Einarsen, Edgar Gonzalez, Lorraine Hertzog, Eric Nielsen, Rosa Villastrigo).

Heidi B. Hammel

MIT Reports to the President 1997-98