MIT Reports to the President 1999–2000
The George R. Wallace, Jr., Astrophysical Observatory (WAO) is a teaching and research observatory located in Westford, Massachusetts. Professor James Elliot ’65 is the Director, Dr. David Osip ’89 serves as the Assistant Director/Manager, and Mr. Richard Meserole is the Observatory Technical Specialist. Other staff (usually students) are coordinated through research programs. Undergraduates working on the various projects are funded in part by NSF’s Research Experiences for Undergraduates (REU) program and in part by NASA and NSF research grants to Prof. Elliot and Dr. Osip. Observing facilities consist of a 24-inch reflecting telescope and a 16-inch reflecting telescope, a 4 bay shed with roll-off roof housing three Celestron 14-inch Cassegrain telescopes as well as a 5.5-inch astrograph, and several Celestron 8-inch Cassegrain portable telescopes. Additional infrastructure includes a building housing electronics workshop, data analysis computer facilities, and observers’ quarters. The primary instrument for the 24-inch telescope has been a portable high-speed CCD camera system [PCCD] mated to a custom optics box providing 5:1 field compression at the Cassegrain focus. All other telescopes are equipped with CCD (charge-coupled device) camera systems and dedicated control computers. Additional instruments used during the past year include several photographic cameras, and a high-resolution spectrograph.
A major facility upgrade is currently underway at WAO. Dr. Osip and Richard Meserole are modifying and implementing a new telescope control system known as MOVE (designed originally at Lowell Observatory). As part of this process, the entire telescope has been disassembled for the first time since it was built 30 years ago. All components are being thoroughly cleaned, stripped and painted. The only operating parts of the existing telescope drive that are being kept are the main worm gears for the Right Ascension and Declination axes. These gears have been cleaned, inspected and re-packed with grease. New close-looped encoded stepper-servo motors are being mated to custom 10:1 reduction gearing for both axes. This new drive system will allow full computer control of all telescope motions tracking at both sidereal and non-sidereal (for solar system objects) rates with positional accuracy of better than 0.1 arcseconds. While the telescope is being worked on, the primary and secondary mirror will be tested, polished and re-coated; they will be re-installed in the newly completed telescope by the end of the summer. This year, PCCD has been integrated with the 16-inch telescope during this major upgrade of the 24-inch facilities.
Last year, course 8.287J-12.410J (Observational Techniques of Optical Astronomy) drew eight students, who used the Wallace facilities for a variety of astronomical projects, including broadband imaging of star clusters to construct color-magnitude diagrams and moderate temporal resolution photometric imaging of asteroid light curves to deduce rotational characteristics. For subject 12S23/12.409 (Observing the Stars and Planets, the first subject number distinguishes first-year from upper-class registrants), an additional 23 students used the Observatory for laboratory work. Our planned IAP tour was unfortunately cancelled due to weather, however, more than two dozen students were able to take part in a night of observations that we hosted with MIT Students for the Exploration and Development of Space (SEDS).
Professor Elliot and Steve McDonald ’84 have completed a project of high astrometric quality image scans of the star fields through which Pluto and Neptune’s moon Triton will cross over the next decade, using PCCD at the 24-inch. The astrometric data have been used to identify stars that will be occulted by these two bodies and quantitatively assess where the occultation path will be visible on the Earth so that necessary observing campaigns can be planned. The eventual 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. This has been a long-term project carried out by several summer UROP and REU students with supervision provided by graduate student, Michael Person ’94 as well as Professor Elliot, Steve McDonald, and Dr. Osip. Results of these occultation candidate searches for both Pluto and Triton have recently been published in the Astronomical Journal.
Dr. Osip and UROP student Aletta Wallace ’03 along with colleagues at Lowell Observatory are developing a modular telescope and instrument control system to be used by MIT’s MAGIC CCD camera for the Magellan telescopes in Chile, of which MIT has a 10% share of the observing time. Current plans are to use Wallace Astrophysical Observatory as a local test-bed for MAGIC implementation prior to bringing the camera to Chile.
More information can be found at the URL http://web.mit.edu/wallace/.
David J. Osip
MIT Reports to the President 1999–2000