George R. Wallace, Jr., Astrophysical Observatory
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 has served as the Observatory Technical Specialist (Mr. Meserole left the observatory this spring and the search for a replacement is currently nearing completion). 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 four-bay shed with roll-off roof housing three Celestron 14-inch Cassegrain telescopes (C-14) 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 moderate-resolution fiberoptic spectrograph.
A major facility upgrade is currently nearing completion at WAO. As part of this process, the entire 24-inch telescope was disassembled for the first time since it was built 30 years ago. A new drive system has been constructed with close-looped encoded stepper-servo motors mated to custom 10:1 reduction gearing for both axes. These drives are currently undergoing lab testing by graduate student Janet Wu '00 and are to be installed in the newly assembled telescope in August. A new telescope control system known as MOVE (designed originally at Lowell Observatory) is also being implemented. 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. The primary and secondary mirror have been tested, re-figured, polished and re-coated; they will be re-installed in the newly completed telescope by the end of the summer. The resulting optical configuration is a substantial improvement over the previous system and should provide sub-arceseond performance.
This year, PCCD has been undergoing its own system upgrades in preparation for upcoming occultation observing campaigns (the original purpose for the portable system). Graduate student Michael Person '94 and undergraduate James Pate '03 have been carrying out the PCCD work under the supervision of Professor Elliot. A new Apogee CCD camera incorporating a high quantum efficiency, back illuminated SITe detector in a 1024x1024 (24 micron) pixel array has been purchased to serve as the prime camera for the updated 24-inch telescope. This camera is currently undergoing initial testing and performance evaluation on one of the C-14 telescopes in the shed. It will be mated to the 24-inch with a filter slider and under computer control later this summer. Development is now beginning on an implementation of the Lowell Observatory Instrument System (LOIS) for remote camera control. LOIS is a modular telescope and instrument control system developed as a collaboration between Lowell Observatory and the Planetary Astronomy Laboratory (http://occult.mit.edu/pal/) at MIT. It is currently in use for the MagIC camera (http://occult.mit.edu/magic/) at the Magellan I telescope in Chile (http://www.lco.cl/magellan_lco/). The WAO camera project is being primarily carried out as a Masters thesis project by graduate student Janet Wu under the supervision of Dr. Osip
Last year, course 8.287J/12.410J Observational Techniques of Optical Astronomy drew 11 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. In addition, a new fiberoptic spectrograph system was used for the first time to allow students to do moderate resolution single target spectroscopy observations. This system will be enhanced to offer lower and higher resolution gratings and a second system will be available for the upcoming academic year. For subject 12.409 Observing the Stars and Planets, an additional 27 students used the observatory for laboratory work. In addition, several small group observing sessions have been offered for interested students to use the facilities as an extracurricular activity.
More information can be found online at http://web.mit.edu/wallace/.