Sawyer 24-in Reflector

Sawyer 24-in ReflectorThe 24-in reflector at Whitin Observatory, built by Boller and Chivens in 1966, was a gift from Mrs. Margaret Sawyer. Its f/13.5 Ritchey-Chrétien Cassegrain optics are presently used with an additional focal length reduction lens yielding an effective focal ratio of f/9.6.

The primary imaging instrument currently on the telescope is an Apogee Instruments 2k x 2k CCD camera which has been in use since summer 2011. The GAM filter wheel in front of the camera holds six 50-mm square filters, selected from among a set of broadband photometric UBVRIgriz and colorless filters from Omega Optical, plus 890-nm methane absorption and hydrogen-alpha band filters.

The 24-in telescope and its instrumentation has been used since it was installed in 1966 to teach observational astronomy techniques to intermediate and advanced students. It's also heavily used to carry out research programs at the Whitin Observatory.  Current research programs include exoplanet transit observations for the Kilodegree Extremely Little Telescope project and an ongoing study of the spin properties of Koronis family asteroids. Past projects include long-term observations of symbiotic binary star systems, variable star studies, and supernova monitoring.

In 1991, the original telescope drives and relay control system were replaced with a computerized retrofit motion control system by DFM Engineering. Several subsequent improvements were made to the telescope during the summer of 1995, including a DFM upgrade to the control system, installation of a DFM “Guide-Acquire Module” (GAM), and changes to the dome and structure to improve the seeing. In 2003 December the control system was upgraded to a Windows-based version of the DFM software.

The original instrumentation accompanying the telescope was a Boller and Chivens 4 × 5-in photographic plate camera. Other instruments that have been used on the telescope in the past include a photoelectric photometer (ca. 1969), an Optomechanics Research Model 10C Grating Spectrograph (ca. 1982), a Photometrics 512×512 “PM512” CCD camera for electronic imaging (1990), and a successor Photometrics/SITe 1024×1024, 16-bit, back-illuminated, Metachrome-coated “TK1K” CCD camera (1995-2011).

Contact Us

Contact Us

Wellesley College Astronomy Department
Whitin Observatory 
Wellesley College
106 Central Street
Wellesley, MA 02481

Tel: 781.283.2726 
Fax (in Science Center Office): 781.283.3642

 

Drop-in tutoring hours for students in ASTR 100/101 will be 3:00-5:00 PM on Tuesdays in the Observatory Library

There will be no more non-lab observing until at least Monday Sept. 15.