The John Payson Williston Observatory is the oldest academic building on campus. Originally built in 1881 and continuously upgraded over the years, it remains a state-of-the-art facility.
Its centerpiece is an eight-inch Alvan Clark equatorial refractor telescope from the original equipment set that is still in use. The observatory also houses a 24-inch Ritchey-Chretien reflector and seven 8-inch Meade LX-200 Schmidt-Cassegrain telescopes used by students.
The 24-inch telescope is equipped with a cooled CDD camera and spectrograph and a Sun workstation for analysis of digital images. The historic eight-inch telescope is also equipped with an electronic camera suitable for use by students in introductory astronomy courses.