The Harvard-Smithsonian Center for Astrophysics in Cambridge sponsors a variety of free programs for the public. Among these events are Observatory Nights on the third Thursday of the month, specially scheduled Kids Academy, Sci-Fi Movie Nights, and Star Parties.

These events—unless otherwise noted—are held in Phillips Auditorium (at the rear of the CfA complex near Madison Street and large parking lot), 60 Garden Street, Cambridge, about 1 mile west of Harvard Square. No reservations are necessary, but seating is limited to the auditorium's capacity.

Monthly Observatory Night Thursday, May 15, 7:30 pm: "Comets—Solar System Messengers," Daniel Green, CfA
Comets have awed mankind throughout recorded history, suddenly appearing as blazing apparitions in our skies. We now know that they are really dusty iceballs orbiting the Sun, but they still hold plenty of surprises. Just last fall, comet 17P/Holmes brightened unexpectedly by a factor of 400,000 in just two days, and in early 2007, the brightest comet in 41 years was visible to the unaided eye in broad daylight. Tonight, comet expert Dan Green will discuss what we know about comets and how we know it, including the frequency with which comets actually hit Earth and how comets are discovered and named. (The Spring schedule is available here.)
Watch it live

For more information, including accessibility, or to sign up for the events mailing list, call the Public Affairs Office, (617) 495-7461 or email pubaffairs@cfa. Please request sign-language interpretation at least 2 weeks before the event. Current sky information is available.

The CfA is easily reached by public transportation. From the Harvard MBTA Station (Red Line), take any bus or trackless trolley going west on Concord Avenue (Arlmont Village and Belmont Center buses, Huron Avenue trolleys) and get off at "Observatory Hill."