Public Observing      

Next Scheduled:
Tuesday October 17th, 2023
8:00pm - 10:00pm
Status [last updated 1.3 wks ago (2023-09-20 02:01)]:
As of now, public observing is on for the coming night! Please check again closer to the date to confirm.

The department of Astrophysical Sciences at Princeton University holds monthly informal open houses for the purpose of observing the night sky. Weather permitting, we can usually look at planets, nebulae, open clusters, globular clusters, and galaxies through a 12” Schmidt-Cassegrain telescope. We (being the students and postdoctoral fellows in the department) are also quite happy to answer any astronomy-related questions you might have.

It is an open house, so come anytime during the above interval and stay as long as you like until closing. We will update the above calendar in the afternoon the day of scheduled public observing to indicate whether it is on or canceled due to weather, but there is no guarantee, of course, that the weather will not change between then and the start of the session, so please check the "Status" (above) on this website before you set off. For a last-minute check please look outside before leaving your house; if you can’t see any stars, neither can we!


WHERE: Peyton Hall, Ivy Lane, Princeton University. Unforuntately, because of ongoing construction, Ivy Lane is currently closed. Parking can be found in the Stadium Garage, Lot 10, the Prospect Ave garage, or street parking on Prospect Avenue (see map). To enter the building, walk between Lewis Library and Fine Hall. From the entrance, walk straight through the main hall and turn left, taking the stairs just before the end of the hallway. The telescope room is at the top of the stairs.

WHEN: Open houses this year will *usually* be on the second or third Wednesday of each month, with an alternate date the next Wednesday in case of cloudy skies or poor weather. Sometimes these days/times will be moved because of competing campus events, so watch this website. We may also hold special events. The status of the upcoming observing session is shown above, and the full schedule for the semester is posted below.

For more information, contact Camryn Phillips At

Note: We usually decide whether the weather will be good enough to hold our observing session by about 3:00 PM on the day in question. Please check this site after that time to make sure that we’re going ahead, and please check it again immediately before you come! Sometimes we make mistakes, and we cancel when the weather is clear, or are forced to cancel at the last moment because of unexpectedly bad weather. Apologies in advance for all such mistakes. If you’re really interested, check the Clear Sky Chart tab (the same astronomy weather info we use to make such determinations).

Summer 2023 Schedule

Date Start time  Type of session
Sep 19, 2023 (Tue)8:00Main
Sep 21, 2023 (Thu)8:00Back-up
Oct 17, 2023 (Tue)8:00Main
Oct 19, 2023 (Thu)8:00Back-up
Nov 21, 2023 (Tue)7:00Main
Nov 28, 2023 (Tue)7:00Back-up
Dec 12, 2023 (Tue)7:00Main
Dec 24, 2023 (Thu)7:00Back-up

Map to Peyton

Peyton Hall is circled in red, with the entrance marked by an arrow. Parking is available either in the circled lots and garages, or limited street parking may be available on Prospect Avenue. Parking in most university lots is open to the public after 6pm.