The Clay Center Observatory, on the campus of Dexter Southfield School (20 Newton Street in Brookline; 5th floor), holds Public Telescope Nights on most Tuesdays in the spring and fall, from 8PM to 9PM.  They’ll be open from through June 6. Register in advance.  Events are canceled if weather is rainy or overcast:  Call 617-454-2795 one hour before the event for a recorded message.  The Clay Center offers a range of Outreach Programs for community groups.  Check the Center’s calendar for future events.