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Public Telescope Nights

The public is invited to join the Dexter Southfield community for an evening of viewing at the Clay Center Observatory. The Observatory will open on Tuesday evenings, weather permitting.

Depending on conditions and season, we will point the telescope toward a variety of planets, the Moon, and stars. Visitors also can enjoy a panoramic view of greater Boston from the observation decks, and walk among the constellations on the stars court. Children are welcome, but must remain with parents at all times. 

Please register in advance for this event. This will help us to make the experience as enjoyable as possible for everyone. If the weather is rainy or overcast, we will not open. If you have any questions about the telescope nights, the weather, bringing groups, or future telescope nights, call 617-751-3409 one hour before the event.

Will we still see anything if the sky is partly cloudy?

Yes, we can work around larger clouds by pointing the telescope at objects in a clearer part of the sky. The telescope will often be able to "see through" thin, wispy clouds. If the weather looks doubtful, please call 617-751-3409 an hour before the event to confirm whether it is on or postponed.

Do you notify us if the weather turns and you have to close?

Sometimes. If we know ½ a day in advance that we will close, we will try to send out a notice to those who have registered. However, since New England weather can go from really bad to really good in a matter of an hour or so, we usually don’t make the call until about an hour before the opening time. Therefore, we ask that people look at the sky and use their judgment. If overcast, don’t bother coming; if in doubt, call the recorded line for the latest update. We find this works best because we have, on occasion, called off too far in advance only to have the skies clear suddenly and make us and the forecasters feel like fools.

If bad weather improves, how will we know if you will now open?

If the clouds disperse and stars come out, we will likely open. If it was raining and then stopped, probably not. We cannot open when the dome is wet or there is high humidity (saturated air). If you want to check, call the observatory recorded line about 1 hour before the event. If you call during the event hours, the astronomer may answer, if he/she is not too busy, and give you the latest update.

What else can we do while visiting the observatory?

We often open the roof deck and put out smaller telescopes that you may control, and an astronomer can point out constellations and other naked eye objects. Inside we usually post an astronomer with handouts to answer questions about buying telescopes, starting astronomy with kids, how to observe, etc. Most nights the fiber-optic lit Stars Court is open.

How will you handle a large group in the Observatory?

The 25-foot diameter dome has enough space for at least 20 adults at a time. If we have more people than that, we may break into groups and circulate through the observatory and back to the 5th floor multi-purpose room. The observatory has two staircases and air-locks to facilitate traffic flow.

Is the observatory wheelchair accessible?

Yes. Very few observatories are, but we made it a priority in our design of the facility. After taking the elevator to the 5th level of the Clay Center, there is an HP lift that goes to the observatory air-lock level, and another that goes from there up to the floor of the observatory. We have a special articulated eye piece extension that will allow viewing even if a member of your party is unable to stand to reach the telescope. Please notify us in advance so that we can prepare.

What is the temperature inside the observatory?

It will be as hot or cold inside the dome as it is outside. We suggest that you wear a warm jacket on cool nights. The rest of the 5th floor facility is heated, so you may go there to warm up.

Why do you start the event so late?

We schedule them for the earliest time that the sky is dark enough to enjoy viewing with telescopes. We schedule according to sunset and Daylight Savings time shift.

Why don’t you open year-round?

We are unable to open during the winter when there is snow on the roof, or when it is too cold for people in the dome. Other breaks in the public schedule are due to breaks in our school schedule when staff, or the building, are not available.

Where can I find directions for the Clay Center on campus?

Directions to the Clay Center can be found here. 


Dexter Southfield School • 617-522-5544 •

Report an Absence • Admissions: 617-751-3600

20 Newton Street Brookline, Massachusetts 02445 Directions


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