IMPORTANT, please read the text below!

The telescopes are operated in the evenings year-round on Friday and Saturday from 7:30 to 10:30 pm. Generally, the observatories are open and volunteers are available to show the telescopes and explain their history and operation even when weather conditions prohibit viewing through the telescopes. The observatories are closed, however, if it is raining or the area outside the observatories is wet.

The telescopes cannot see through thick clouds. Also, to avoid condensation on the telescopes, they are not operated when the humidity is above our limits. Nellie is not operated when the humidity is above 84% and the two refractors do not operate when the humidity exceeds 89%. The current humidity at the observatories is highlighted in bold yellow, below. The normal pattern for humidity at Chabot is for it to reach a minimum in the afternoon and increase over the rest of the day. If you are looking at this in the early evening and the humidity is in the 70’s or low 80’s it is suggested that you wait twenty to thirty minutes and recheck the humidity before deciding whether or not to make the trip.

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The information here and in the table below is current as of Saturday, June 14, 2025 @ 7:20 pm.

There will be no telescope operation today. PG&E is servicing local power lines, and all electrical power at Chabot Space & Science Center has been turned off until 4:00 a.m. on the 15th. Please check back with us on Friday, June 20, when the observatories will again be open for public telescope viewing

TelescopeStatusViewing
Leah – 8″ RefractorNot operating tonight.
Rachel – 20″ RefractorNot operating tonight.
Nellie – 36″ ReflectorNot operating tonight