Observatory status as of Saturday, April 20, 2024 @ 6:50 pm

IMPORTANT, please read this!

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.

The information in the table below is accurate as of the date and time shown at the top of this page. We try to update the current information before 7:00 pm on Fridays and Saturdays, but cannot always do so.

Clear skies!

The weather tonight is problematic with potential clouds or fog and high humidity (see above).

Leah – 8″ RefractoroperatingEarth’s Moon
Rachel – 20″ RefractoroperatingCastor (multiple star system) until sky gets dark ~9:00 pm, then either Iota Cancri (optical binary) or Algieba (binary star in Leo)
Nellie – 36″ ReflectoroperatingM3 (globular star cluster)