Observatory doors open at 7:30 pm. Note that given how late the Sun sets, the sky doeasn't get dark enough for observing until about 8:45/9:00 pm. The public is welcome to look at the telescopes and see how they operate before it gets dark. There is information in the  Observatory classroom for the public to read and view prior to observing and to the start of the presentation. If entering the Observatory after 8:30 pm the public is requested to enter the building quietly as the presentation will be in progress.