Public Open Houses

Free open houses are held on Friday evenings at 8:00 p.m. (9:00 p.m. during CU summer sessions) when CU classes are in session (during the spring, summer A & B, and fall semesters.)

SBO Public Event.

SBO public event on the observing deck.

Open houses are only held when the skies are clear. If you're not sure if we'll be open, check out our local weather with instructions for calling ahead. 

There is no charge for the Observatory's Open House nights ... the stars are free to everyone!

Sessions typically last from 1-3 hours, depending upon the weather, the quality of the night, and the enthusiasm and size of the crowd (if unsure of observing status call 303.492.2020). Please stop by anytime after we open and stay as long as you wish.

We also have tripod-mounted binoculars and the world's largest starwheel (well, at least we think it is) for identifying bright stars and constellations. Depending upon the staffing on a particular night, we may be able to offer you a chance to visit the 24-inch telescope ... that mysterious tube hiding hiding inside the dome ... as well additional smaller telescopes set up on the open deck for looking at the Moon and other bright celestial objects.

Most of our evening programs are hosted by the APS Department's graduate students, with an occasional faculty professor, researcher, local amateur astronomer, and/or undergraduate volunteer on hand.

Date of Observing Time of Observing Lunar Phase (% Illumination)

Aug 30, 2019

8:00 P.M.

0%  Illumination

New Moon

New Moon

Sept 6, 2019 8:00 P.M.  60% Illumination

Waxing Gibbous 60%

Waxing Gibbous

Sept 13, 2019 8:00 P.M.

99% Illumination


Full Moon

Sept 20, 2019 8:00 P.M.

67% Illumination

Waning Gibbous 70%

Waning Gibbous

Sept 27, 2019 8:00 P.M.

2% Illumination

Waning Crescent 0%

New Moon

Oct 4, 2019 8:00 P.M.

43% Illumination

Waxing Crescent  40%

First Quarter

Oct 11, 2019 8:00 P.M.

97% Illumination


Full Moon

Oct 18, 2019 8:00 P.M.

81% Illumination

Waning Gibbous 80%

Waning Gibbous

Nov 1, 2019 8:00 P.M.

27% Illumination

Waxing Crescent 30%

Waxing Crescent

Nov 8, 2019 8:00 P.M.

89% Illumination

Waxing Gibbous 90

Waxing Gibbous

Nov 15, 2019 8:00 P.M.

92% Illumination

Waning Gibbous 90%

Waning Gibbous

Nov 22, 2019 8:00 P.M.

20% Illumination

Waning Crescent 20%

Waning Crescent

Dec 6, 2019 8:00 P.M.

76% Illumination

Waxing Gibbous 80

Waxing Gibbous