Entry No. 67 — the Boulder file — filed under: after-dark
Sommers-Bausch Observatory Friday Open Houses
On clear Friday nights during the CU school year, this campus observatory opens its rooftop observing deck and points its 20-inch telescopes at the moon, planets, nebulae, and galaxies. It is completely free, and cameras on the scopes throw the live views up onto big screens on the deck so you can compare what your eye sees with what the sensor catches. Sessions run loose and long, anywhere from one to three hours depending on the sky and the crowd's enthusiasm.
The story
Funded by a 1949 bequest from Mayme Sommers in memory of her husband Elmer, the Sommers-Bausch Observatory opened in 1953 in the university's signature rural Italian style. Operated by CU Boulder's Department of Astrophysical and Planetary Sciences, its primary job during the week is teaching undergrads how to collect light from distant stars. But on clear Friday nights when school is in session, the department opens the doors to anyone who wants to walk up to the rooftop observing deck.
You aren't peering through back-garden consumer gear here. The rooftop deck features twin 20-inch PlaneWave CDK telescopes—nicknamed Apollo and Artemis—mounted on heavy-duty motorized tracking piers, alongside a 24-inch Boller & Chivens reflector inside the main dome. Digital sensors attached to the scopes stream live, high-sensitivity images onto big monitors on deck, letting you compare the faint optical image your eye catches through the glass against the rich colors captured by the sensor.
The open houses skip the academic stiffness. Run by graduate students and astronomy faculty, the sessions run loose and long for one to three hours. They take target requests, explain celestial mechanics in plain terms, and swing the heavy optics toward whatever planet, nebula, or star cluster is cutting cleanest through the atmosphere.
What it's like
Before heading up to the rooftop at 2429 Kittredge Loop Drive, call 303-492-2020 after 7:45 PM to make sure Front Range clouds haven't scrubbed the night. Once you arrive at 8 PM (9 PM in summer), expect a loose, friendly crowd of students and locals lining up for eyepiece turns. Open rooftops in Boulder cool off quickly after dark, so bring a jacket even on mild evenings. The lines move fast, and the student hosts are glad to hunt down specific objects if you ask.
The move: Check the clear-sky status after 7:45pm, then head up to the observing deck and take turns peering through the 20-inch telescope at Saturn's rings or a distant nebula.
📍 Before you go Open houses are Friday at 8pm (9pm in summer), only when CU is in session and skies are clear; call 303-492-2020 after 7:45pm or check their socials for go/no-go.
- 📍 University Hill, Boulder
- 💸 $
- ⚡ Low-key
- 🌗 Outdoors
Where: 2429 Kittredge Loop Dr, Boulder, CO 80309
Hours: Added 2026-06-23 — confirm current hours before you go.
⚠ Seasonal or scheduled — always check before you go.
Pair it with
- Fiske Planetarium Late-Night Laser Shows — Located right on campus, Fiske lets you combine real stargazing on the observing deck with an 8K dome laser or music show.
- The Sink — Head 0.8 miles west onto University Hill after stargazing for local beer and pizza inside a legendary 1923 basement bar.
- Columbia Cemetery — Pair a night gazing light-years into deep space with an afternoon walk through Boulder's historic 1870 burial ground just over a mile away.
Good to know
How much does it cost to attend a Friday Open House?
It is completely free, with no tickets or advance reservations required.
How do I know if the open house is happening tonight?
Open houses require clear skies and take place only when CU Boulder is in session. Call 303-492-2020 after 7:45 PM on Friday to hear the go/no-go status recording.
What time do the sessions start?
Sessions start at 8:00 PM during the fall and spring school terms, shifting to 9:00 PM during summer sessions.
What telescopes will I get to look through?
Visitors use the rooftop deck's twin 20-inch PlaneWave telescopes, which are also linked to live display monitors. Depending on staffing and scheduling, the dome housing the 24-inch Boller & Chivens telescope may also be open.
Plan a visit & invite your people →
Further reading: colorado.edu · Wikipedia
last checked: 2026-06-23