Entry No. 147 — the Denver file — filed under: observatory
Little Thompson Observatory
The Little Thompson Observatory is a fully volunteer-run public observatory on the Berthoud High School campus, housing a 24-inch Mount Wilson telescope that was used to map the lunar surface for Apollo mission landing site selection — you can peer through the same optics that helped put humans on the moon. Free public star nights run on the third Friday of each month, drawing hundreds of visitors with trained volunteer astronomers on hand.
The story
Drive past the main parking lot of Berthoud High School and you will miss it entirely. Tucked behind the athletic fields sits an unassuming blue building crowned with two white domes. You didn't hear it from us, but this small-town high school campus holds genuine Apollo-era aerospace history: a 24-inch Mount Wilson telescope that was used to map the lunar surface so NASA could choose landing sites for the Apollo missions.
The observatory didn't start with federal funding or a university endowment. In the mid-1990s, local science teachers and community members formed a grassroots effort to build an astronomical facility from scratch. Over 10,000 volunteer hours went into constructing the original building, with physical labor and materials pitched in by local contractors and Habitat for Humanity, while the Thompson School District provided the land, utilities, and insurance.
The Apollo telescope arrived years later through pure persistence. In 2007, two observatory volunteers drove a truck to California in 114-degree heat to pick up the massive instrument on long-term loan. Today, instead of sitting behind glass in a museum or locked inside a defense facility, the optics that helped humans step onto the moon are operated by volunteer astronomers who let you look through the eyepiece for free.
What it's like
Arrive for the monthly Public Star Night on the third Friday, when doors open at 7:00 PM followed by a 7:30 PM presentation before the domes open for viewing. Park in the main lighted high school lot just east of the building, as the handful of spots right by the domes fill up immediately. The vibe inside is welcoming and strictly amateur-driven, with knowledgeable volunteer astronomers queueing up targets across the 24-inch scope and smaller secondary instruments. The catch is that everything depends on the weather; overcast skies cancel stargazing, and because the telescope domes must match the outdoor temperature, unheated rooms turn freezing fast on Front Range nights—so dress in heavy layers even if the daytime drive was warm.
The move: Arrive for the free Public Star Night (third Friday of the month, doors open 7 pm, program at 7:30 pm) — listen to a short talk from a volunteer astronomer, then take turns at the 24-inch Apollo-era scope to view planets, nebulae, or star clusters, and ask the staff to tell you the story of how the telescope helped choose where the Apollo landers would touch down.
📍 Before you go The observatory hides on the east grounds of Berthoud High School — a blue building with two white domes, tucked behind the school near the running track, so you won’t see it until you’ve nearly passed the campus on this small-town drive north of Denver. Park in the big lighted high-school lot just east of the school, since the few spaces by the domes fill fast. The public star nights are walk-in (no reservations), but everything rides on clear skies — check the forecast and dress warm, as Front Range nights turn cold quickly. Pair it with a daytime loop around nearby Carter Lake.
- 📍 Berthoud
- 💸 $
- ⚡ Up for anything
- 🌗 Indoors
Where: 850 Spartan Ave, Berthoud, CO 80513
Hours: Mined 2026-06-07 — confirm current hours before you go.
Pair it with
- The Speakeasy (Imperial Hotel basement) — Cap off a night of staring into deep space with a craft drink inside an authentic 1881 subterranean speakeasy less than ten miles south in Longmont.
- Mon Ami Salt Cave & Spa — Relax under a fiber-optic artificial star ceiling set into 3,000 pounds of Himalayan salt before viewing the real cosmos through a 24-inch scope six miles north.
- Faces Bridge — Pair an evening at an Apollo-era telescope with a daytime stroll along the Big Thompson River trail to spot dozens of bronze faces hidden under a highway bridge.
- Redman (Trail of the Whispering Giants) — Combine your night sky outing with a quick roadside stop to see a 37-foot folk-art head carved from a single cottonwood tree in nearby Loveland.
Good to know
How much does it cost to attend a Public Star Night?
Public Star Nights are completely free, with no tickets or reservations required.
When are the public stargazing nights scheduled?
Free Public Star Nights happen on the third Friday of every month. Doors open at 7:00 PM, a guest speaker presentation begins at 7:30 PM, and telescope viewing runs from roughly 8:30 PM to 10:00 PM.
Where is the observatory located on the high school grounds?
The observatory sits on the east grounds of Berthoud High School at 850 Spartan Ave, tucked behind the school near the running track.
What happens if the weather is cloudy or stormy?
Telescope viewing requires clear skies and will be cancelled in bad weather, though scheduled indoor presentations and talks may still proceed.
Plan a visit & invite your people →
Further reading: starkids.org · Tripadvisor
last checked: 2026-06-07