Tickets for a Tuesday Astronomy Night at Chamberlin Observatory go on sale at midnight, 60 days before the event, and the reservations page tells people to check daily. The monthly open house on the lawn just south of the building needs no ticket and no reservation, and it's free.
Both events use the same telescope, a 20-inch Alvan Clark-Saegmuller refractor. It saw first light in 1894 inside a red sandstone building in the middle of Observatory Park. From October through December, the free event also starts earlier each month as sunset moves earlier. For anyone living a few blocks from 2930 E. Warren Avenue, the darkest months are the easiest time to get a look.
The Denver Astronomical Society runs a mini star party on Chamberlin's south lawn once a month. Weather permitting, visitors can look through the observatory's 20-inch refractor and through telescopes that members set up on the grass. The event pages call it a free family activity and say plainly that no tickets or reservations are required.
Here is the fall schedule as posted on the DAS event pages:
| Date | Posted hours | Event title |
|---|---|---|
| Saturday, Oct. 17, 2026 | 6:45 to 9:45 p.m. | Open House: Neptune! Saturn! |
| Saturday, Nov. 14, 2026 | 5:15 to 9:15 p.m. | Open House: Neptune! Saturn! Uranus! |
| Saturday, Dec. 12, 2026 | 5:00 to 9:00 p.m. | Open House |
| Saturday, Jan. 16, 2027 | Not yet posted | Open House: Neptune! Saturn! Uranus! Jupiter! |
From October to December the start time moves up by an hour and three quarters. The December 12 open house begins at 5 p.m. and wraps up by 9. That fits an evening with young kids, or a weeknight-tired household that wants to be home at a normal hour. The planets in the titles add up as the season goes on. October lists two, November three and January four. The event descriptions themselves talk about general sky viewing, weather permitting, and don't promise particular targets.
One housekeeping note: the descriptions on these event pages repeat a template line that mentions "Saturday, July 18th." Go by the date and hours shown for each occurrence, which are what the table above uses.
The open house runs in two stages. The October 17 event page says lawn activity starts at dusk and tours of the Chamberlin building begin after dark. Members set up their own telescopes before it gets fully dark, and visitors are welcome to look through them. Anyone who owns a telescope they haven't figured out yet is invited to arrive early, bring it along and ask members for help while they set up.
That early slot is especially useful from November on. A household that got a telescope it never quite learned to use can bring it to a 5:15 p.m. start on November 14. Members will already be on the grass with their own gear.
Everything depends on the sky. DAS describes the open houses as outdoor events that depend on the weather. In January 2026 it posted a notice canceling an open house because the forecast called for extreme cold and snow. The society doesn't publish a specific cancellation threshold. For the December and January dates, check the DAS site the afternoon of the event.
The open house happens once a month. Astronomy Nights happen most weeks, on Tuesday and Thursday evenings and some Saturdays. Each one opens with a multimedia presentation by a DAS lecturer, followed by time at the 20-inch telescope if the weather allows. Tickets cost $10 for adults and $7 for children. For safety reasons, children must be at least 42 inches tall. From September through March, events begin at 7:30 p.m. Between April and August they begin at 8:30.
The DAS reservations page lays out how tickets are released:
Against today's date of October 9, here's how that works out. The 60-day window has already opened for every Astronomy Night through about December 8. That includes the October 15 and October 20 nights on the DAS calendar. October's held-back batch went out on October 1. The next two second chances come on the mornings of November 1 and December 1. Those are also the mornings any open Saturdays get added. Fall Saturdays tend to have more openings than spring and summer ones, since the page notes that open dates are "less common in spring and summer."
The page also includes a warning. Tickets can't be transferred except through the DAS reservations team. Nobody gets in unless at least one person in the group is on the official guest list, and the page warns about online scammers. If a neighbor's kid can't go, giving the ticket to someone else has to be arranged with the reservations team. A resale listing won't work.
A cloudy night isn't a lost night at Chamberlin. According to the reservations page, visitors on cloudy Astronomy Nights still learn about the telescope and get a tour of the observatory. The tour covers its clocks, the meridian telescope, the library, the wall displays and an animated video of that month's night sky.
The building gives that tour plenty to talk about. The University of Denver's history of the observatory says construction of the Romanesque red sandstone structure started in 1890 and the telescope saw first light in 1894. When it was built, its refractor was the fifth-largest of its kind in the world. DU names Humphrey Chamberlin, a Denver real estate developer, as the man who pledged $50,000 toward construction in 1888. Prof. Herbert Howe, who founded DU's astronomy department in 1880, designed the astronomical parts of the building. The DAS reservations page describes the instrument as 28 feet long with a 20-inch aperture.
History Colorado's register entry gives the observatory's National Register of Historic Places date as March 27, 1980. DU separately notes renovations in 2008.
So the telescope a visitor looks through on a clear December evening is the same instrument that first pointed at the sky over Denver in 1894. On a cloudy evening, the 132-year-old building itself is what visitors see.
The first open house of the fall comes at the end of a construction week nearby. The city's Buchtel Boulevard and Evans project began in July 2026. It adds protected bike lanes, sidewalks and crossings along Buchtel and rebuilds the intersections at University, St. Paul and Colorado. The Department of Transportation and Infrastructure's current weekly notice schedules a full closure of Buchtel between University and St. Paul from October 11 through October 17, with access to driveways and businesses kept open.
That closure window ends the same day as the 6:45 p.m. open house. Anyone who usually drives to Observatory Park on Buchtel should check the city's project page before heading out. The page carries a section on weekly impacts and work, and the city expects the full project to wrap up in late 2027. Neighbors close enough to walk won't need to worry about it.
The observatory also hosts one event this season that has nothing to do with the dark. The University Park Community Council lists its Sing and Sleigh Bells event at the Observatory Park observatory on December 6, from 3 to 5 p.m., free for residents.
That makes December the busiest month on the observatory calendar for people who live nearby. The community council's afternoon event comes on the 6th, the free DAS lawn night starts at 5 p.m. on the 12th, and the ticketed Astronomy Nights have their held-back release on the morning of December 1. The January 16 open house is already on the DAS calendar, and its title adds Jupiter to the list.
New doctors, nurses and their families who've just moved to University Park are often working schedules that rule out booking anything 60 days ahead. A free lawn night that starts at 5 p.m. and needs no reservation can be a good first outing. If you're planning a move to this part of Denver and want help getting settled, including a local calendar that fits around call schedules, Steve Charlett is glad to help. Contact Us.
