Boulder.
The definitive guide to dark skies and celestial observation in Boulder, CO. Verified using National Park Service and NASA Night Sky Network Clubs data.
Quick Guide for Boulder
- Top Community Pick: Horsetooth Mtn Open Space (~39.9 miles)
- Best Scientific Reading: Bortle 5.0 at Bobcat Ridge
- Local Experts: Longmont Astronomical Society
- Verified Observations: 5 distinct spots
Searching for a clear window into the cosmos near Boulder, CO? While enthusiasts often gather at Horsetooth Mtn Open Space for its accessibility, scientific audits conducted by the National Park Service at Bobcat Ridge provide the most accurate reading of the regional sky quality, measuring at a Bortle 5.0. Atmospheric stability in the Boulder region is often influenced by local topography, which can help settle the air for high-magnification viewing.
The Best Times for Stargazing in Boulder
Since Boulder sits in a transitional light zone, viewing is best during the New Moon or after midnight when some commercial lighting is reduced.
Expert Tips for Boulder Observers
Before heading out to Horsetooth Mtn Open Space, we recommend arriving during civil twilight to scout the terrain safely. For the best views at this spot, try to observe targets when they are highest in the sky to minimize atmospheric interference. Local enthusiasts often frequent this spot, making it a great place to meet experienced observers. Regardless of your gear, allow 30 minutes for your eyes to fully dark-adapt.
Colorado Guide
Local Top Spots
Community-vetted locations known for clear horizons and accessibility for telescopes and astrophotography.
Horsetooth Mtn Open Space
" 'Dress for temperatures ~20F colder than forecast low for the night. If you need a flashlight, please cover it with red cellophane.' "
Lvld Prairie Ridge
" Standard Advice: Dress in layers as temperatures drop quickly after sunset. Use a red-light flashlight to preserve your night vision. "
Rocky Mountain National Park
" Dress for winter temperatures (heavy coat, gloves, hat)' "
Fossil Creek Reservoir
" 'Dress for temperatures ~20F colder than forecast low for the night. If you need a flashlight, please cover it with red cellophane.' "
RMNP Park&Ride
" Standard Advice: Dress in layers as temperatures drop quickly after sunset. Use a red-light flashlight to preserve your night vision. "
NPS Sky Measurements
Instrumented readings from the National Park Service Night Sky Program, providing the most accurate SQM and Bortle classifications.
Bobcat Ridge
Fort Collins Natural Area
"Bobcat Ridge is a relativly dark site close to very bright population centers. One or two small clouds to the north, moving southeast. Transparency was good, seeing fair. Fort Collins light dome was bright and dominated the east horizon, while Loveland was easily visible to the southeast. Milky Way was visible as a complete arc,above the light domes, but fine detials were washed out. SQM 20.86"
Coyote Ridge
Fort Collins Natural Area
"Resolution Testing. 3 data sets collected in order to determine vertical and horizontal illuminance"
International Dark Sky Parks
Premier locations certified for their exceptional dark sky quality and commitment to light pollution mitigation.
Town of Breckenridge, Colorado
The Town of Breckenridge sits at 9,603 feet above sea level in Colorado’s Rocky Mountains, just west of the Continental Divide…
Jackson Lake State Park
This park is an “Oasis in the Plains,” for swimming, boating, fishing and waterskiing. But that’s not all…
Local Astronomy Clubs
Connect with experts and fellow enthusiasts through local astronomical societies and community groups.