Observing Wolf-Rayet Stars in the Constellation Cygnus

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by John H. Bickel, Ph.D. Denver Astronomical Society, Member

What is a Wolf-Rayet star?

In 1867, French astronomers Charles Wolf and Georges Rayet using the 40 cm Foucault telescope, at the Paris Observatory [Ref. 1], discovered three stars in the constellation Cygnus (now designated HD191765, HD192103 and HD192641) that displayed broad emission bands instead of the typical absorption lines seen in most stellar spectra.… Continue reading.

What’s Up in Denver? September 21st through 27th, 2026

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Here’s a brief look at what’s going on in the Mile High City this week.

September 21: On this day in 2003, NASA ended the Galileo spacecraft’s mission by sending it into Jupiter’s atmosphere after nearly eight years exploring the giant planet and its moons.… Continue reading.

What’s Up in Denver? September 14th through 20th, 2026

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Here’s a brief look at what’s going on in the Mile High City this week.

September 14: DAS General Meeting: “A Graphical Tour of the Cosmos”w/ Dr. Ed Friedman: Free, in-person event at Secular Hub: 7:00PM Check out the waxing crescent Harvest Moon near Venus: low in the western sky in the constellation Virgo just after sunset at 8:00PM September 15: On September 15, 1966: Gemini 11 returned to Earth after a three-day mission that included rendezvous and docking with an Agena target vehicle and two spacewalks.… Continue reading.

DAS Astrophotography Gallery for September 2026

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The Denver Astronomical Society Astrophotography Special Interest Group (ASIG) July Member Gallery

Each month, the Astrophotography Special Interest Group (ASIG) of the Denver Astronomical Society gathers to share one of the most inspiring parts of our hobby—the images we’ve captured of the night sky.… Continue reading.

What’s Up in Denver? September 7th through 13th, 2026

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Here’s a brief look at what’s going on in the Mile High City this week.

September 7: Look for the waning crescent Stergeon Moon making a line with Castor and Pollux and Mars nearby in the constellation Gemini low in the eastern skies around 3:00AM until dawn.… Continue reading.

What’s Up in Denver? August 31st through September 6th, 2026

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Here’s a brief look at what’s going on in the Mile High City this week.

August 31: Look for the waning gibbous Sturgeon Moon near Saturn low in the eastern sky in the constellation Pisces around 10:30PM September 1: Catch Venus right next to Spica.… Continue reading.

Frisco Becomes Colorado’s Newest Dark Sky Community

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Colorado’s list of communities working to protect the night sky continues to grow. The Town of Frisco has officially been designated an International Dark Sky Community by DarkSky International, recognizing the mountain town’s commitment to reducing light pollution and preserving its spectacular nighttime environment.… Continue reading.

What’s Up in Denver? August 24th through 30th, 2026

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Here’s a brief look at what’s going on in the Mile High City this week.

August 24: DMNS Free Day: Free, in-person program at Denver Museum of Nature and Science: 9:00AM to close DAS E-Board Meeting: Online, member’s only event via Zoom (check Slack and membership email for details): 7:00PM August 25: China’s Change 7 robotic mission to the moon is scheduled to launch this week between August 24 and August 31.… Continue reading.

DAS Astrophotography Gallery for August 2026

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The Denver Astronomical Society Astrophotography Special Interest Group (ASIG) July Member Gallery

Each month, the Astrophotography Special Interest Group (ASIG) of the Denver Astronomical Society gathers to share one of the most inspiring parts of our hobby—the images we’ve captured of the night sky.… Continue reading.

What’s Up in Denver? August 17th through 23rd, 2026

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Here’s a brief look at what’s going on in the Mile High City this week.

August 17: 🛰️ Get a glimpse of the ISS passing across Denver’s pre-dawn sky. The International Space Station will move swiftly across the sky from the southwest to the northeast between 5:27 and 05:33AM August 18: ☄️ κ-Cygnid meteor shower peaks with their radiant near the border of Cygnus and Draco and high in the northern sky.… Continue reading.
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