Cosmic Pursuits

Basic astronomy and night sky information

Recent Astronomy Articles at Cosmic Pursuits

IC 4665, the “HI” Star Cluster

by Brian Ventrudo Filed Under: Deep Sky

The open star cluster IC 4665 in the constellation Ophiuchus.
The open star cluster IC 4665 in the constellation Ophiuchus (credit: Wikipedia)

One of the best targets for a quick stargazing session this time of year is the pretty but underappreciated open star cluster IC 4665. It’s a snap to find, beautiful to behold, and like most sky sights on Cosmic Pursuits, it’s visible from the northern and southern hemispheres.

IC 4665 is spread out over a full degree, more than twice the diameter of the full Moon, so it looks fainter than its integrated magnitude of 4.7. In dark sky, IC4665 is just barely visible to the unaided eye roughly 1° NE of the star Celebrai in the constellation Ophiuchus. Celebrai, or β (beta) Ophiuchi, is one of the stars in the distinctive asterism called Taurus Poniatowski, the “little bull”. If you’re battling light pollution, you’ll need binoculars to spot the cluster [Read more…] about IC 4665, the “HI” Star Cluster

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Noctilucent Clouds – Marvels of the Mesosphere

by Brian Ventrudo Filed Under: Atmospheric Sightings

Noctilucent clouds over the Baltic Sea as viewed from Laboe, Germany. Image credit: Matthias Süßen under Creative Commons BY-SA 4.0.

At higher latitudes, on some midsummer nights, long after the sun has dipped below the horizon, a ghostly silver-blue lacework appears low over the northern horizon. These ethereal wisps are noctilucent clouds — the highest clouds on Earth – and among the most visually striking phenomena in the night sky. Their name comes from the Latin for “night-shining,” and they appear exactly as that: illuminated clouds light shimmering in the dark where no light should be [Read more…] about Noctilucent Clouds – Marvels of the Mesosphere

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Hopping Galaxies in the Bear’s Den

by Joe Bergeron Filed Under: Deep Sky

The galaxies M82 (lower left) and M81 in the constellation Ursa Major. Image credit: Joe Bergeron.

So many galaxies, so little time! A good place to begin an evening of galaxy hopping on a northern spring or summer night is with the Messier galaxies M81 and M82 in the constellation Ursa Major (see above). Conveniently located by drawing a line through the Big Dipper stars Phecda and Dubhe and extending it an equal distance beyond the Big Dipper asterism, this is probably the finest galaxy pair in the sky. Separated by just 38 arc-minutes, both fit into the low power field of a small telescope. With a 22mm Panoptic eyepiece in my 8″ EdgeHD telescope, I had 93x and a field of view of 45 arc minutes, so I had to slew the mount a little from one to the other to see them both well [Read more…] about Hopping Galaxies in the Bear’s Den

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A Dazzling New View of the Sombrero Galaxy

by Brian Ventrudo Filed Under: Science

Messier 104, nicknamed the Sombrero galaxy, is a popular target for amateur observing and astronomical research. Its recognizable extended halo and dust-filled disk are captured in this image from the Department of Energy-fabricated Dark Energy Camera (DECam) mounted on the U.S. National Science Foundation Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO) in Chile, a Program of NSF NOIRLab.

The Sombrero Galaxy (Messier 104) offers a fine view for visual observers and imagers. This nearly edge-on spiral galaxy about 30 million light years away in the Virgo galaxy cluster shows a smoky lane of interstellar dust finely etched against a brilliant galactic disk and unusually bright halo. This new image from the Dark Energy Camera on the Victor M. Blanco 4-meter telescope at CTIO in Chile shows an immense halo of stars around the galactic plane along with a loop of stars (lower right), all of which likely came from smaller galaxies gobbled by this big spiral. The galaxy contains some 2,000 globular clusters, nearly twenty times as many as our Milky Way. It’s a beautiful image to behold.

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NEAF 2026 Overview and Recap

by Brian Ventrudo Filed Under: Astronomy Equipment

The Northeast Astronomy Forum and Space Expo (NEAF) was held as usual this month at Rockland Community College in Suffern, New York. This forum features exhibits from gear suppliers for amateur astronomers from around the world and offers stargazers a chance to see the latest tools and mingle in a convivial atmosphere just as spring and warmer weather arrives. Many would like to go, but not everyone can manage the trip. But Luca Bartek (Space Koala) produced two excellent videos in which she tours the exhibition and talks to astro-vendors about their latest offering. Both of her videos below capture the highlights of Day 1 and Day 2 of the show…
[Read more…] about NEAF 2026 Overview and Recap

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