Cosmic Pursuits

Basic astronomy and night sky information

Deep Sky Observing

Articles about how to understand, find, and see celestial objects including stars, galaxies, nebulae, and star clusters with binoculars, telescopes, and the naked eye.

Runaway Stars

by Brian Ventrudo Filed Under: Deep Sky

The runaway star AE Aurigae, above and right of center, embedded in the Flaming Star Nebula (IC 405) in the constellation Auriga.

The Flaming Star Nebula (IC405) ranks as one of the showpiece sights in the northern constellation Auriga. This glowing emission nebula gains its energy from the star AE Aurigae, a 6th-magnitude massive blue-white star about 1,500 light years away. This brilliant star, which outshines our Sun by some 30,000 times, blasts out ultraviolet light that ionizes the cloud of hydrogen gas around the star. As the hydrogen atoms reassemble, they emit light at signature wavelengths of red and green light that make these nebulae so beautiful. Most such nebulae are energized by stars that formed within their densest and most opaque regions. But that’s not the case with the Flaming Star Nebula. AE Aurigae did not originate here; it’s just passing by chance through a cold cloud of hydrogen as it hurtles through the Milky Way, far removed from the place it was born [Read more…] about Runaway Stars

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The ‘Intergalactic Wanderer’

by Brian Ventrudo Filed Under: Deep Sky

A snapshot of NGC 2419, the ‘Intergalactic Wanderer’, captured with an 85mm refractor and ZWO ASI290MM camera.

Conjured by Johann Hevelius in the late renaissance, the dim, linear constellation Lynx fills in the space between the much larger constellations Gemini, Auriga, and Ursa Major, just out of the plane of the northern Milky Way. While it doesn’t much resemble its namesake and contains no bright stars, Lynx harbors one of our galaxy’s most distant outliers, the famous ‘Intergalactic Wanderer’ (NGC 2419), a globular cluster that roams the desolate expanse between the Milky Way and the Andromeda Galaxy [Read more…] about The ‘Intergalactic Wanderer’

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Sightseeing along the Perseus Arm of the Milky Way

by Brian Ventrudo Filed Under: Deep Sky

A section of the Perseus Arm of the Milky Way looking overhead from the northern hemisphere in winter.

In the early months of each year, stargazers south of the equator enjoy a dazzling view of a rich part of the Milky Way, one that’s festooned with open star clusters, emission nebulae, and bright blue-white stars. Here, in the constellations Centaurus and Crux, we gaze into one of the two major spiral arms of the Milky Way, the Scutum Centaurus Arm, that originates from the long bar of ancient stars at the core of our galaxy.

An observer looking overhead in the northern hemisphere sees a completely different perspective. Here the view lies in a direction away from the center of the galaxy into the outer reaches of the Perseus Arm, the second major spiral arm that emanates from the galactic core [Read more…] about Sightseeing along the Perseus Arm of the Milky Way

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The Taurus Molecular Cloud

by Brian Ventrudo Filed Under: Deep Sky

The Taurus Molecular Cloud, to the lower left of the Pleiades and lower right of the California Nebula in this wide-field image. The Hyades star cluster in Taurus is at middle right; the star Capella in the constellation Auriga is the bright star at left. Image credit: Brian Ventrudo

Not far from the Pleiades and Hyades star clusters along the northern Milky Way lies the coal-black fingers of the Taurus Molecular Cloud, the nearest star-forming region to Earth. Unlike the more famous Orion star factory, with the dazzling Orion Nebula and associated bright blue-white stars, the TMC is not well known to most stargazers. That’s because it doesn’t offer much to see, with no bright nebulae and just a dark and sooty network of tendrils that span more than 30o of sky. But the TMC is the nearest star-forming region to Earth, making it of considerable interest to astronomers. It’s also a rewarding target for astrophotographers who can capture its structure against the starry background in the constellations Taurus and Auriga [Read more…] about The Taurus Molecular Cloud

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Nebula Hopping in the Constellation Cygnus

by Brian Ventrudo Filed Under: Deep Sky

The North America Nebula (on its side) and above it the Pelican Nebula in the constellation Cygnus.

Like many constellations along the arc of the Milky Way, the constellation Cygnus harbors an embarrassment of celestial riches. There’s everything here: emission nebula, supernova remnants, open star clusters, star clouds, and dark nebulae that reach like intertwined fingers over the bright and unresolved star clouds in this part of the sky. In dark sky, with a pair of binoculars or wide-field telescope, a contemplative stargazer can spend many happy hours hopping from object to object, wondering why more people turn their eyes skyward more often.

Which is what I was doing on a cool northern autumn night as I toured the celestial Swan, looking for a handful of pretty emission nebulae that radiate a deep red light and stand out along the rich star field in this part of the sky. These nebulae make ideal targets for urban stargazers like me because their contrast is readily enhanced with a good light pollution filter which passes their emission while reducing the effect of urban light pollution. The nebula doesn’t appear brighter, but it does have better contrast against fish-grey urban and suburban skies [Read more…] about Nebula Hopping in the Constellation Cygnus

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