Cosmic Pursuits

Basic astronomy and night sky information

astrophotography

The Crescent Nebula

By Filed Under: Deep Sky

A bi-color image of NGC 6888, the Crescent Nebula, by Terry Hancock. The total integration time for this image was 18 hours.
A bi-color image of NGC 6888, the Crescent Nebula, by Terry Hancock. The total integration time for this image was 18 hours.

The Crescent Nebula, located near the middle star that marks the heart of the constellation Cygnus, is a complex arc of gas that’s powered by the machinations of a massive dying star. Called WR 136, this star is just 4-5 million years old, but it’s big enough to have quickly burned through its store of fuel in its core and has now entered a stage where it sheds mass from its outer layer at a prodigious rate, nearly one full solar mass every 10,000 years. This fast-moving hot gas, which moves at a speed of 2,000-3,000 km/s, collides with cooler gas ejected by the star during its quieter days, and the collision excites the gas to emit light. Massive and mass-losing stars like WR 136 are called Wolf-Rayet stars. There are only about 150 such stars known in the Milky Way [Read more…] about The Crescent Nebula

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A View of New Star Cluster and Nebula

By Filed Under: Deep Sky

Image of open star cluster and emission nebula NGC 6823 and NGC 6820 in the constellation Vulpecula (credit: Jeff Johnson)
Image of open star cluster and emission nebula NGC 6823 and NGC 6820 in the constellation Vulpecula (credit: Jeff Johnson)

Within the Summer Triangle, in the constellation Vulpecula, the Fox, lies a fairly new star cluster NGC 6823 embedded within the glowing gas cloud of its birthplace, the nebula NGC 6820. The image above by astrophotographer Jeff Johnson of New Mexico shows cluster and emission nebula along with a dark nebula within the brighter emission nebula that shrouds yet another round of star formation [Read more…] about A View of New Star Cluster and Nebula

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The Southern Pinwheel – M83

By Filed Under: Astronomy Images and Video, Deep Sky

Messier 83, the "Southern Pinwheel", imaged at the Star Shadows Remote Observatory. Courtesy
Messier 83, the “Southern Pinwheel”, imaged at the Star Shadows Remote Observatory. Courtesy of Warren Keller, Steve Mazlin, Steve Menaker, and Jack Harvey

Today, let’s look at the spiral galaxy M83, a lovely cosmic lotus blossom and one of the showpieces in the southern deep sky.

Barely visible from northern latitudes, M83 lies roughly 15 million light-years away in the constellation Hydra. It’s one of the 25 brightest galaxies in the sky, and one of the closest and brightest barred spiral galaxies. At magnitude 7.6, it’s easily visible with binoculars and small telescopes about 18° due south of the bright star Spica, in Virgo, and just north of the star Menkent in the constellation Centaurus [Read more…] about The Southern Pinwheel – M83

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Secrets of Nightscape Imaging – Interview with Alan Dyer

By Filed Under: Astronomy Images and Video

Nightscape of stargazers and the Milky Way through Scorpius and Sagittarius at the Texas Star Party in 2015 (by Alan Dyer)
Nightscape of stargazers and the Milky Way through Scorpius and Sagittarius at the Texas Star Party in 2015 (by Alan Dyer)

I had the great pleasure of recently interviewing the master astrophotographer Alan Dyer of AmazingSky.com to discuss the basics of nightscape imaging with a digital camera. This sort of imaging, which combines elements of landscape photography and astrophotography, has become extremely popular over the last few years thanks to the advent of large, low-noise sensors in digital SLR cameras. Alan is the author most recently of the multi-media guide called Nightscapes and Timelapses which gives a comprehensive introduction to the art and craft of nightscape imaging.

As you listen to my interview with Alan, you will discover: [Read more…] about Secrets of Nightscape Imaging – Interview with Alan Dyer

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The Eta Carinae Nebula

By Filed Under: Astronomy Images and Video, Deep Sky

The Eta Carinae Nebula (NGC 3372), the brightest star forming region visible from Earth (credit: John Mansur and Terry Hancock).
The Eta Carinae Nebula (NGC 3372), the brightest star forming region visible from Earth (credit: John Mansur and Terry Hancock).

The Eta Carinae Nebula, the jewel of the southern-hemisphere constellation Carina, the Keel, is the most spectacular example of an active star factory in all the heavens. The nebula is about 260 light years across, some seven times larger than the Orion Nebula. And while it’s 7,500 light years away, five times farther away than Orion, it’s still easily visible to the even the most casual stargazer as a large frosty patch three times as wide as the full Moon in the Milky Way west of the constellation Crux, the Southern Cross [Read more…] about The Eta Carinae Nebula

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