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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.

The Cat’s Eye Nebula

November 8, 2018 by Brian Ventrudo Filed Under: Deep Sky

An image of the Cat’s Eye Nebula captured with the Hubble Space Telescope. Image credit: NASA.

Unlike galaxies and star clusters and even emission nebulae, the class of objects known as planetary nebulae exist on a scale of space and time that’s comprehensible, relevant, and compelling to most humans.

Comprehensible because these tenuous exhalations of dying stars are roughly the size of a solar system, which means light can pass from one end of the nebula to the other in just a few hours, and even our current spacecraft could cross some of these nebulae in a matter of years.

Relevant because our own Sun will expire after creating its own planetary nebula in a few billion years when our star’s inner core boils off its outer layers in an intermittent nuclear frenzy.

And compelling because as you observe these objects with your telescope, you may be witnessing the death of other solar systems which once harbored intelligent civilizations that long ago passed into oblivion, or perhaps learned to travel elsewhere in the galaxy before it was too late. Amateur astronomy is, after all, a pastime of the imagination [Read more…] about The Cat’s Eye Nebula

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Filed Under: Deep Sky

A Speedy Little Double Star

September 6, 2018 by Brian Ventrudo Filed Under: Deep Sky

An image of 70 Ophiuchi by Damian Peach.

When it comes to observing the stars and other sights beyond our solar system, there’s always something new to see. But once you see it, chances are it’s not going to chance much in the coming years. That’s because things move slowly in the cosmos, at least compared to a human lifetime.

There are, however, a few exceptions. One of the most important for astronomers is the nearby binary star called 70 Ophiuchi, a little gem in the asterism known as Taurus Poniatowski in the constellation Ophiuchus. It’s a beautiful star for casual stargazers armed with a small telescope. Serious stargazers can watch over the course of a year or two to detect the motion of the two components as they slowly revolve around each other during their 88-year period. It’s one of the few double stars that make a complete revolution within the course of a human lifetime [Read more…] about A Speedy Little Double Star

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Filed Under: Deep Sky

The Blue-Green Beauty of Planetary Nebulae

May 16, 2018 by Joe Bergeron Filed Under: Deep Sky

A long-exposure image of the Helix Nebula (NGC 7293) shows far more color than can be observed visually, even through a large telescope. Image credit: Terry Hancock.

New and would-be amateur astronomers are often mystified and disappointed by the lack of color in things they see through their telescopes. And why shouldn’t they be? Popular astronomy shows, magazines, and web sites encourage people to believe that celestial objects are rich with blistering, saturated color, much like the image above. Why doesn’t that new $400 8-inch Dobsonian show bright pink nebulae, and galaxies of blue and gold? [Read more…] about The Blue-Green Beauty of Planetary Nebulae

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Filed Under: Deep Sky carbon stars, planetary nebula

Orion, Above the Belt

December 29, 2017 by Brian Ventrudo Filed Under: Deep Sky

NGC 2175, the Monkey Head Nebula. Credit: Paul Hutchinson via Flickr.

Orion is perhaps the most famous of the 88 constellations in the night sky, and it’s likely the easiest to find for stargazers all over the world.  And unlike most constellations, Orion looks like its legendary namesake: a mighty hunter with a shield, a raised arm, and a sword hanging from his star-jeweled belt. The constellation harbors some dazzling sights including what may be the most beautiful object in the night sky for a small telescope, the famous Orion Nebula, a bright blister in the nearest star-forming region to our solar system. In this little tour, we’ll have a look at some lesser-known sights in the constellation Orion north of the three bright stars of Orion’s Belt [Read more…] about Orion, Above the Belt

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Filed Under: Deep Sky constellation, orion, sky tour

Roaming the October Skies – A Brief Tour of Aquarius

October 13, 2017 by Brian Ventrudo Filed Under: Deep Sky

The Helix Nebula is a planetary nebula, a cloud of glowing gas ejected by a dying mid-sized star. (Image by Terry Hancock)

Aquarius is a dim constellation in a barren patch of sky far off the plane of the Milky Way. Just east of Capricorn, it marks the 11th constellation of the zodiac. This dim constellation lies near the other “watery” constellations including Cetus, the Sea Monster (or whale), Pisces, the Fishes, and Eridanus, the River. This ancient constellation was associated with water or water bearers since Babylonian times. Some representations have the water bearer pouring water into a stream that leads to the bright star Fomalhaut, the mouth of the southern fishes Piscis Austrinus. Like Capricorn, Aquarius has far fewer deep-sky sights than Sagittarius. But there are a handful of objects here of enduring interest including the famous Helix Nebula, one of the nearest planetary nebulae to Earth. Let’s take a short tour of some of the finer sights in this zodiacal constellation… [Read more…] about Roaming the October Skies – A Brief Tour of Aquarius

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Filed Under: Deep Sky aquarius, constellation, zodiac

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