Recent Astronomy Articles at Cosmic Pursuits

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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The Sky This Month – October 2017

September 30, 2017 by Brian Ventrudo Filed Under: Celestial Events

An Orionid meteor, a tiny sliver of Comet Halley, falls into the Earth’s atmosphere in October 2012. Credit: NASA.

If the weather holds, October is a lovely month for stargazing. The Milky Way still lingers in the west along with stars that were prominent in the northern summer. The autumn stars dominate overhead, and the northern winter stars are starting to poke above the eastern horizon. Best of all, you can get in a good night of stargazing without staying up too late. Early this month, there’s a wonderful pairing of planets in the eastern sky before sunrise, two meteor showers, a dramatic occultation of a bright star, another chance to see the ‘False Dawn, and your best chance of the year to see an ‘ice giant’ in the the outer solar system. Here’s what to see in the night sky this month…
[Read more…] about The Sky This Month – October 2017

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Seeing Carbon Stars, Close Up and Far

September 22, 2017 by Brian Ventrudo Filed Under: Deep Sky

his ALMA image reveals much finer structure in the U Antliae shell than has previously been possible. Around 2700 years ago, U Antliae went through a short period of rapid mass loss. During this period of only a few hundred years, the material making up the shell seen in the new ALMA data was ejected at high speed. Examination of this shell in further detail also shows some evidence of thin, wispy clouds known as filamentary substructures. Credit: ALMA (ESO/NAOJ/NRAO)/F. Kerschbaum

Many experienced stargazers are connoisseurs of carbon stars, deep-red and highly evolved stars that are dredging up carbon and other nuclear reactants from their innards on their way to becoming, briefly, planetary nebulae. These striking stars are the most colorful of all celestial sights and they’ve long intrigued astronomers who are trying to fine tune their theories of how stars come to the end of their lives. Carbon stars are too far away to reveal much detail directly, so astronomers study them indirectly by examining their spectra. But a team of researchers at the remarkable ALMA telescope in northern Chile have captured an amazingly beautiful and revealing image of a carbon star in the constellation Antlia. Let’s have a look at what they saw, then set some time aside to go see a carbon star for ourselves with a small telescope or pair of binoculars [Read more…] about Seeing Carbon Stars, Close Up and Far

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A Stroll Through the Stars of Capricorn

September 15, 2017 by Brian Ventrudo Filed Under: Deep Sky

The globular cluster Messier 30 as captured by the Hubble Space Telescope. Credit: NASA/HST.

Along the path of the zodiac, just east and a little north of Sagittarius, lies the smile-shaped constellation Capricornus. After the gaudy splendors of Sagittarius and other northern summer constellations, Capricornus isn’t much to look at. It’s the smallest constellation of the zodiac and the second-faintest after Cancer. It has just two stars brighter than 4^th magnitude, so it’s a challenge to see this constellation in the city. But Capricornus offers several splendid alignments of stars that make for excellent viewing with a pair of binoculars on nights in August through October. Let’s have a look… [Read more…] about A Stroll Through the Stars of Capricorn

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The Sky This Month – September 2017

September 1, 2017 by Brian Ventrudo Filed Under: Celestial Events

The eastern sky well after midnight in early September showing the stars of the constellations Perseus and Taurus. Credit: Brian Ventrudo.

The month of September affords stargazers a last chance to see the Milky Way and all its attendant splendors. The rich constellations of Scorpius and Sagittarius are setting for the year, moving a little westward each night, but the lengthening nights keep these stars accessible for a little longer, at least for observers in the northern hemisphere. Southern observers still enjoy the thickest part of the Milky Way almost overhead. In the east, the relatively star-poor constellations of Pegasus, Capricornus, and Piscis Austrinus are moving into view. Observers with very dark sky get the chance this month to see the zodiacal light, a faint wedge of white sunlight reflected from fine dust in the inner solar system. Also this month, low in the southwestern sky at sunset, Jupiter slowly fades from view while Saturn still hangs on, its rings casting dramatic shadows on the disk of the planet. Mercury makes its best showing of the year in the eastern sky before dawn. And the Sun crosses the celestial equator heading south, marking a change of seasons. Here’s what to see in the night sky this month…

4 Sept. Neptune reaches opposition today. This blue-green ice giant, the most distance major planet from the Sun in our solar system, shines at magnitude 7.8 and spans an apparent diameter of 2.4″. Its tiny disk is visible in the constellation Aquarius less than 1º east-southeast of the orange 4th magnitude star Hydor (λ Aquarii). While the planet is plenty bright enough to see with a telescope, or even binoculars, resolving its disk requires some magnification, at least 75x to 100x. The planet’s disk gets larger with more magnification while the images of the stars do not. Visually, the planet has a very pale blue-green color [Read more…] about The Sky This Month – September 2017

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