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Phil Harrington's Cosmic Challenge Archives

Cosmic Challenge: M13's propeller

Jul 01 2017 09:33 AM | PhilH in Phil Harrington's Cosmic Challenge

In last month's column, we paid a visit to the Moon and the crater pair of Messier and Messier A. This month, we head back out into deep space to examine one of the most spectacular entries in Charles Messier's catalog: M13, the Great Hercules Globular Cluster.

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Cosmic Challenge: Lunar Craters Messier and Messier A

May 31 2017 01:20 PM | PhilH in Phil Harrington's Cosmic Challenge

Summer is in the offing here in the Northern Hemisphere and the longest day of the year is at hand. While many of us enjoy the warmer weather, the dark of night comes late in the evening and leaves all too early the following morning. So while deep-sky observing is limited, we can still enjoy viewing our Moon even if the sky is still bright. Yes, observing challenges await us on our nearest neighbor in space.

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Cosmic Challenge: The Antennae

May 01 2017 12:45 PM | PhilH in Phil Harrington's Cosmic Challenge

Seven decades ago, while scanning a Palomar Sky Survey plate of the area around brilliant Regulus in Leo the Lion, astronomers Robert Harrington (no relation) and A.G. Wilson noticed a faint blur of light just 1/2° north of the star. They may have thought at first that the glow was just an internal lens flare caused by stray starlight, but it soon became apparent that they had discovered something very real.

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Cosmic Challenge: Leo I

Apr 01 2017 11:21 AM | PhilH in Phil Harrington's Cosmic Challenge

Seven decades ago, while scanning a Palomar Sky Survey plate of the area around brilliant Regulus in Leo the Lion, astronomers Robert Harrington (no relation) and A.G. Wilson noticed a faint blur of light just 1/2° north of the star. They may have thought at first that the glow was just an internal lens flare caused by stray starlight, but it soon became apparent that they had discovered something very real.

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Cosmic Challenge: Jonckheere 900

Mar 04 2017 08:03 AM | PhilH in Phil Harrington's Cosmic Challenge

Few amateur astronomers are familiar with the name Robert Jonckheere. Jonckheere was a French double-star observer who conducted research at a number of observatories over his six-decade career, including the Strasbourg Observatory in France, the Royal Greenwich Observatory in England, as well as McDonald Observatory in Texas.

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Cosmic Challenge: A Case of Mistaken Identity

Feb 04 2017 07:53 AM | PhilH in Phil Harrington's Cosmic Challenge

There once was a mystery in Lynx. The story opened in 1790 when William Herschel discovered a small, nebulous glow about 2½° northwest of 27 Lyncis. He later added it as number 830 in his list of "very faint nebulae" (abbreviated H-III-830) and apparently moved on without noticing a second, fainter blur of light just to the northeast. That second object was discovered 66 years later by William Parsons, 3rd Earl of Rosse, through his 72-inch "Leviathan" reflector. Both were later incorporated into John Dreyer's New General Catalog. NGC 2474 is described as "faint, pretty small, extended?, brighter middle, very small star?, large star north following." NGC 2475 is simply noted as "makes a double nebula with" NGC 2474.

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Cosmic Challenge: Barnard's Loop

Dec 31 2016 08:20 AM | PhilH in Phil Harrington's Cosmic Challenge

One of the greatest naked-eye challenges goading amateur astronomers around the world is trying to spot the elusive arc of nebulosity known as Barnard's Loop. Cataloged officially as Sharpless 2-276, Barnard's Loop is a ghostly, 10°-wide semicircular bow of nebulosity that wraps around the eastern side of Orion, the Hunter. In long exposure photographs, it bears the unmistakable resemblance to portions of the Veil Nebula supernova remnant in Cygnus. Spotting it by eye stands as a monumental test for observers.

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Cosmic Challenge: Globular Clusters in the Fornax Dwarf Galaxy

Dec 03 2016 07:13 AM | PhilH in Phil Harrington's Cosmic Challenge

Let's begin this challenge with a riddle. What's big and round, close at hand, and yet nearly impossible to see? If you answered "the Fornax Dwarf Galaxy," then you are correct! The Fornax Dwarf, a dwarf spheroidal system, covers a 17'x13' area of our late autumn sky and lies about 530,000 light years from the Milky Way. That's well within the confines of our Local Group of galaxies. And with a magnitude rating of 9.3, it sounds like it should be bright and easy to see. But when we look its way, it's not there. Even the best photos manage to record only an incredibly dim, elliptical haze peppered by some 19th-magnitude stars!

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Cosmic Challenge: IC 5146 and B168

Oct 29 2016 08:17 AM | PhilH in Phil Harrington's Cosmic Challenge

As a group, emission nebulae, or Hydrogen-II regions, are the most difficult deep-sky objects to see visually. The problem is that they radiate light in very narrow segments of the visible spectrum, with their brightest emissions in the red wavelengths. As luck would have it, the human eye is all but color blind to red light under dim light conditions. Arguably, the only objects more difficult to spot than emission nebulae are the opaque profiles of dark nebulae. These cosmic dust clouds are themselves invisible; we only see their silhouettes against the starry backdrop. No starry backdrop, no dark nebula; it's that simple. And that brings us to this month's double challenge in Cygnus. IC 5146, known to many by its nickname, the Cocoon Nebula, is a taxing patch of glowing gas, while Barnard 168 is a thin, sinuous lane of darkness that seems to start at the nebula and extend far to its northwest.

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Cosmic Challenge: Pease 1

Oct 01 2016 03:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Of the more than 130 globular clusters gravitationally linked to our Milky Way galaxy, only four are known to contain planetary nebulae.  The best known example of a planetary/globular pairing is Pease 1 found within M15 in Pegasus.  That's this month's Cosmic Challenge.

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Cosmic Challenge: NGC 6886 and NGC 6905

Aug 29 2016 08:52 AM | PhilH in Phil Harrington's Cosmic Challenge

Last month, I offered up two planetary nebulae for smaller apertures. This month, we again hunt for a pair of planetaries. This time, however, we may need a little more oomph to get the job done.

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Cosmic Challenge: NGC 6803 and NGC 6804

Aug 07 2016 07:40 AM | PhilH in Phil Harrington's Cosmic Challenge

Here's a two'fer for you, a pair of challenges found within 1° of each other in the constellation Aquila the Eagle. Both of these planetary nebulae present interesting tests for smaller apertures, each in its own way.

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Cosmic Challenge: Galaxies around M13

Jun 26 2016 11:00 AM | PhilH in Phil Harrington's Cosmic Challenge

If you're like me, you have probably seen Jupiter, Saturn, the Orion Nebula, and all of the sky's showpiece objects more times than you can count. And while they are truly spectacular and well worth revisiting, you may be looking for something new, something challenging to observe.

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