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Phil Harrington's Cosmic Challenge Archives

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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