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Phil Harrington's Cosmic Challenge Archives

Cosmic Challenge: Seyfert's Sextet

Jul 06 2020 03:00 PM | PhilH in Phil Harrington's Cosmic Challenge

Seyfert's Sextet, known to many as Hickson Compact Galaxy Group 79, is a tight gathering of galaxies in the northern corner of Serpens Caput. Serpens Caput is the western segment of this bisected constellation, marking the triangular head of the serpent that Ophiuchus is handling. Observing Seyfert's Sextet has been one of my pet projects for years. It's a fun little galactic rat pack for summer outings before we plunge headlong into the summer Milky Way.

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Cosmic Challenge: Rupes Recta (Straight Wall), Huygen's Sword, Birt, and Rima Birt

Jun 01 2020 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

What is your favorite lunar feature? Maybe it's the mighty craters Copernicus or Tycho. Or could it be the historic Sea of Tranquility? Perhaps you enjoy visiting the rugged southern highlands around Clavius, or the Apennine and Alp Mountains. If I had to come up with my favorite target, it would have to be a far more modest sight. I always enjoy looking for and at the Straight Wall.

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Cosmic Challenge: Two Pairs

May 01 2020 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Most agree that the Messier catalog of deep-sky objects stands as the finest single compilation of star clusters, nebulae, and galaxies visible from the northern hemisphere. When it comes time to single out the finest of the list's 109 entries, however, we often have trouble agreeing. Is it the Orion Nebula, M42; the Great Globular Cluster, M13; or maybe the Ring Nebula, M57? So many choices! One thing is for certain -- you'll never find Messier's 40th entry on anyone's "finest" list.

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Cosmic Challenge: Leo Trio 2

Apr 01 2020 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

You have undoubtedly heard of the Leo Trio, made up of M65, M66, and NGC 3628. But how about the Leo Trio 2? The Leo Trio 2 are tucked snuggly into the constellation's northernmost quadrant, some 7° north of the Leo "sickle."

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Cosmic Challenge: Arp 82

Mar 01 2020 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

The constellation Cancer the Crab may not be much to look at, but it holds some fascinating objects within its emaciated body. Case in point: Arp 82, the 82nd entry in Halton Arp's Atlas of Peculiar Galaxies. Made up of NGC 2535 and NGC 2536, Arp 82 is a strange pair that seems to be experiencing a galactic version of arrested development.

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Cosmic Challenge: NGC 1535

Jan 01 2020 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Planetary nebula NGC 1535 is a victim of circumstance. Take a look at its facts. Its bluish disk spans about a minute of arc, which is quite large as planetaries go, and shines brightly enough to be visible through giant binoculars. Its central star glows at magnitude 11.6, creating a surreal scene resembling a disembodied human eye, which led to the nickname "Cleopatra's Eye." Those in the know rate NGC 1535 as one of the sky's finest planetary nebulae. Yet this enticing target remains unknown to many backyard stargazers.

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Cosmic Challenge: February 2020 NGC 2298

Feb 01 2020 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Although most globular clusters line the summer sky as they huddle around the core of our galaxy, there are a few renegades that have stepped out on their own to occupy regions far beyond the rest. One such globular, nestled behind the rich Milky Way star fields of Puppis, is NGC 2298.

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Cosmic Challenge: NGC 1 and NGC 2

Dec 01 2019 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

As 2019 draws to an end, let's talk about a first. I am always interested in seeing the first of anything, whether it's the first day of a new year, the opening day of baseball season, the first robin of spring, the first snowflake of winter, or the first object in a particular deep-sky catalog. In the case of the latter, NGC 1, along with NGC 2, create our final challenge of the year.

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Cosmic Challenge: Satellites of Uranus

Nov 01 2019 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Of the 27 known satellites in the Uranian family, four stand out, just as the four Galilean satellites do among the Jovian clan. William Herschel discovered the first two Uranian moons on January 11, 1787, six years after he had discovered the planet itself. The next two remained undetected until the British astronomer William Lassell (1799-1880) spotted them on October 24, 1851. It is these four that we hope to catch through our own telescopes.

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Cosmic Challenge: The Deer Lick Group

Oct 01 2019 05:03 AM | PhilH in Phil Harrington's Cosmic Challenge

The autumn sky abounds with little bundles of galaxies scattered throughout its stars. One of the best known is the group of 7 galaxies that surround the magnificent spiral NGC 7331 in Pegasus, the Flying Horse. An observer could easily spend an hour or more just soaking in all that this small patch of sky has to offer.

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Cosmic Challenge: Emission Nebula Simeis 57

Sep 01 2019 10:16 AM | PhilH in Phil Harrington's Cosmic Challenge

Simeis 57 is one of the most intriguing emission nebulae in the late summer sky, yet it is almost unknown to visual observers. Photographers, however, know it as a pair of opposing arcs of reddish light, one extending to the north, the other to the south, that appear to be spinning symmetrically away from a common center. Its unusual appearance has led to its two nicknames: the Propeller Nebula or the Garden Sprinkler Nebula.

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Cosmic Challenge: Planetary nebula IC 4732

Aug 01 2019 04:55 AM | PhilH in Phil Harrington's Cosmic Challenge

M22 is right in the thick of it, not far from the galactic center of the Milky Way. As such, it has lots of company. One particular planetary nebula proves a worthy adversary through 10- to 14-inch scopes: IC 4732. IC 4732 lies just 1.4° north-northwest of M22. Cataloged at magnitude 12.1, its tiny disk is difficult to pick out from the mob of field stars -- difficult, but not impossible.

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Cosmic Challenge: Lunar craters Armstrong, Aldrin, and Collins

Jul 05 2019 11:22 AM | PhilH in Phil Harrington's Cosmic Challenge

Last month, I challenged you to find all six of the Apollo landing sites. This month, to commemorate the 50th anniversary of Neil Armstrong's and Edwin Aldrin's historic landing and moon walk, we return to Mare Tranquilitatis, the scene of Apollo 11, to find three small craters that bear the names of that historic mission's crew members.

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Cosmic Challenge: Apollo Landing Sites

May 31 2019 11:46 AM | PhilH in Phil Harrington's Cosmic Challenge

Between July 1969 and December 1972, six teams of United States astronauts ventured across the gap between Earth and Moon to land and walk on that distant world. Have you ever visited their landing sites? If not, let's do so now.

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Cosmic Challenge: M51's spiral arms

Apr 30 2019 07:52 AM | PhilH in Phil Harrington's Cosmic Challenge

Of the thousands of spiral galaxies visible through backyard telescopes, one stands above the rest in terms of visual interest: M51, the famous Whirlpool Galaxy in Canes Venatici. Everything adds up in M51's favor. We are seeing it very nearly face-on, its spiral arm halo is bright and peppered with star clouds and vast regions of nebulosity, and it brings with it a friend in the form of a smaller companion galaxy that can even be seen through giant binoculars.

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Cosmic Challenge: Leo III

Mar 30 2019 09:54 AM | PhilH in Phil Harrington's Cosmic Challenge

A springtime rite of passage started here two years ago. It started in the April 2017 edition of this e-column, when I challenged readers to find the dwarf galaxy Leo I. Leo I is one of many dim dwarf galaxies gravitationally bound to the Milky Way. The fact that its surface brightness rates only 15th magnitude, coupled with its position just 20' north of Regulus makes Leo I a tough challenge to land.

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Cosmic Challenge: NGC 2363 and NGC 2366

Feb 28 2019 04:59 PM | PhilH in Phil Harrington's Cosmic Challenge

Will the real NGC 2363 please stand up? For years, there has been an ongoing debate over the true identity of the 2,363rd entry in the New General Catalog.

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Cosmic Challenge: Sharpless 2-301

Feb 01 2019 02:39 PM | PhilH in Phil Harrington's Cosmic Challenge

While a few of Sharpless's entries, such as Sh2-25 (better known as M8, the Lagoon Nebula) and Sh2-49 (M16, the Eagle Nebula), are well known to visual observers, most are among of the most challenging objects to see visually. If you have never made a concerted effort to see some of the lesser known Sharpless objects, then this challenge, Sh2-301 in Canis Major, is a good introduction to the sport.

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Cosmic Challenge: Jonckheere 320

Jan 01 2019 06:04 AM | PhilH in Phil Harrington's Cosmic Challenge

On January 22, 1916, while revisiting some of the stars in his Catalog and Measures of Double Stars discovered visually from 1905 to 1916 within 105° of the North Pole and under 5" Separation, French astronomer Robert Jonckheere returned to a vague double in Orion, which he had previously designated as entry number 320. Jonckheere was later to write of this encounter through the 28-inch refractor at the Royal Greenwich Observatory, "I noticed that the object I have catalogued as J 320 is not a double star, but, like J 475, it appears with the larger instrument to be an extremely small bright elongated nebula. As is the case with J 900, this object also appears to be new as a nebula."

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Cosmic Challenge: Globular clusters in M31

Dec 01 2018 06:00 AM | PhilH in Phil Harrington's Cosmic Challenge

The Andromeda Galaxy, M31, was probably one of the first galaxies you ever saw first-hand. It was mine. That was all way back in 1969. Since then, I have grown to appreciate it as far more than just the ill-defined oval blur I drew in my logbook. But in 1969, the thought of looking for individual objects within M31 never crossed my mind.

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Cosmic Challenge: NGC 147 and NGC 185

Nov 04 2018 08:46 AM | PhilH in Phil Harrington's Cosmic Challenge

M32 and M110 are nice challenges for handheld binoculars. Most amateurs are familiar with them, since they lie in the same field of view of the parent Andromeda Galaxy. But two others, designated as NGC 147 and NGC 185, are not as nearly well known. Both are several degrees to M31's north, across the border in Cassiopeia and feature smaller, fainter disks that are much more challenging to see.

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Cosmic Challenge: Einstein's Cross

Oct 01 2018 08:53 PM | PhilH in Phil Harrington's Cosmic Challenge

From an aesthetic perspective, the most perfect gravitational lens is Einstein's Cross, formed by the galaxy PGC 69457 (cross- cataloged as CGCG 378-15) and the quasar QSO 2237+0305 in Pegasus. PGC 69457 is also known informally as Huchra's Lens after its discoverer, John Huchra, professor of cosmology Harvard University. Current estimates place this small, otherwise unspectacular spiral galaxy at 400 million light years away. The quasar lurks far behind at an incredible distance of 8 billion light-years. Were it not for gravitational lensing, the quasar would remain hidden by the galaxy, as the two are nearly in-line as seen from Earth. But as it is, Huchra's lens fractures the ancient light from the quasar into four separate paths that slide around the galaxy just as water flows around a rock in a stream. The end result is not one, but four ghostly images of QSO 2237+0305 surrounding the nucleus of PGC 69457 in a practically perfect diamond pattern.

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Cosmic Challenge: North America Nebula (NGC 7000)

Sep 01 2018 05:07 PM | PhilH in Phil Harrington's Cosmic Challenge

The North America Nebula (NGC 7000) is a large expanse of glowing hydrogen gas mixed with opaque clouds of cosmic dust just 3° east of Deneb [Alpha (α) Cygni] and 1° to the west of 4th-magnitude Xi (ξ) Cygni. Famous as one of the most luminous blue supergiants visible in the night sky, Deneb marks the tail of Cygnus the Swan, or if you prefer, the top of the Northern Cross asterism.

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Cosmic Challenge: Campbell's Hydrogen Star

Jul 31 2018 06:56 PM | PhilH in Phil Harrington's Cosmic Challenge

American astronomer William Wallace Campbell spotted this unusual star-like object through a visual spectroscope at Lick Observatory in 1893. He could tell immediately from its spectrum that, despite its stellar appearance, he was not seeing an ordinary star at all. Instead, he had spotted an uncharted planetary nebula.

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Cosmic Challenge: Dissecting M101

Jul 01 2018 05:22 AM | PhilH in Phil Harrington's Cosmic Challenge

Just spotting the gigantic Pinwheel Galaxy, M101, can sometimes be challenging enough. Its low surface brightness can drive suburban observers crazy, especially when we see photographs that show it so big and bright, or that it is listed as 8th magnitude. It all comes down to surface brightness, or more accurately, lack of surface brightness. Seeing the dim glow of the galaxy's small core, or the even dimmer glimmer of the surrounding spiral arms, can take a concerted effort. But with time and patience, M101 is visible, with difficulty, through 50-mm binoculars even given a suburban sky with a naked-eye limiting magnitude of perhaps 4.5.

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