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Phil Harrington's Cosmic Challenge Archives

Cosmic Challenge: NGC 2403

Mar 01 2024 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Hovering above the northeastern horizon at this time of year is the obscure constellation Camelopardalis the Giraffe. Though the human eye alone reveals little more than a void populated by a scattering of 4th-magnitude and fainter stars, binoculars begin to unleash some of the beast's latent wonders. One of the Giraffe's few hidden treasures that is visible through binoculars is NGC 2403, a spectacular spiral galaxy tilted nearly face-on to our perspective.

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Cosmic Challenge: Abell 12

Feb 01 2024 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Deep-sky objects can be challenging for several reasons. Some are especially faint, while others are especially small, and still others are so large that they can't fit into a single eyepiece field. Or the problem might be that a particular target is so close to another, noticeably brighter object that the light from that intruder all but obliterates the quarry. The latter problem plagues planetary nebula Abell 12. It shines at about 14th magnitude, which is not exactly bright, but is also not exceptionally dim for a telescope 10 inches (25 cm) or more in aperture. The problem, however, is that it is located a scant arcminute away from 4th-magnitude Mu (μ) Orionis. That's why it's known by the nickname the Hidden Planetary.

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Cosmic Challenge: NGC 1851

Jan 06 2024 12:13 PM | PhilH in Phil Harrington's Cosmic Challenge

I thought I'd welcome in the new year with a target that is not challenging due to its faintness, but rather due to its southern location far from any bright stars. NGC 1851 is a 7th-magnitude globular cluster in the constellation Columba, the Dove.

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Cosmic Challenge: NGC 51 Galaxy Group

Dec 01 2023 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Of the dozens of galaxy groups scattered around the autumn sky, the 136-million-light-year-distant NGC 51 group is one of the more difficult bunches to spot. Although they are not listed among Paul Hickson's compact galaxy groups, the six galaxies here are ideally placed near the zenith in early December evenings for observers at mid-northern latitudes. Its high altitude carries the group far enough above any horizon-hugging interferences that might spoil some of our other challenges.

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Cosmic Challenge: NGC 7354

Nov 01 2023 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Of the constellations that line the autumn Milky Way, King Cepheus, the king of Aethiopia in Greek mythology, is trod upon by relatively few amateur astronomers. While this is most likely because the constellation's brightest stars are faint compared to his wife, Queen Cassiopeia, the King has many royal deep-sky subjects is his own right that merit a look, including this month's challenge.

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Cosmic Challenge: The Great Square

Oct 01 2023 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Pegasus is one of the best-known autumn constellations. Depicting the winged horse that Perseus used to rescue Princess Andromeda from the clutches of Cetus the Sea Monster, Pegasus flies high in our southern sky during October and November evenings.

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Cosmic Challenge: Abell 70

Sep 01 2023 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Of the more than 80 planetaries listed by George Abell in his 1966 paper "Properties of Some Old Planetary Nebulae," Abell 70 (also known as PK38.1-25.4) is one of the most unique. Actually, the planetary itself is a stereotypical example of a ring nebula, like M57, with a round shell of gas expanding away from the dim progenitor star. But look carefully and there is clearly more here than just that.

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Cosmic Challenge: Barnard's Star

Aug 01 2023 05:03 AM | PhilH in Phil Harrington's Cosmic Challenge

The curtain opened on this challenge in September 1916, when a pair of articles written by Edward Emerson Barnard appeared in the journals Nature and The Astronomical Journal. Both recounted Barnard's discovery of a faint star in the constellation Ophiuchus that appeared completely unremarkable except for the fact that its proper motion was faster than any other star ever found.

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Cosmic Challenge: NGC 6369

Jul 01 2023 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

One of the more interesting, and at the same time, challenging of Herschel's planetaries to view through 3- to 5-inch (7.6- to 12.7-cm) instruments is NGC 6369 in southern Ophiuchus. Nicknamed the "Little Ghost Nebula," NGC 6369 is an example of a ring-type planetary nebula, a faint version of M57. That is, if you can find it.

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Cosmic Challenge: Plato's craterlets

Jun 01 2023 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

One of the great challenges facing even the most devoted lunar observers is trying to see the many small craters that dot the lava-covered floor of the walled plain Plato. Plato itself is a prominent impact scar measuring 62 miles across. It takes no more than 10x binoculars to see Plato once the Sun is up in its sky. In general, the best times to view Plato and its environs are about 1.5 days past First Quarter and again near Last Quarter.

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Cosmic Challenge: Abell Galaxy Cluster (AGC) 1656

May 01 2023 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

The Coma Galaxy Cluster, Abell Galaxy Cluster (AGC) 1656, contains more than 800 galaxies brighter than photographic magnitude 16.5. It’s a real galactic forest that will take great patience to make your way through. There is no rushing this one. Unless you have enough time to devote to the task, best to push on to another target and come back here when you do. In fact, you will never get through this huge collection of galaxies in one sitting. Or even two, three, or four sessions, for that matter. AGC 1656 could well take years before every galaxy in view is recorded and identified.

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Cosmic Challenge: NGC 2976 and NGC 3077

Apr 01 2023 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

M81 and M82 form perhaps the most famous pair of galaxies north of the celestial equator. Johann Elert Bode bumped into both quite by chance on New Year's Eve 1774. His discovery is commemorated today by M81's nickname, Bode's Galaxy. But his discoveries went unknown by his contemporaries. Both galaxies went unobserved for another 5 years until they were independently rediscovered by Pierre Méchain. Charles Messier incorporated Méchain's find into his burgeoning catalog some 19 months later. Bode, Méchain, and Messier missed fainter companions that are found nearby. Two more decades would pass before William Herschel discovered their dim glows, yet both of this month's challenges - NGC 2976 and NGC 3077 -- can be spotted through small backyard telescopes given good skies.

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Cosmic Challenge: Abell 33

Mar 01 2023 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Several of the challenges I have profiled over the years have involved hunting down tiny planetary nebulae. Many planetaries appear very small as seen from Earth, which can make them difficult to tell apart from surrounding stars. This also works in our favor, however, since their small size focuses all of the available light into small discs with high surface brightnesses. Their existence is also accented nicely by using narrowband and oxygen-III filters, which help suppress light pollution. That's why planetary nebulae are far better targets for urban observers than some other types of deep-sky objects.

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Cosmic Challenge: Palomar 2

Feb 01 2023 07:02 AM | PhilH in Phil Harrington's Cosmic Challenge

Most globular clusters associated with the Milky Way are positioned around the galactic nucleus, and so are referred to as "inner-halo globulars." There is a second family, however, whose members lie far beyond the Galaxy's center and so are known as "outer-halo globulars." Of all the outer-halo globulars known, Palomar 2 is the most extreme, located almost directly opposite the Galactic center in Sagittarius, separated by 85,400 light years.

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Cosmic Challenge: IC 418

Jan 01 2023 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

If you have ever glanced at a compendium of images taken with the Hubble Space Telescope, then chances are you have seen this next challenge. You may not know it by its catalog number, IC 418, but instead may recognize it by its nickname, the Spirograph Nebula. That nickname came about because the Hubble images show an amazingly complex cloud of entangled filaments that create a strange, oval cloud that looks like it could have been drawn using a child's Spirograph toy. Remember those? You would trace intertwining arcs by rolling a color pen in a circle along the inside or outside of another circle.

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Cosmic Challenge: WLM and WLM-1

Dec 01 2022 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

If you thought last month's challenge, IC 1613, was just too easy, try your luck with another member of the Local Group that is also within Cetus.

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Cosmic Challenge: IC 1613

Nov 01 2022 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

The Local Group of galaxies includes three large spiral galaxies – the Milky Way, the Andromeda Galaxy, and the Triangulum Spiral – and dozens of smaller systems. Two of the toughest to see are found in the constellation Cetus and make up this two-month challenge. We begin with IC 1613, discovered in 1906 by German astronomer Max Wolf on photographs taken with the Bruce 16-inch (41-cm) refractor at the Astrophysical Observatory in Heidelberg.

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Cosmic Challenge: NGC 7537 and NGC 7541

Oct 01 2022 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

NGC 7537 and NGC 7541 are two of the more visually interesting galaxies that hide among the faint stars of Pisces, the Fishes. Only 3 arcminutes separate these nearly edge-on spirals, creating an attractive pair of faint fuzzies that float in a field of dim stars.

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Cosmic Challenge: IC 5217, the Little Saturn Nebula

Sep 01 2022 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

As we transition from summer to autumn, let's try our luck with a taxing planetary nebula in an equally taxing constellation. IC 5217 lies among the faint stars of Lacerta the Lizard. Locating the nebula is a big part of the challenge because of its dim surroundings.

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Cosmic Challenge: Great Dark Horse Nebula

Aug 01 2022 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Last month's challenge, to visually spot Abell Galaxy Cluster 2065, could have been subtitled "Go Big or Go Home." That challenge was tough in even that largest amateur telescopes. The good news is that this month's challenge turns the tables. All you need are your eyes. And decent skies.

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Cosmic Challenge: Abell Galaxy Cluster 2065

Jul 01 2022 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

This month, our telescopes will transport us across an incredible 1.2 billion light years (some sources quote 1.5 billion) to Abell Galaxy Cluster (AGC) 2065. More than 400 galaxies are huddled within AGC 2065, but because of that incomprehensible distance, the light from these massive collections of stars has dwindled to nothing more than the faintest whisper. Seeing even the slightest hint of AGC 2065 takes more than just aperture; it also takes supremely dark skies, a trained eye, and an accurate chart of the region.

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Cosmic Challenge: Izar [Epsilon (ε) Boötis]

Jun 01 2022 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Finding this month's challenge object is no challenge at all unless you are trying to starhop to it from the inner city. That can be tough, but for everyone else, Izar (Epsilon [ε] Boötis) is visible easily by eye to the northeast of brilliant Arcturus (Alpha [α] Boötis) as one of six stars that make up the constellation's distinctive kite shape. Swing your telescope its way and it still looks like a single star, as it does to the naked eye. So, what's the attraction?

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Cosmic Challenge: Quasar 3C 273

May 01 2022 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Whenever my neighbor (I'll call him "Joe") sees me at one of my telescopes, he'll come over and ask "so, how far can you see with that thing?" Every time! You've also probably met someone like Joe. Well, unless you have a double-digit telescope, your answer should probably be "2.4 billion light years."

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Cosmic Challenge: Polarissima

Apr 01 2022 05:00 AM | PhilH in Phil Harrington's Cosmic Challenge

In astronomy, as in real estate, we have the Three Ls: location, location, location. NGC 3172 is a challenge for all seasons -- literally -- as its location keeps it above the horizon throughout the year no matter what time of night you are looking. That's because NGC 3172 lies within 1° of the North Celestial Pole, closer than any other NGC object.

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Cosmic Challenge: Beehive Galaxies

Mar 01 2022 07:00 AM | PhilH in Phil Harrington's Cosmic Challenge

Hidden among the stars of M44 are no fewer than eight distant galaxies. Until 1987, most of us knew nothing of them. That was the year when the Uranometria 2000.0 star atlas was published. It showed the sky to a depth never before captured in a convenient star atlas format, and immediately shed light on thousands of objects that no amateurs, except possibly for a few extreme deep-sky hunters, even knew existed.

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