Phil Harrington's Cosmic Challenge Archives

Cosmic Challenge: Galaxy UGC 2838

The Pleiades is one of everyone's favorite winter sights. You and I probably look up at that tiny pot of stellar jewels every winter night we head out, just as we have ever since we first became fascinated with the night sky. It’s a seasonal rite. But did you know there was a small galaxy lurking behind the Pleiades? Not many people do. Its faint disk was never seen by the Herschels or known to John Dreyer when he assembled the New General Catalog and supplemental Index Catalogs.

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Cosmic Challenge: Palomar 13 and Friends

Pegasus is best known to deep-sky observers as a breeding ground for faint galaxies, with more than 100 faint NGC galaxies littering this winged steed. Floating seemingly out of place among those systems is the globular cluster M15, one of the season's finest targets. Did you know that there is a second globular within Pegasus lying just within the grasp of your 10-inch telescope? That little known target is Palomar 13, one of those nasty globulars discovered by Abell and company while surveying the Palomar Observatory Sky Survey half a century ago.

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Cosmic Challenge: IC 5067 and IC 5070 (Pelican Nebula)

My September 2018 Cosmic Challenge dared you to see the North America Nebula without optical aid. How did you do? If you didn’t see it back then, can you now? If you passed that trial, then pick up your binoculars and see how you do with this month’s test. The North America Nebula is easy to see compared to spotting this month's challenge, the Pelican Nebula by binoculars.

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Cosmic Challenge: IC 4997

This month’s challenge, the planetary nebula IC 4997 lies within the borders of Sagitta, and is surprisingly bright, but extremely small. That combination makes this a great object for everyone, whether you are observing under the veil of light pollution or from a dark, rural location. Its intensity should shine through all but the most extreme situations.

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Cosmic Challenge: Draconian Doubles

The constellation of Draco the Dragon winds its way through our northern August sky, and while most of its stars are fainter than 3rd magnitude, it holds some fun resolution challenges for binoculars. Here are three of my favorites.

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Cosmic Challenge: NGC 6453

NGC 6453 shines at 10th magnitude and measures nearly 8' across. Were it alone in the sky, it would be a fairly routine catch in 8-inch (20-cm) and larger apertures. But NGC 6453 is not isolated by any means; instead, it is immersed in a heavily packed field of stars. Spotting it can be literally like finding a needle in a haystack!

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Cosmic Challenge: Hortensius and Milichius Dome Fields

Thanks to the lunar samples bright back by Armstrong, Aldrin, Collins, and the other Apollo astronauts, it is well established that the vast majority of craters are impact craters formed when leftover debris from the formation of the solar system slammed into the Moon. But if we look carefully, scattered among all of those impact scars is direct evidence that the early Moon was also a hotbed of volcanic activity. Some of the most intriguing evidence of that activity is the so-called lunar domes.

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Cosmic Challenge: Palomar 4

When you think of deep-sky objects in Ursa Major, you probably don't think of globular clusters. Galaxies, sure! Planetary nebulae? There's the Owl Nebula. But globular clusters? Probably not.

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Cosmic Challenge: NGC 4361

Corvus, the celestial crow, flies low in the spring sky as viewed from the northern hemisphere. Located between the constellations Virgo and Hydra, it is easily identifiable by its compact shape resembling a perched bird. The crow carries with it but one notable deep-sky object for backyard telescopes. Planetary nebula NGC 4361 is almost perfectly centered within Corvus's trapezoidal body.

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Cosmic Challenge: NGC 2403

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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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