Phil Harrington's Cosmic Challenge Archives

Cosmic Challenge: Zeta (ζ) Cancri

Although it is one of the faintest constellations along the zodiac, Cancer the Crab hosts a variety of targets to test our mettle during the early spring. Spotting M44, the Beehive Cluster, by eye alone may prove very challenging for suburban observers, while the Crab's underappreciated second open cluster, M67, may also reach naked-eye visibility from more rural environs. While the constellation boasts a variety of challenging galaxies, in the test here, we will try our luck with one of the constellation's prettiest binary stars, Zeta (ζ) Cancri.

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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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Cosmic Challenge: Two Pairs

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: The Southern Pinwheel

Have you ever heard of NGC 300, the Southern Pinwheel Galaxy? Were it positioned high in our autumn sky in a prominent constellation, you certainly would have. In fact, NGC 300, an Sc spiral tilted nearly face-on to our view, would be one of the season's showpieces, especially through large backyard telescopes. Because it lies in the far southern sky, nestled among the faint stars of Sculptor, it remains the purview of diehard deep-sky fanatics only.

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Cosmic Challenge: The Orion Galaxy

You've heard of the Andromeda Galaxy and the Orion Nebula, but how about the Orion Galaxy? Probably not. But would you believe the New General Catalog lists 21 galaxies in Orion, and the Index Catalog adds another 9? That's a pretty respectable tally. Of those 30 Orion galaxies, I find this month's challenge particularly intriguing because it lies so close to everyone's favorite winter deep-sky object, M42. Yet, I am sure that very few observers have seen it.

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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: The Eye of Mars

With Mars just having passed opposition on October 13, I thought it might be fun to challenge you to see a specific surface feature on the Red Planet before it slips too far away.

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Cosmic Challenge: The Elephants Trunk

Take a look at just about any star atlas and you will find a huge, irregular cloud of ionized hydrogen suspended to the south of Mu (μ) Cephei, Herschel's Garnet Star. That's IC 1396, one of the largest nebulae in the night sky. Even from a distance of about 2,450 light years, this complex cocktail of bright glowing gas mixed with dark dust clouds spans 3° of our sky. At that distance, 3° translates to a linear diameter of nearly 160 light years, more than three times greater than the Orion Nebula, M42.

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Cosmic Challenge: The Deer Lick Group

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: The Antennae

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: Stephan's Quintet

The canvas on which our picture of the universe is painted relies on the unwavering acceptance of Hubble's Law. Hubble's Law states that a relationship exists between the distance to a galaxy and the speed at which it is receding from us. The farther away a galaxy is, the greater the speed of its recession and farther its spectral lines are shifted toward the red end of the spectrum. For Hubble's Law and the Red Shift Principal to be valid, it must work for not just a few galaxies, but for all. And indeed, it does -- well almost.

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Cosmic Challenge: Spotting Uranus

On March 12, 1781, the solar system was a simple, very well-behaved place that was best summed up with the phrase "what you see is what you get." There were the Sun, the Moon, and the five planets: Mercury, Venus, Mars, Jupiter, and Saturn. Apart from a handful of moons orbiting some of the planets and the occasional faint comet that required a telescope to be seen, the entire contents of the solar system was naked-eye territory.

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Cosmic Challenge: Sirius and the Pup

Ask an amateur astronomer to name binary stars that are difficult to resolve and one of the most common responses will probably be Sirius, in Canis Major. While there are more difficult targets, Sirius is always a perennial favorite. The challenge comes not from the close separation of the two stars in the system, however. Rather, the challenge here is from the extreme difference in the two stars' magnitude.

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Cosmic Challenge: Simeis 147

The year 1054 must have been an active one for stargazers. That was the year that the famous Crab Nebula supernova blasted forth, shining brightly enough for Chinese and Native American skywatchers to note a "new star" blazing near what we now call the tip of one of Taurus the Bull's two horns. The 1054 supernova was so bright that it was visible in broad daylight during the summer of that year and remained visible to the naked eye for nearly a year. Today, we know the fading gaseous remnant of that all-consuming event as the Crab Nebula, M1.

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Cosmic Challenge: Sharpless 2-301

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: Shadow Bands

Enthusiasts think nothing of jetting around the world just to witness the few brief moments of a total solar eclipse. And with good reason, for all who behold the majesty of totality will give impassioned testimony to its unbridled glory. A total solar eclipse is the most beautiful and emotionally charged celestial event of all.

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Cosmic Challenge: Seyfert's Sextet

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: Satellites of Uranus

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

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: Ring Nebula Central Star and Galaxy IC 1296

As we say goodbye to summer and get ready to welcome in autumn, I thought I would offer not one, but two challenges this month to bridge the seasonal change. Both appear right next to each other in our sky but are millions of light years apart. And both require all the aperture you can throw at them to be seen.

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Cosmic Challenge: Quasar 3C 273

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

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: 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: Planetary nebula IC 4732

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: Planetary Nebula GJJC-1

What is your favorite globular cluster? Apart from those two southern hemisphere beauties, Omega (ω) Centauri and 47 Tucanae, my answer has to be M22 in Sagittarius. Admittedly, the star chains and "propeller" formation within M13 in Hercules (profiled in the July 2017 Cosmic Challenge) are visually intriguing. But there is just something about the remarkable richness of M22 and its surrounding star field that calls to me.

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