Sure signs of winter's demise: a thoroughly-thawed, washed, dried and polished Lawnchair, gleaming in the night air as it salutes the Great Hunter, Orion, his upright sword slowly disappearing below the western treetops at sunset. Yes it’s that time of year when blooms of spring delight the cacophony of diurnal observers, while their tranquil counterparts recline in Lawnchair style, quietly rejoicing in the thought of blizzard-free astronomical adventures in nearly tropical climes. A time when going nocturnal doesn’t require four layers of clothing, three pairs of socks, two mugs of coffee and a partridge-feather-filled, pear-shaped, ski parka. Yes, cabin fever has broken in Lawnchair land!
This late night adventure starts just short of midnight. I'd like to direct your attention toward the large house or barn shaped constellation of Ophiuchus on the small finder map. You'll easily find it in the sky above the eastern horizon.
Ophiuchus is as fantastic a section of sky as there is. Home to both the second closest star to Earth Barnard's Star as well as objects in the distant center region of our galaxy. Ophiuchus lays claim to a wealth of the finest star fields in the heavens. Intertwined by large non glowing dark bodies, as the discoverer of Barnard's star once asserted, "The region is fuller of strange and curious things than any other in the heavens".
Barnard's star is an extremely dim, red dwarf star at magnitude 9.53, just to the east (left) of the star known as Cebalrai, which marks the bottom of the left side of the barn's roof. You can find this on the more detailed second map provided. Barnard's Star lies at a little less than 6 light years from Earth. The only closer stars are those of the Alpha Centauri group, of which Proxima is the closest at a distance of around 4.3 light years. The interesting feature of these "close" stars is that they all have large degrees of what is called apparent motion. Barnard's Star also has an incredibly large radial velocity of approximately 140 kilometers per second in approach. By the year 9800, it will make its closest approach to our sun at around three and a half light years away and then slowly, but surely, continue off on its own path. The proper motion of this star will increase to 25.6" per year by that time. Because of their proximity to us, most of the "close" stars exhibit this kind of velocity. Not that it is unusual, as most stars travel at these speeds. But because of these being so close to us makes them that much more noticeable. Barnard's Star is, if not the fastest, one of the fastest moving (proper motion) stars we know of.
Speaking of strange sights within Ophiuchus, the Pipe Nebula, for instance, named obviously for its shape, is but one of numerous dark areas in and outside the borders of Ophiuchus. These opaque areas of dust and gas block the view to the star fields behind them. But infrared detectors, however, can peer beyond them.
Besides the Pipe Nebula, Ophiuchus is home to dozens of Messier objects, mostly star clusters, all of the "excellent" variety. For example, M 10, 12, 14 and 107, along with many New General Catalog objects like NGC 6633, will provide you with plenty of deep sky targets to revel in within the walls of this great celestial barn. With the aid of the accompanying star maps, you should be able to see these and others in a single evening.
Messier discovered and cataloged M-10, 12, 14 and 107 all within a few evenings. In Messier's day, however, it wasn't realized that these were star clusters. In his crude three inch telescope, they looked the same as most of the other objects he cataloged, "no more than nebulous patches of light". So, in essence, Messier never knew what these objects really were. He never saw what the deep sky photos have revealed of these enigmatic objects. To him, these "fuzzies" were in his way and therefore, the reason to catalog them so they wouldn't be mistaken for the comets he was hunting for.
M 10 is a slightly larger and more loosely compacted cluster, near to M 12, another very nice cluster. Both are accessible with binoculars. A telescope of some strength will be needed, however, to resolve any of these into the myriad stars they are composed of. In binoculars, expect to see what Messier saw some nebulous knots of light. M 12 is the dimmer but larger of the two. M 14 on the other hand, over in a rather sparse section of the constellation on the left side of the barn, is a more difficult target for binoculars or a small scope. It'll take a large instrument to barely get a hint of its almost dust like inhabitants. In long exposure photographs it is, as many other fine globulars, simply spectacular.
Lastly, M 107, also listed as NGC 6171, is one of those additional Messier objects added to the list by Helen Sawyer Hogg. Found floating below the barn's floor, it is a wonderful globular, and like the others, the larger the instrument you use to observe it, the more detail you'll see. There are also several other NGC DSOs throughout Ophiuchus, including both planetary and diffuse nebulae, open clusters and one galaxy, NGC 6384. With dark-adapted eyes under a very dark sky, you should be able to locate many of them. Use the accompanying maps as a starting point.
As mentioned earlier, in addition of these wonderful jewels in Ophiuchus, the area is filled with the thick star fields of the Milky-way. With some of the best examples of dark nebulae, unmatched anywhere else, Ophiuchus is indeed a Lawnchair Happy Hunting Ground. Take your time and enjoy this section of the sky. You won't be disappointed.
Anyone who's ever read my summer columns knows of my love for this particular constellation, specifically its primary attraction, the Great Cluster M 13. Whenever anyone visits Casa Lawnchair, especially when the night sky is clear and the moon is absent, eventually become accustomed to the magic carpet ride that is “Big Red” (Coulter 13.1 inch reflecting telescope the light bucket). Introduced to the sights that make the trip a truly special, though perhaps unusual happening.
Generally, Big Red hibernates throughout winter, though on special occasions, a new comet or something of that nature will awaken it and, after a little shoveling, it "sees" the light of night. In summer, however, it lives near the door and, on most clear nights focuses on the myriad and wonderful "fuzzies" that float across the skies above the Lawnchair's backyard.
With guests in tow, Big Red and I often lead the way on a tour of all my favorites, M 13 included. And to date, after beaucoup years of indoctrinating these not just soon to be, but hooked, lined, sunken and now lifelong enthusiasts, I've never had anyone leave before seeing each and every sight on the tour. There is truly something about seeing these things in person that I’d submit logs subconsciously as tantamount to one or any of life’s most memorable experiences. It is often the first realization of how expansive the universe is. I’ve seen it be life changing, the light going on.
Well I can wholeheartedly say that Hercules is one of those areas where once viewed, uninitiated stargazers are "locked in" for life. Directly over head throughout most of the summer, Hercules' box-like structure sort of looks like a bow tie, though, it is supposed to represent another of the man like pictures, similar to Orion and Gemini. On the right side of what you might call the upper box of this constellation, is what has been described as the most spectacular globular cluster in the sky. M 13 was described by Charles Messier as a "round nebula containing no stars." Of course this was directly related to the crudeness of his instruments. Today's amateur grade telescopes resolve this cluster easily into hundreds of thousands of stars. In the case of the Great Cluster there are actually an estimated one million stars crunched into the space of what looks like a golf ball in a wide-angle lens. Even after decades of seeing and staring, M-13 still fascinates me like very few other deep sky objects ever have.
Though stars within a globular cluster look as though they are jam packed, it is only an illusion. Considering the immense distance to the clusters, and subsequently, their actual dimensions, what in a view from our perspective looks like stars on top of each other, in reality are stars separated by light-years. Robert Burnham described it best when he wrote, and I'm paraphrasing here, "...imagine a spherically shaped 300 mile area containing a million grains of sand (.03 inches in diameter) representing the million stars in a globular cluster. To be accurate, each grain of sand would be separated by a minimum of 3 miles. So, although the stars of these clusters look quite crowded, they are in fact quite alone in the cold, dark and, apparently infinite volume of what we call space. One neat thought I've had often is to imagine living on a planet orbiting a star that in turn resides in or near the outskirts of such a conglomeration of suns. Within the cluster, you'd never see night. No matter where you looked, you'd see suns. Both large and small suns would fill your skies and you'd never know what night was. You'd never realize that there is a galaxy out there and that your suns are only the smallest part of it. This cluster would be your entire universe. For as far as you could see, great balls of fire!
In addition to M 13, Hercules is home to several double stars and variables. There is another Messier object, which perhaps overshadowed by the "Great Cluster", is still a magnificent sight regardless. M 92 is also a globular and easily viewed as a fuzzy star in binoculars. In small telescopes, you may see it resolved slightly. In larger instruments it is quite appealing. It lies up over the main box area of Hercules, where you could imagine his head would be.
Always a great start to summer stargazing, the warming temperatures of May make it an easy adventure out into the night skies. There really are so many sights to behold that not sharing the experience would be a sin. Don't be a sinner!
The Lawnchair Astronomer
Gerry Descoteaux is the author of “The Lawnchair Astronomer,” a Dell Trades paperback. He has been writing about astronomy for more than 25 years. He also played an integral role in the development of America Online’s pioneering distance education program known as AOL’s Online Campus and served as Professor of Astronomy there for 10 years. He can be reached at TheStarMan@thelawnchairastronomer.com.
Notes From the Lawnchair