Archive for February 26th, 2012

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The moon, Venus, and Jupiter, as promised

February 26, 2012

A followup from a recent post. Here’s how the celestial trio looked from my driveway last night. Venus is lowest and Jupiter is highest. No scope for this shot, just my old Nikon Coolpix 4500 on a tripod, about a 1 second exposure. The CCD is a little noisy at that length, especially in low light, so the picture is more pixellated than I’d like, but it’ll do.

Here’s a closeup of Venus and the moon, shot through my SV-50 and a 32mm Plossl (7x), unzoomed.

Tonight the moon is up by Jupiter, and even closer to the King of Planets than it was to Venus last night. I got a quick naked-eye look as we were off to dinner tonight, but by the time we were done eating, the clouds had rolled in, the moon was just a bright fuzzy spot in the sky, and the planets were completely obscured. So it goes.

Next month Venus will be even higher in the sky and Jupiter will be a little lower, so the two will be even closer and prettier when the moon visits them next. Even when the moon is elsewhere, the two planets reward study with the naked eye, binoculars, and telescopes. Mars is up in the east right after sunset, as close to Earth as it will get for the next couple of years, and Saturn is rising around midnight for the night-owls. It’s a good time to observe the planets. Even if all you have time for is a naked-eye peek, you can still appreciate that these moving lights in the sky–“planet” is Greek for “wanderer”–are worlds, that we know something about them, and that someday–maybe–we’ll go out there and explore them ourselves.

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Yet another target of opportunity: Deep Sky Companions: Hidden Treasures by Stephen James O’Meara

February 26, 2012

I do have bigger ambitions for this blog than just collecting deals on astronomy gear from around the web, but this one might not be around for long, so here goes.

The short version, if you’re in a hurry: Stephen James O’Meara’s Hidden Treasures, the third volume in his Deep Sky Companions series from Cambridge, usually $46, is currently on closeout for $18.40 at Amazon. As of this writing, there are only seven copies left at the reduced price.

The long version: Stephen James O’Meara is probably the most respected visual observer of astronomical phenomena of anyone alive. His achievements are legendary. As a teenager, he saw and sketched spokes in the rings of Saturn. Professional astronomers dismissed the spokes as an optical illusion, because the differing rotation speeds of the rings would disrupt and smear out any radial linear features. Then the Voyager probes got to Saturn and, lo and behold, the rings did have spokes–probably electrostatically charged dust floating above the rings and rotating at the same speed as the planet. For most of us the planet Uranus is a dim blue-green dot if we manage to track it down at all; O’Meara saw white clouds on Uranus and mapped their progress to make the first-ever determination of the planet’s rotational period, which was unknown at the time as no space probes had yet made it to Uranus. Voyager II later confirmed O’Meara’s estimate. The list goes on–there’s a pretty good mini-biography of O’Meara in Timothy Ferris’s Seeing in the Dark that describes more of his exploits and achievements.

O’Meara might just have the best vision of anyone alive–at least, when his vision has been tested, it has been sharper and more sensitive than that of any other person who has ever been tested. These tests, by the way, have included having O’Meara sketch faint stars and then comparing his sketches to long-exposure photographs taken with giant telescopes; frequently O’Meara has been able to see things at the eyepiece that no one else can confirm, even when he tells them exactly where to look. (That must be frustrating!)

By all accounts, O’Meara is not only a tremendously accomplished observer but also a darned nice guy. In addition to the Deep Sky Companions series and his other books, he has written observing columns for both Sky & Telescope and Astronomy (and probably others I don’t know about), and his writing is always full of wonder at the night sky and encouragement for his readers to get out and see these things for themselves. One might expect the world’s best visual observer to put on airs and tell the rest of us lesser mortals what deep sky objects really look like. But O’Meara takes the opposite course. He always emphasizes that visual observation of the night sky is an intensely personal experience, presents his impressions of deep sky objects as just that, his impressions, and encourages his readers to get outside, see for themselves, and form their own impressions.

The Deep Sky Companions series now includes four books: The Messier Objects (1998, 318 pages), The Caldwell Objects (2003, 500 pages), Hidden Treasures (2007, 602 pages), and The Secret Deep (2011, 498 pages). The Messier and Caldwell volumes cover the 109 objects on each of those lists in detail. The newer volumes also cover 109 deep sky objects apiece, in homage to the Messier and Caldwell lists, but don’t represent formal observing lists. Instead, the objects are chosen by O’Meara to help observers find and explore some of the lesser-known gems of the night sky.

I haven’t yet seen The Secret Deep, but of the first three volumes, each is better than the last. The Messier Objects introduces the basic format for the series: each of the 109 objects in the book is the subject a multi-page essay that includes its observational history, mythological history (if any), current astrophysical understanding, and visual telescopic appearance, plus a black-and-white astrophoto and an eyepiece sketch by O’Meara. I can’t remember if this is true of the Messier volume–I don’t own it but have only borrowed it from the public library–but the later volumes all have star maps that show the location of each object. The Calwell Objects follows the same format, but the essay for each object is longer and more complete and there is a nice series of appendices, including 20 additional objects readers are suggested to track down and a mini-biography of William Herschel. The Messier volume is a fine book on its own terms, but seems almost skimpy in comparison to its longer sequels.

Hidden Treasures is better still. The star charts are larger and more detailed, the essays are longer and more absorbing, and there is more reference material at the back, including a multi-page table that shows the overlap between the objects included in the book and those on several popular deep sky observing lists, like the Saguaro Astronomy Club’s 110 Best of the NGC.  The mini-biography at the back is of Caroline Herschel, whose formidable achievements in astronomy have been overshadowed by those of her brother William and nephew John. Once again there is a list of 20 bonus objects for readers who want to go beyond the 109 objects covered in detail. The book is a beast, 600 pages long and about 4 pounds. The paper is glossy and the reproduction of the photos, drawings, and maps is very good.

One point of particular interest is an introductory essay in which O’Meara explains how he chose the 109 objects to cover in the book. There were three main sources: O’Meara’s own list of personal favorites, objects combed from several popular “best of” observing lists, and–most interestingly to me–historical lists from the 1700s. There weren’t that many deep sky objects known before William Herschel started his all-sky survey in 1782, and all of them are relatively bright and easy to see in small scopes (otherwise they would not have been discovered in the scopes available at the time), so O’Meara included all of them that aren’t on the Messier and Caldwell lists in Hidden Treasures. Therefore, if you have those three books, you have eyepiece descriptions, up-to-date astrophysical data, charts, sketches, and photos for every deep sky object in the northern skies (i.e., above -10 degrees) known before 1782. That’s pretty cool.

One more point of continuity among the books: O’Meara used a 4-inch refractor from the slopes of Kilauea in Hawaii to observe, sketch, and describe the visual appearance of all of the objects in at least the first three books (except for a few Caldwell objects in the deep southern skies). So observations and sketches among books are directly comparable, having been generated by the same person using the same scope under the same conditions.

I find it interesting and encouraging that O’Meara chose a small telescope to make his observations. Now, O’Meara has the best eyesight of anyone ever tested; his scope, a TeleVue Genesis, is one of the finest refractors ever made; and Kilauea has some of the darkest skies left on Earth. Nevertheless, there are hard physical limits to what a 4-inch telescope can show. O’Meara is humble and forthright in reporting his observations, and when he couldn’t see something–a dark lane in a galaxy, known gas filaments in a planetary nebula–he says so. Anyway, if objects are visible and detailed in O’Meara’s Genesis from Kilauea, they should be observable in commonly available 6- to 10-inch scopes in the more average viewing conditions experienced by most amateur astronomers. So the books are not reports of observations impossible for average stargazers, but guidebooks to help average stargazers make exceptional observations.

I’m happy to recommend all of the books in the Deep Sky Companions series (although I haven’t seen The Secret Deep yet, given the quality of the others I’m prepared to recommend it on faith). If you’re interested in the books, getting Hidden Treasures for less than twenty bucks is an opportunity to test the waters without stressing your wallet. It’s an engaging read on a cloudy night, an enlightening look at how scientific and popular knowledge of celestial objects has changed over the last three centuries, and a genuinely useful guide to finding and observing a host of bright deep sky objects beyond the Messier and Caldwell lists. I ordered a copy when I saw the discounted price, and I’m very, very happy to have it.