Greetings, fellow SkyWatchers! Are you ready for the weekend? Then let’s tackle both fun and serious studies as we take on a bright open star cluster, Herschel 400 objects, lunar subjects, planets, comets and even a galaxy cluster. If you’re ready to learn more about the history behind the observing and have some fun under the stars, then just follow me…
Honor Lyot’s work by studying two open clusters, found about a fist-width north of Xi Puppis. The brighter of the two – M47 (RA 07 36 36 Dec -14 29 00) – is 1,600 light-years away and a glorious object for binoculars. Filled with mixed-magnitude stars that resolve fully to aperture, M47 features the matched-magnitude double star Struve 1211 near its center. For all its bright beauty, this stellar swarm has the most ironic of histories. Probably discovered first by Hodierna but kept secret, it was independently recovered by Charles Messier, but its position was logged incorrectly. Later, it was cataloged by both William and Caroline Herschel. . .and yet again by John Herschel, who said: ‘‘This cluster has not since been observed. It is probably very loose and poor one.’’ Even Dreyer had a hard time nailing it down! Funny, considering it has only been there for 78 million years…
Saturday, February 28, 2009 – If you didn’t notice the beautiful visage of the tender young Moon and Venus last night at sunset, try again tonight. The pair will be even closer! For most observers, Venus will be only slightly more than a degree away from the Moon’s limb. Have you checked Venus’s phase in the telescope lately? Just like our own Moon, the inner planets (Mercury and Venus) have phases. Because they’re inside Earth’s orbital path, we only see a thin crescent when they first emerge from the Sun’s glare, and they become gibbous as they are about to pass behind the Sun from our point of view. That’s also the reason why we only see these two planets either after sunset or before sunrise!
Take a closer look at the slender crescent Moon. It, too, has only just emerged from the Sun’s glare, and now is the time to get a great look at two craters – Langrenus and Vendelinus. If you remember Mare Fecunditatis, you won’t have any trouble spotting Langrenus on its south shore about mid-way along the Moon’s visible limb. It’s a very old crater with an approximate diameter of 132 kilometers, and appears to binoculars as a shallow, bright ring; featuring a central peak. Further south is equally old Vendelinus. Slightly larger and spanning 147 kilometers, it will appear even more shallow – because it is. It lacks a central peak, but telescopes at high power can resolve its few minor interior craters.
Sunday, March 1, 2009 – In 1966, Venera 3 became the first craft to touch another planet when it impacted Venus on this date. Although communications failed before it could transmit data, it was still a milestone achievement. If you’re out at sunset, be sure to have a look at Venus and say “Spaseba!”
Once you’ve viewed Venus, let’s turn our observations toward tonight’s Moon and begin by identifying some prominent lunar craters around Mare Crisium that can be spotted easily with a small telescope. North you’ll spy Cleomides and at the western edge, Proclus. Near the terminator northwest is Macrobius, and southwest is Taruntius. Power up and identify the small wells of Peirce, Picard, and Lick inside the smooth sands of Crisium. Lather, rinse and repeat… The more often you repeat crater names to yourself (and aloud) the greater the chances are that you’ll retain these names in your memory. Now, let the Moon wester and we’ll go again…
Are you ready to practice Steve’s powers of observation? Then begin with Comet Lulin – now speeding in the eastern edge of the dim constellation of Cancer. If you have difficulty finding it, look for the large, backwards question mark of the prominent asterism of Leo. The bright star you see that’s the “period” of the question mark is Regulus – and Comet Lulin is a couple of binocular fields west. Once you’ve spied it, try comparing details to what you may have observed of Lulin’s previous behavior and appearance. Is the comet moving faster than when you first began observing it? It the tail longer? Brighter? What direction does it point in? Has the coma become more diffuse or larger? Does the comet display a nucleus? Is the anti-tail still visible? Asking yourself simple questions like these will help you become a far better observer!
Until next week? Ask for the Moon… But keep on reaching for the stars!
This week’s awesome images are: Bernard Lyot (public image), M47 and NGC 2423 (Credit: Palomar Observatory, courtesy of Caltech), Langrenus and Vendelinus (Credit: Dave Nash), NGC 2506 (credit – Palomar Observatory, courtesy of Caltech), Crisium area (Credit: Greg Konkel), Stephen James O’Meara (Credit: Sky & Telescope), Saturn & Moons (Credit: NASA), George Abell (Credit: American Institute of Physics), Abell 1367 (Credit: Palomar Observatory, courtesy of Caltech). We thank you so much for sharing the history and mystery with us!
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