Tuesday, August 16, 2011

Sagittarius, or the Effort A Culture Must Exert If It Does Not Have Tea

.....One of the best summer constellations is Sagittarius the archer.  Its central figure made of fairly bright stars, and it is filled with deep sky objects, open clusters, globular clusters, and nebulosity.  The only downside to Sagittarius is that it is low in the sky (in the Northern Hemisphere), so Sagittarius is only visible from late July to late September, but when it is visible, Sagittarius is a visual feast.  If you have a dark sky, the summer Milky Way appears to split between Sagittarius and Scorpius (due to a tremendous amount of non-luminous gas and dust between us and the center of the Milky Way).  If you do not have dark skies, this is still a very rich constellation for binoculars, especially in the central figure of the constellation.


.....Let's take a look at that now.  The stick figure above is supposed to represent a centaur holding a bow, prepared to take out Scorpius execution-style.  This obviously didn't work, because Scorpius is still there, and Sagitta (the constellation of the arrow, as opposed to the constellation of the archer) is north of both constellations, having apparently bounced off of the natural armor of Scorpius.

.....Far easier to visualize is a more modern asterism , the Teapot.  Drawn below, the bright stars of Sagittarius' center form an excellent teapot, with stars like Nunki and Ascella as part of the handle, Kaus Borealis as the top of the dome, and Kaus Media, Alnasl, and Kaus Australis as the spout.  This may still involve some scorpion hate, but it strikes me as far more effective to go after a scorpion with boiling liquid than an arrow much smaller than the scorpion.  Plus, really, scorpions?  %#@& those guys.


.....This brings up a couple of additional points.  Sagittarius seems to have a number of named stars, but scores low points for originality.  What's up with that?  As it turns out, "Kaus" is Arabic for "bow", so three of these stars represent the bow.  (In that case, if someone could give me the Arabic word for "teapot", then I could rename seven stars in one fell swoop.)  "Arkab" is Arabic for "hamstring". 

.....As an aside, the US Navy commissioned a cargo vessel named "Arkab", named after the star(s) that conveyed cargo to Pacific bases during World War II, traveling more than 60,000 miles.  Despite Arkab being Beta Sagittarii (implying that at least one of the Arkabs should be the second-brightest star in Sagittarius), the Navy ship is the coolest fact about Arkab.  Arkab, and Rukbat (Alpha Sagittarii) are actually quite dim, nowhere near being the brightest stars.  In many other constellations, the star "Alpha The-What-The-Heck-Ever-i" isn't the brightest, but it is usually close, or part of a clear pattern (as in the Big Dipper). This time it just makes no freaking sense.

.....One the "Binocular View" close-up of the Teapot, a number of Messier Objects are listed.  Even in a pair of binoculars, the globular cluster M22, and the Lagoon Nebula (M8) are obvious, and wonderful targets.

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