Some Light Science Reading. The Constellations: Capricornus

As first appeared in the July 2009 edition of the Syracuse Astronomical Society newsletter The Astronomical Chronicle (PDF).

Constellation Map generated with Starry Night Pro 6.

In all my many years on this planet, I’ve met several people who were born between mid-January and mid-February, but I’ve never met anyone who described themselves as a Capricorn (of course, I don’t walk around calling myself a Cancer, either).  Capricornus is the second dimmest Constellation in the Zodiac (after, you guessed it, Cancer) and, generally, there is precious little within it that an amateur astronomer would find of any interest.

“You’re not selling me on this article,” you’re saying.

During August, Capricornus is playing host to a special object in the Night Sky.  Jupiter, in its saturnian motion along the ecliptic, is presently (as of this writing) just at the fishy tail of one of the Constellations known for its crazy genes (with its neighbor, Sagittarius, discussed in last month’s installment).  Despite the seemingly small distance it has to travel before hitting the Western boundary of the tail (on the left-hand side of the image above), Jupiter will remain in Capricornus until January of 2010 and, for those of us viewing at Darling Hill, it will remain visible in the early evening sky until mid-November (perhaps for our last official viewing session of 2009).

Your scope or big binoculars will already be pointed at Capricornus for any Jupiter viewing for the near future, so you might as well give your finder scope a bit more of a workout and try to find the few, but not insignificant, objects in this mild-mannered Constellation.  The only Messier Object, M30, is at lower left, a globular cluster roughly 26,000 light years from Earth.  Just to the lower-right of Phi Capricornus (the star at the middle of the curled tail in the image above) is the yellow dwarf HD202206, one of the increasingly large family of stars known to host an extrasolar planet.  Alpha Capri (upper right) is an optical binary that may be separable in your eyepiece, while Beta Capri is a visual binary with a nice orange/blue color contrast.  Palomar 12 is a star cluster dim enough that reports at cloudynights.com indicate something bigger than a 13″ scope is required to see it.  If you can see the triangle of stars, you’re looking right at this small object.  While several galaxies lie in this Constellation, their surface brightness is low enough that you’ll need time or long exposures to find them.

And for those of you with an interest in the history of this and other far-out Constellations, check out the PDF article linked HERE.

You dig?
Damian

en.wikipedia.org/wiki/Capricorn_(astrology)
en.wikipedia.org/wiki/Cancer_(astrology)
en.wikipedia.org/wiki/Capricornus
en.wikipedia.org/wiki/Zodiac
en.wikipedia.org/wiki/Ecliptic
en.wikipedia.org/wiki/Sagittarius_(constellation)
en.wikipedia.org/wiki/Messier_Object
en.wikipedia.org/wiki/Messier_30
en.wikipedia.org/wiki/HD_202206
www.cloudynights.com/item.php?item_id=1700
articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?db_key=AST…=Send+PDF&filetype=.pdf

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