Monday, October 26, 2020

The Goat Star in the North

High in the northeast 9:00 p.m, January 28th. Submitted

High in the northeast 9:00 p.m, January 28th. Submitted

by Mike Usher

Tonight we look far into the cold north to find the sixth brightest star in the sky – Capella, the goat star. Auriga, the constellation it belongs to, was often depicted in ancient times as a shepherd in a chariot carrying a goat. The faint stars just to the northeast of Capella are affectionately referred to as “the kids.” Capella is actually four stars in mutual orbit around each other; two are giant stars in a fairly tight orbit around each other and the other two are dim red dwarfs pretty far out. None of this can be seen with the naked eye or binoculars however.

In the 18th century comet hunting was the popular thing to do in astronomy; perhaps ten comets visible to amateurs visit the inner solar system each year. Despite the popular public image of a comet with a tail arcing across the sky, most look like faint foggy patches. Charles Messier was constantly frustrated by his telescope picking up foggy patches that looked like a comet, but turned out not to be. To prevent himself from being fooled constantly he made a list of these fake comets; with commendable simplicity he started with M1 and eventually his list ended with M110. Our optics today are considerably better than his and we have discovered that these Messier objects are some of the great showpieces of the sky and many are more interesting than any comet ever seen.

Some Messier objects are visible to the naked eye, the Great Nebula in Orion (M42) for example. All of them are visible with binoculars, but some are major challenges like M1, the Crab Nebula. Some objects can be resolved by binoculars into their components, and some still look like foggy comets.

Three of these Messier objects appear in Auriga tonight (M36, M37 and M38) and another is nearby in Gemini (M35), all are star clusters. In your binoculars M37 still looks like a hazy patch, while a few stars can be resolved in the others. Not very far off is Praesepe (M44) in Cancer, a beautiful star cluster several times larger than the apparent size of the Moon. For a bit of astronomical trivia, Cancer is the only constellation that has a Messier object in it that is brighter than any of its stars. This speaks more of how terribly dim Cancer is rather than how bright M44 is. See you next time!

Mr. Usher is President of the Everglades Astronomical Society which meets every second Tuesday at 7:00PM at the Norris Center, Cambier Park, Naples.

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