Skywatch: Constant Capella

Four out of the five brightest stars we can see are now readily visible in the early evening celestial dome Of syllabus the sun is our brightest and closest star Once the sun has decisively set this time of year the brightest star is Arcturus lighting up the southern sky and next in line is Vega showing off its brilliance in the high eastern sky Capella is the fifth-brightest star we can see from our planet Look for it as soon as you can in the low northwestern sky poking out of the evening twilight Don t wait too long to look for Capella though because it slips below the horizon shortly after p m Even though it s only fifth place in stellar brightness Capella s claim to fame is that it s the brightest nighttime star that we see greater part often in our northern hemisphere Capella can make that claim because it s the nearest brightest star to Polaris the North Star Polaris marks the position of the north celestial pole Every celestial object we see in the sky day or night whether it s the sun the moon planets or stars all appear to rotate around the North Star Polaris once every hours Polaris is the lynchpin sorry of the sky because it shines directly above the Earth s terrestrial North Pole Mike Lynch If we lived at the North Pole the North Star would be directly overhead and everything in the celestial dome would pivot around the overhead North Star every hours Around here we live about halfway between the North Pole and the Earth s equator so in our sky Polaris is permanently fixed about halfway between the northern horizon and the overhead zenith Stars close to Polaris in the sky like those that make up the Big and Little Dippers and the W-shaped constellation Cassiopeia are so close to the north celestial pole that they re inevitably above the horizon moving in a tight circle around the North Star They are called circumpolar stars and we see them night after night Capella is not quite close enough to Polaris to be considered a circumpolar star but it s close Because of its northward position Capella can be seen in our evening skies from late August to mid-June Throughout the year it never goes an entire night without making at least a brief appearance Astronomically Capella is around light-years away with just one light-year equaling nearly trillion miles While it looks like one giant star it s authentically made up of four stars two binary systems of stars all revolving around each other In each of the binary pairs one of the stars is a huge giant way larger and more massive than our sun and the smaller star is considered a red dwarf way smaller than our sun According to Greek mythology Capella is known as the goat star That s because it s the brightest star in the constellation Auriga the Charioteer The constellation Auriga basically resembles a lopsided pentagon that s supposed to be a retired chariot driver turned goat farmer with a mama goat on his shoulder and baby goats in the crook of his elbow How you get all of that out of a lopsided pentagon is beyond me There must have been quite a party when that constellation was conjured up Capella is supposed to mark the position where the mama goat is sitting on the chariot driver s shoulder and that s why it s known as the goat star Unfortunately all we can see right now of the constellation Auriga in the early evening is Capella By early August though the lopsided pentagon will be available for very early morning viewing in the pre-twilight northeast sky Until then all we have is Capella or what I like to call the Old Faithful of nighttime stars Mike Lynch is an amateur astronomer and retired broadcast meteorologist for WCCO Radio in Minneapolis St Paul He is the author of Stars a Month by Month Tour of the Constellations published by Adventure Publications and available at bookstores and adventurepublications net Mike is available for private star parties You can contact him at mikewlynch comcast net Related Articles Skywatch June stargazing the great late show Skywatch High heavenly hair Skywatch Virgo the Virgin a large but faint constellation Skywatch Crowded space Skywatch Dippers and bears flying high