Four of the five brightest stars currently seen from Earth are readily visible in the celestial dome.
Of course the sun is our brightest and closest star. Once the sun has finally set these early June evenings, the next brightest “star” to pop out is Jupiter in the south-southwest sky. It doesn’t count, though, because it’s not a star but the largest planet in our solar system. Jupiter is so big that if it were hollow, you could easily fill it up with 1,000 Earths.
Arcturus, the third brightest star seen from Earth, is presently the brightest actual star in the night sky, beaming away in the high southern heavens to the upper left of Jupiter. The next brightest shiner 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 because it slips below the horizon shortly after 11 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 most 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 Polaris once every 24 hours. Polaris is the “lynchpin” (sorry) of the sky because it shines directly above the Earth’s terrestrial North Pole.
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 24 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, such as 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 always 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 northwardly 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.
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 of the constellation Auriga 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!
On Saturday night, the bright planet Jupiter will be in a super tight hug just to the lower right of the waxing gibbous (football-shaped) moon. It should be quite a sight! On Sunday night, the moon will be a little fuller and Jupiter will be just to the left of our lunar neighbor.