The sky's brightest star, Sirius, before dawn
4 comments Print Me Email to FriendTonight is Friday, Oct 09 2009
Andy wrote, Early this morning, looking southeast, I saw a beautiful star, bright and multicolored. . .Can you identify it for me?
And Paula wrote, This morning two of us got up early. We found a pulsing star straight down the sky below Orion’s belt. It was pulsing the colors of green, yellow, blue and red like a strobe light. I will search for it every morning as it was so enchanting.
It is enchanting indeed, so much so that – every year, beginning in the fall – we get many, many questions about a multicolored star twinkling in the southeastern to southern sky. This star is Sirius in the constellation Canis Major. It’s rising in the southeast in the hours after midnight now and can be found in the south at dawn.
Just don’t mistake Sirius for Venus, which is brighter. Notice that a line from Orion’s Belt to points to Sirius. Venus is now very low in the west after sunset.
Sirius appears to flash different colors when it’s low in the sky . . . really, all the stars are flashing different colors. That’s because light is composed of all the colors of a rainbow, and the journey through our atmosphere breaks starlight into its component colors. But you don’t notice the colors of the other stars as much, because they’re not as bright as Sirius . . . which is the brightest star visible from anywhere on Earth. Since our atmosphere is causing the light to break into its colors, and since Sirius is only visible low in the sky now (where you are peering at it through a thicker layer of atmosphere than when it’s overhead), the flashing colors of Sirius are very obvious when it is low in the sky.
But when Sirius is higher in the sky – which it is before dawn now. . . or in the evening sky this winter . . . you’ll find that Sirius shines with a steadier, whiter light.
Hi everyone, I am curious to know the name of the really bright star that appears around 3am in a slightly north, easterly direction. It’s closest visible star is below and of an orange appearance. I live on the midnorth coast of Aust. Would appreciate a confirmation,thanks.
Hi Kristin.
That bright “star” that appears slightly north, in an easterly direction, at around 3 a.m. (as seen from the northern coast of Australia) must be the planet Venus, the 3rd brightest celestial object to bedeck the sky, after the sun and moon.
Bruce
I also noticed a star which was the brightest in the sky around 5:30 am in Austin, TX. I was also looking North and East. Would this also be Venus?
Ashley,
Yes, that is the planet Venus in the east around 5:30 a.m. You’ll continue to see this blazing world in the east before sunrise until November 2009.
Please note that this show is for October 9, 2009. At present, Sirius is not visible from our northern temperate latitudes. I give you the link to today’s EarthSky Tonight.
Bruce