Tuesday, September 15, 2009

Did you see the crescent moon and Sirius this morning?

Did you see the crescent moon this morning just before sunrise?
  1. crescent moon, on its back at nearly zero degrees tilt
  2. Orion, higher up and to the right, similar to the photo below
  3. Sirius the Dog Star, brightest star in the sky, between the crescent moon and Orion and slightly below the line between them.
And Orion is a good constellation to know, because it is
  1. beautiful and
  2. easy to spot with the belt of three bright stars, almost as easy as the Big Dipper


Here is a lovely photo from AstoBob in Minnesota, showing late August sunrise, with Orion just before dawn. If only we had clear skies like that here in Florida!!!



We call the hottest days of summer the "dog days" because the Dog Star Sirius is right behind the sun, rising with the sun but invisible to us, from mid-July and continuing for a few weeks. Those are some hot weeks, though not coinciding with the peak of hurricane season. DANG!

It is interesting to work out the three-dimensional motion of this Earth-Moon-Sun-constellation system to see why the moon lies on its back. Baseline reason: we are right up close to the autumnal equinox.

Sunup time today