Saturday, September 30, 2017

Bitternut Hickory?

Go outside during nautical twilight in the morning to see the 'winter circle' of stars.  There are three types of twilight - civil, nautical, astronomical - and specific definitions for how far the sun is below the horizon for each of them.  However, the amount of time they last is different depending on the time of year and your location above or below the equator.  Currently nautical twilight here is from around 6 a.m. to 6:30 a.m.  At this time, all but first magnitude stars have faded from view so it's easy to find just the few stars forming a large circle to the south.   Roughly in the middle of the circle is Betelgeuse (the hunter Orion's armpit) and below it three small stars in a row (Orion's belt)  continuing down to the circle is Rigel (Orion's knee).  From there going clockwise around the circle is bright Sirius (the hunter's dog in Canis Major) and Procyon (the hunter's other dog in Canis Minor).  Further up along the circle are two stars somewhat close together - Pollux and Castor (the heads of the Gemini twins).  At the top of the circle is Capella (the goat held by Auriga the Charioteer).  Continuing down along the arc you come to Aldebaran (the left eye of Taurus the Bull).  Just as easy as that you can now locate six constellations.  Amuse and amaze your friends.

1 comment:

Shelby said...

I always loved being up at the farm as a kid and getting these astronomy lessons. Can't say I remembered them all but a few stuck with me. Nice to read about them again. :-)