Bob Moler's Ephemeris Blog

Tuesday, September 13th.  The sun will rise at 7:18.  It’ll be up for 12 hours and 38 minutes, setting at 7:57.   The moon, 1 day past full, will rise at 8:05 this evening.

There is currently a supernova in a galaxy near the handle of the Big Dipper.  The bright moon is interfering with its visibility in telescopes.  It’s in a galaxy called M101 or the Pinwheel galaxy, a difficult to spot galaxy between and above the two end stars of the handle of the Big Dipper.  The galaxy is 21 million light years away, relatively close as galaxies go.  It is being intensely studied because it is of a type, 1a, that is used for distance measurements of far more distance galaxies.  This kind of Supernova is thought to be the destruction of a white dwarf star in a close binary relation with a more massive star and is drawing matter off the larger star.  When the dwarf reaches 1.38 times the sun’s mass…  Kablooey!  Astronomers are trying to see if that’s true for this star.

* Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.