Archive for April 3, 2017

04/03/2017 – Ephemeris – A two bit* Moon today

April 3, 2017 Comments off

Ephemeris for Monday, April 3rd.  The Sun will rise at 7:19.  It’ll be up for 12 hours and 53 minutes, setting at 8:12.  The Moon, at first quarter today, will set at 3:38 tomorrow morning.

The Moon will  be at exactly first quarter at 2:12 this afternoon (18:12 UT).  By this evening for us the terminator line, which is the sunrise line on the Moon as the Moon’s phase waxes will be bowed to the left a bit.  The names of the primary phases of the Moon are a bit odd.  The quarter moons are named for their positions one quarter or 90 degrees from the Sun.  The full moon describes it appearance as fully illuminated.  New moon is odd too.  To the Jews and the Arabs the New moon was the name for the first sighting of the crescent Moon after it disappeared from the morning sky.  Astronomers use that term today for when the Moon is in conjunction with the Sun, day zero of a lunation or lunar month, about a day before its first appearance in the evening.

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

* If “two bit” is foreign to you.  It dates back to US colonial times when the most prevalent coin around was the Spanish Dollar, also known as a piece of eight.  A quarter of that was two bits, 25 cents in modern parlance.  It lives on in the tune and knock sequence “Shave and a haircut, two bits”  or five rapid knocks a pause and two more.  See the movie “Who Framed Roger Rabbit?”.


Thee Moon's Phases

This is the best diagram of the Moon’s phases and how the it appears from the Earth. Credit which I recommend.

However I do not like the label Dark Side.  It is simply the night side.  The Far Side is what many people mistakenly call the dark side, because we can never see it from the Earth.  However the far side sees more sunlight than the near side.  One, it is never darkened by an eclipse of the Moon, because it’s night-time there normally at that time.  Two, at new moon it is fully facing the Sun, and also a quarter of a million miles closer to the Sun than the Earth is.  So how can it be the dark side.  Really.  Come on people.