Ever wonder about the phases of the Moon? Ever plan a vacation and wonder if it's a good time to bring the telescope along? I was reading in Discover Magazine on the flight to Washington D.C. yesterday and ran into a cool formula for calculating the moon phase for any day between the years 2000-2009. Here is the formula:

Add the digits in the year.

Multiply the sum of the year by eleven.

Add the numeric equivalent for the month (i.e. August = 8).

Add the day.

Subtract 30 from the total until you have a remainder that is less than 30.

The remainder is the number of days since the new moon.

Just remember that a remainder of 7 is the first quarter, 15 is the full moon and 22 is last quarter. So, the moon phase for January 1, 2005 would be calculated this way:

2005 is 2 + 5 = 7

7 X 11 = 77

77 + 1 = 78

78 + 1 = 79

And 30 can be subtracted from 79 twice with a remainder of 19

So, on the evening of the first the of January 2005 the moon will be about half way between full and last quarter and will rise about 4 hours after sunset. Go ahead and take along that telescope for some early evening star gazing. Or whatever.

Now you can throw away that stupid moon phase watch and get one that does something useful. You know, a watch with a barometer, an altimeter and perhaps a compass. A watch worth having. But that's a whole different discussion..........
8:05:44 PM    comment []