Archive
12/20/2012 – Ephemeris – Winter starts tomorrow morning.
Ephemeris for Thursday, December 20th. The sun will rise at 8:15. It’ll be up for 8 hours and 48 minutes, setting at 5:04. The moon, at first quarter today, will set at 1:51 tomorrow morning.
Tomorrow morning at 6:12 a.m. The sun will pass through the point where is appears the farthest south. We call it the winter solstice, or winter sun stand still. If you are measuring the shadow of the sun cast by a stick at noon, tomorrow will be the date of the longest noon time shadow. The ancients, who were not too sure the sun would come back partied big time as the sun stopped the southern progress and began to head back north. This was and is a big festival time featuring lots of lights, be it candles, torches, the burning of the yule log and Christmas lights. For those in the southern hemisphere they are celebrating the summer solstice. In any case our winter is the shortest season.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Noon in Michigan at the winter solstice. Created using Celestia.
To keep the earth large enough, I’ve had to move in to 10 earth radii, so Michigan at the top is a bit closer to the limb than it is to the sun. The vantage point is over the Tropic of Capricorn, 23 1/2 degrees south latitude. The short daylight hours and low sun angle hasn’t caught up to us yet. The coldest days are expected in January.
11/30/2012 – Ephemeris – Previewing December skies
Ephemeris for Friday, November 30th. The sun will rise at 7:58. It’ll be up for 9 hours and 5 minutes, setting at 5:03. The moon, 2 days past full, will rise at 6:58 this evening.
Let’s look at the month of December which starts tomorrow. The hours of daylight will change little except to be darker in the morning and lighter in the evenings. In the Traverse City/Interlochen area sunset will be from 5:03 today, down to 5:02 and then advancing to 5:12 at the end of the month. The earliest sunset will be around the 10th. There is more movement in the sunrise times which will advance from 7:59 this morning to 8:19 on the 31st.Dec 1. Winter will officially arrive at the winter solstice on the 21st at 6:12 a.m. The noontime sun will dip from 23 ½ degrees to a bit less than 22 degrees above the southern horizon on that day. Daylight hours will drop from 9 hours 3 minutes tomorrow to 8:48 on the solstice.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
12/22/11 – Ephemeris – Winter is here!
Thursday, December 22nd. The sun will rise at 8:16. It’ll be up for 8 hours and 48 minutes, setting at 5:05. The moon, 2 days before new, will rise at 7:06 tomorrow morning.
At 12:30 this morning the sun reached its farthest southerly travel and is now slowly beginning to turn northward again. That point was the winter solstice, or to be more general the December solstice, because in the southern hemisphere of the earth summer has arrived, while we star winter. December 21st is the usual day of the solstice, and it will be again next year because next year is the leap year and will set the calendar back to match the seasons. The adding of the extra day every 4 years came under the auspices of Julius Caesar and gave us the Julian calendar. It slightly over corrected the calendar. The latest adjustment was the Gregorian reform that will fix the calendar for the next few millennia.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
12/01/11 – Ephemeris – December preview
Thursday, December 1st. The sun will rise at 7:58. It’ll be up for 9 hours and 4 minutes, setting at 5:03. The moon, 1 day before first quarter, will set at 12:12 tomorrow morning.
December is the month with the shortest daylight hours. Winter will officially arrive at the winter solstice on the 22nd at 12:30 a.m. There will be little movement in the sunset times: In the Traverse City/Interlochen area this will be from 5:03 tonight, down to 5:02 and then advancing to 5:11 at the end of the month. There is more movement in the sunrise times which will advance from 7:58 tomorrow to 8:19 on the 31st. There is also little movement of daylight hours. The noontime sun will dip from 23 ½ degrees to a bit less than 22 degrees above the southern horizon on the 22nd, before ascending to 22 1/3 degrees on New Years Eve. For the straits area the sun will be a degree, or two sun widths lower than these.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Bob Moler's Ephemeris Blog 