01/05/2015 – Ephemeris – Ephemeris’ dirty little secret
Ephemeris for Monday, January 5th. The sun will rise at 8:19. It’ll be up for 8 hours and 56 minutes, setting at 5:16. The moon, 1 day past full, will rise at 6:14 this evening.
With the bright moon, blocking all but the brightest stars, it’s a good time to do some housekeeping. When I started this program 39 ½ years ago IPR had only one transmitter and a single antenna pattern. The sunrise and sunset times worked well for that. However since then with transmitters from Manistee to the Straits I cannot hope to cover all that in a single program. The differences in the times vary with the seasons. To get help on the Internet go to my monthly site ephemeris.bjmoler.org and click on Calendars. There are calendars for Ludington, Cadillac, Interlochen/Traverse City, Petoskey and Mackinaw City. Select a month to view or printout a whole year. Use the email link to request a sunrise, sunset, and Moon calendar for your town.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

Partial image of the January calendar for Mackinaw City. The last column illum Fractn is the moon’s illuminated fraction. It is set for 24h UT, which is early evening on the date listed.
Interesting note: You can draw a straight line through Ludington, Interlochen/Traverse City, Petoskey and Mackinaw City. The angle with that line and the meridian is about 23 1/2 degrees. The same as the tilt of the Earth’s axis. Therefore near the winter solstice the sunrise times are nearly the same, but the sunset times can differ greatly. Conversely at the summer solstice the sunset times are nearly the same, but the sunrise times are the most divergent.

