Archive
01/22/2016 – Ephemeris – Getting sunrise and sunset times for your location
Ephemeris for Friday, January 22nd. The Sun will rise at 8:12. It’ll be up for 9 hours and 24 minutes, setting at 5:36. The Moon, 1 day before full, will set at 7:31 tomorrow morning.
With the bright moon, blocking all but the brightest stars, it’s a good time to do some housekeeping. When I started this program 40 ½ years ago Interlochen Public Radio (IPR) had only one transmitter and a single antenna pattern. It was simply WIAA then. The sunrise and sunset times worked well for that. However since then with transmitters from Manistee to the Straits I cannot hope to cover it all with a single set of times. The differences in the times also 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, or use the email link to request a sunrise, sunset, and Moon calendar for your town. There’s also a link to get sunrise and sunset times for anywhere in the world
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
As an aside. I wrote the program to compute the calendars back in the ’80s. It produces calendars in three formats, of which I still use two: comma separated values, and HTML. The HTML output is what is used for the calendar pages. The comma separated value files are input into a database which is used to create for me the first paragraph of the transcript. For the blog posting I omit “This is Bob Moler with…” as redundant. The program also produces database tables of the planets from which I base the Wednesday planet program rise, set and sometimes transit times.
The actual Ephemeris audio programs are also found on the ephemeris.bjmoler.org under the audio link. A whole week of programs are available.
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
Click on Calendars in the header. and you will get this page.
This is the top of the Mackinaw City calendar where you can select to start at any month.
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.
Bob Moler's Ephemeris Blog 