This is the companion Web Site of Bob Moler's Ephemeris radio program, which is broadcast Monday Through Friday on Interlochen Public Radio Stations. Interlochen Public Radio serves northwestern lower Michigan. The first Ephemeris program was broadcast June 1, 1975.

Click on the above link for live streaming audio from IPR.

Click here for mp3 audio of the current batch of Ephemeris programs

Bob Moler's Ephemeris Blog contains transcripts and illustrations from the Ephemeris programs. They are generally released at 12:01 a.m. Eastern Time on the program play date.

NASA/JPL Solar System Ambassador


Contact me at the email address at the bottom of this page to discuss star parties and presentations for schools, scout groups, and non-profit organizations.


Opinions expressed on this website are my own and not that of NASA or JPL

Ephemeris Radio Schedule Monday - Friday

Ephemeris air times (ET)

6:19 a.m. - News stations

6:59 a.m.- Classical stations

The Stations of Interlochen Public Radio


WIAA 88.7 FM Interlochen
94.7 FM Traverse City

WIAB 88.5 FM Mackinaw City

WICV 100.9 FM East Jordan, Charlevoix


WICA 91.5, FM Traverse City

WLNM 89.7 FM Manistee

WHBP 90.1 FM Harbor Springs, Petoskey

Observing Weather in Northwestern Lower Michigan

Clear Sky Chart from Attilla Danko
NWS Traverse City Forecast.
Gaylord, MI Weather Radar.
Satellite Infrared Loop.
Canadian based Infrared Satellite (Michigan shows best in the Eastern Canada view)

On this site – articles of interest for this month

Ladies of the Night

Ladies of the Night II

The Celestial River

O'Ryan the Irish Constellation

The Dog Nights of Winter

Auriga the Charioteer

Taurus: Bullish on Winter

Winter Circle

Gemini: The Twins?

VIN: Very Important Nebulae

December 2017

Interested in learning more? If you live in northwestern lower Michigan check out the Grand Traverse Astronomical Society.

More information on visible planetary and other events are available on Bob Moler's Ephemeris Blog the day of the event. The blog contains Monday-Friday program transcripts, most with illustrations.

Extra! My report on the Great American Eclipse.

Highlights for December 2017 (ET)

   Date     Local   Event
Dec 01  Fr          Venus: 9.4° W
    03  Su  8:00 am Moon-Aldebaran: 0.8° S
    03  Su 10:47 am Full Moon
    04  Mo  3:42 am Moon Perigee: 357500 km
    05  Tu  6:43 am Moon North Dec.: 20° N
    07  Th  4:30 am Moon-Beehive: 2.5° N
    07  Th  7:39 pm Moon Ascending Node
    08  Fr  5:25 pm Moon-Regulus: 0.7° S
    10  Su  2:51 am Last Quarter
    12  Tu  8:40 pm Mercury Inferior Conjunction with the Sun
    13  We 11:27 am Moon-Mars: 4.5° S
    14  Th  1:07 am Geminid Meteor Shower: ZHR = 120!
    14  Th  9:26 am Moon-Jupiter: 4.7° S
    18  Mo  1:31 am New Moon
    18  Mo  8:27 am Moon Apogee: 406600 km
    19  Tu  4:31 am Moon South Dec.: 20.1° S
    21  Th 11:29 am Winter Solstice
    21  Th  3:18 pm Saturn Conjunction with the Sun
    22  Fr  5:04 am Moon Descending Node
    22  Fr 10:00 am Ursid Meteor Shower: ZHR = 10
                    Note:  The Ursid radiant is near
                    the Little Dipper’s bowl
    26  Tu  4:20 am First Quarter
    30  Sa  7:25 pm Moon-Aldebaran: 0.7° S Occultation
Jan 01  Mo          Venus: 1.9° W

NASA - SKYCAL - Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA's GSFC) (with occasional annotations)

Occultation of Aldebaran

Map of the area where the occultation of Aldebaran will be visible. Created using Occult 4 from

For Traverse City/Interlochen the occultation will start at 6:17 p.m. EST December 30 and end at 7:16 p.m.

It will vary by a few minutes for northern lower Michigan. Otherwise use a planetarium program like Stellarium to preview the event. However, set the program for topocentric coordinates. In Stellarium that’s in the Configuration window, Tools Tab and check the Topocentric coordinates box. Topocentric coordinates are the apparent positions for your location on the Earth. For Cartes du Ciel (Sky Charts) The setting is under Setup/Solar System. So also make sure your location is correct. The geocentric conjunction of the two bodies will be December 31, 0:49.2 UTC, so it will occur after midnight on the night of December 31st for locations in northern Europe and Asia.

I’ll have more information on December 29th on my blog

Active Planetary Space Missions

We have a new location for information on planetary space missions. It's here at the Planetary Society. The chart is created by Olaf Frohn, and is updated every month.

Free Software

Stellarium is a fabulous planetarium program with a very realistic sky and simple controls. The newest version , 0.16.1 is the current beta release.

If you have an older computer download 0.12.8, which may work better for you. They've added some features in the latest version (0.16.n) and and a new rendering engine that may not be compatible with computers more than a year or two old.

Cartes du Ciel (Sky Charts) is a great telescope companion. Version 4.0 came out in March 2016. You can download it from

Virtual Moon Atlas is a great tool for reference at the telescope or desk.

Celestia is a great 3D simulator of solar system objects and beyond.

Hallo Northern Sky is an interesting planetarium program. It seems not as polished as Stellarium, but has some cool features. I use it when planning star parties as a quick way to see what would be visible.

Years on the air: 42

Years on the Internet: 22


Updated: 12/01/17