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

The Great Star Story of Autumn

Autumn Telescopic Wonders

The Celestial River, (The constellation Eridanus)

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

February 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 daily program transcripts, most with illustrations.

Highlights for February 2017 (ET)

    Date    Local   Event
Feb 01  We          Venus: 45.5° E
    02  Th  5:11 am Venus-Mars: 5.4° N
    03  Fr 11:19 pm First Quarter
    05  Su  4:14 pm Moon-Aldebaran: 0.2° S
    06  Mo  8:59 am Moon Perigee: 368800 km
    07  Tu  1:34 pm Moon North Dec.: 18.9° N
    10  Fr  7:33 pm Full Moon
    10  Fr  7:45 pm Penumbral Lunar Eclipse
    11  Sa  9:04 am Moon-Regulus: 0.8° N
    11  Sa  2:49 pm Moon Ascending Node
    15  We  9:55 am Moon-Jupiter: 2.9° S
    18  Sa  2:33 pm Last Quarter
    18  Sa  4:14 pm Moon Apogee: 404400 km
    20  Mo  6:44 pm Moon-Saturn: 3.9° S
    21  Tu  3:50 pm Moon South Dec.: 18.8° S
    26  Su  1:28 pm Moon Descending Node
    26  Su  9:54 am Annular Solar Eclipse - South Atlantic
    26  Su  9:58 am New Moon
Mar 01  We          Venus: 32.5° E

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

Penumbral Lunar Eclipse
February 10, 2017

The Moon at mid-eclipse 7:45 p.m. EST February 10. (00:46 UT February 11) Created usung Cartes du Ciel (Sky Charts).

In the early evening hours of February 10th the Moon will pass through the Earth’s outer or penumbral shadow. It will not get particularly dark since the Moon will still be somewhat illuminated by the Sun. The PC app Cartes du Ciel does a pretty good job of showing it above.

Anything shows two types of shadows in the sunlight. Your shadow appears fuzzy. That fuzziness is your penumbra, where the sunlight is only partially blocked. The dark inner part of your shadow is your umbra.

The eclipse starts at 5:34 p.m. which is before it rises at around 6 p.m. Since the Moon is entering the shadow at a shallow angle it will take 2 hours and 11 minutes to reach tha maximum eclipse. I’m guessing here, but one will probably not notice anything before 7 p.m. To help see the effect better, put on sunglasses. They will reduce the Moon’s glare to help see the darkening effect. The Moon will remain the brightest object in the night sky. Officially the eclipse will end at 9:53 p.m.

Of course the eclipse to really look forward to this year will be the total solar eclipse on August 21st.

Here’s a link to the NASA page for this eclipse.

Binocular Comet 45P/Honda-Mrkos-Pajdusakova

Comet 45P’s track for February. The comet is expected to be about a magnitude brighter than displayed (7th magnitude). Created using Cartes du Ciel (Sky Charts). Click on the chart to enlarge.

Let’s just call it Comet 45P. In the chart above the comet’s position is marked by a comet symbol. The comet’s tail, if visible at all, will actually point to the right along its track. The data for this chart is taken from Seiichi Yoshida’s Weekly Information about Bright Comets.

The GTAS website has a NASA Space Place article about 45P and two other binocular comets to be visible this year and how you can help in observing these comets fro science.

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 , 0.15.0 is the current beta release.

If you have an older computer download 0.12.5, which may work better for you. They've added some features in the latest version (0.15.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. 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 partys as a quick way to see what would be visible.

Years on the air: 41

Years on the Internet: 21


Updated: 02/02/17