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.

I started with another weekly program (Moler’s Universe) on IPR 11 months earlier in July, 1974. Celebrating 50 years producing programs for IPR!

Click on the above link for live streaming audio from IPR. Or download the Interlochen Public Radio app from the Apple App Store or Google Play.

Bob Moler's Ephemeris Blog contains scripts and illustrations for 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 in person or via Zoom.


That being said, 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 & 8:19 a.m. - News stations

7 a.m.- Classical stations

The Stations of Interlochen Public Radio


WIAA 88.7 FM Caberfae

W234BU 94.7 FM Traverse City

WIAB 88.5 FM Mackinaw City


WICA 91.5, FM Traverse City

WLNM 89.7 FM Manistee, Ludington

WHBP 90.1 FM Harbor Springs, Petoskey

Note that scripts for the programs plus illustrations and additional information are part of my Ephemeris blog, which can be clicked on above.

Observing Weather in Northwestern Lower Michigan

Clear Sky Chart from Attilla Danko
NWS Traverse City Forecast.
Gaylord, MI Weather Radar.
Canadian based Infrared Satellite (GOES-East data) Michigan shows best in the Eastern Canada view
GOES-East - Sector Views: Great Lakes - GeoColor

Articles of general astronomical interest from my blog

July 2024

Interested in learning more about astronomy or the night sky? 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 scripts, most with illustrations and additional information.

I dug through the IPR web archives and found these:

Bob Moler looks back at 40 years of 'Ephemeris'

I’m interviewed about all things astronomical prior to the August 21, 2017 eclipse. Photo, text, and audio.


Extra! My report on the Great American Eclipse of August 21, 2017, with added animated GIF of the sky at the totally eclipsed Sun, watching the shadow pass over.

Planetary Highlights for July 2024 (ET)

    Date      Time    Event

Jul  1  Mo            Venus: 7.4° E
     1  Mo   2:27 pm  Moon-Mars: 4.2° S
     2  Tu  11:31 am  Moon-Pleiades:  .3° N
     4  Th   8:08 pm  Moon North Dec.: 28.4° N
     5  Fr   1:59 am  Aphelion: 1.0167 AU
     5  Fr   6:57 pm  New Moon
     6  Sa   5:12 pm  Mercury-Beehive:  .1° S
     7  Su  12:04 pm  Moon-Beehive: 3.3° S
     7  Su   2:33 pm  Moon-Mercury: 3.5° S
     8  Mo   4:14 am  Jupiter-Aldebaran: 4.8° N
    12  Fr   4:12 am  Moon Apogee: 404400 km
    12  Fr   6:27 pm  Moon Descending Node
    13  Sa   6:49 pm  First Quarter
    13  Sa   9:48 pm  Moon-Spica: 1° S
    17  We   3:37 pm  Moon-Antares:  .2° S
    19  Fr   6:59 am  Moon South Dec.: 28.4° S
    20  Sa   3:35 pm  Mars-Pleiades: 4.8° S
    21  Su   6:17 am  Full Moon
    22  Mo   2:59 am  Mercury Elongation: 26.9° E
    24  We   1:43 am  Moon Perigee: 364900 km
    24  We   4:38 pm  Moon-Saturn:  .4° S
    24  We   9:40 pm  Mercury-Regulus: 2° S
    26  Fr   1:33 am  Moon Ascending Node
    27  Sa   5:44 pm  Delta Aquariid Shower: ZHR = 20
    27  Sa  10:52 pm  Last Quarter
    29  Mo   5:13 pm  Moon-Pleiades:  .1° N
Aug  1  Th            Venus: 15.9° E

Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),with modifications.

If you go to the above site you can print out a list like the above for the entire year or calendar pages for your time zone.

Note that the site is now kept up for archival purposes. Fred Espenak retired from NASA several years ago and has his own site, AstroPixels, which contain much of the same information in a slightly different format: bmanac.html. However, he doesn’t adjust for Daylight Saving Time. To use DST select times from the time zone just east of your time zone.

Looking ahead This Year

T Coronae Borealis is expected to erupt as a Nova

When? Any time now.

High in the sky can be found a small but easily spotted constellation of Corona Borealis, the Northern Crown. It is located near the kite shaped constellation of Boötes, with its bright star Arcturus at the right. The Northern Crown is a three-quarter circle of stars, like a tiara, with a brighter star Alphecca at the bottom. Alphecca in Arabic means “The bright star of the broken ring of stars”, which is an accurate description of it. Check it out now for later this year we expect to have a bright star appear just below it. That star is T Coronae Borealis ( T CrB) a recurrent Nova or exploding star. They occur when a white dwarf star is orbiting with a large red giant star and accumulating gas from that red giant star until the accumulated material explodes. This happens again and again. In this stars case, about every 80 or so years.

Comet Tsuchinshan-ATLAS

What Comet Tsuchinshan-ATLAS might look like at 8 pm, October 14, 2024 if it behaves. Created using Stellarium.

We expect to see a new bright comet in October: C/2023 A3 (Tsuchinshan-ATLAS), otherwise known in this article as A3 for short. It may be the brightest comet to appear in our Northern Michigan skies since Comet Hale-Bopp in 1997, and a good deal brighter that 2020’s Comet NEOWISE. At least we're hoping.

This comet was discovered last January by the station Xi Yi of the Purple Mountain Observatory in China, and a month later by the ATLAS search program in Maui. ATLAS is an acronym for the apocalyptic sounding Asteroid Terrestrial-Impact Last Alert System.

A3 will best be visible from Northern Michigan toward mid-October in the evening, not long after sunset. The comet is expected to reach magnitude 0 at it's closest to the Sun in late September. However we will be seeing it best as it's leaving the vicinity of the Sun. By mid-October its magnitude will have dropped to magnitude 1 which is still pretty bright and it will be moving at a high angle away from the setting Sun, so it will rapidly increase its distance from the Sun and the horizon faster than it fades in the latter part of October. That is, if it behaves itself. Comets are notoriously fickle in their brightness so we won't know until we actually see it how bright it'll be, or how bright or long its tail will be. As of this writing (Mid-December) A3’s brightness is tracking as predicted, at about 16th magnitude.

The illustration above was created using Stellarium for 8 pm on October 14th. I’ll be tracking the comet’s approach here and on my blog (see link above). As of February 1st it’s distance from the Sun is 3.84 AU, about 1.4 AU inside Jupiter’s orbit. 1 AU (Astronomical Unit) is the mean distance between the Earth and the Sun.

Free Software

Stellarium is a fabulous planetarium program with a very realistic sky and simple controls.

They've added some features in the latest version (23.3) and new rendering engine that may not be compatible with older computers without using command line options. See the Stellarium User Guide (pdf) under Command Line Options for what to try. Finally, after 20 years, it’s out of Beta testing.

There’s a web based version of Stellarium. It’s pretty much bare bones, but works much like the computer version. It’s located here: There is also a smart phone and tablet version both free and $.

Cartes du Ciel (Sky Charts) is a great telescope companion. I use it to create finder charts for comets and calendar lists of twilight times for the monthly preview on my blog. I use it for my weekly look at the planet telescopic appearances. It can be downloaded 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. However it has not been updated in a while.

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 because it loads quickly.

Ephemeris - Years on the air: 49 (Since June 1975)

Years on the Internet: 28 (Since September 1995)


Updated: 07/02/24