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. 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 art of my blog, which can be clicked on above or here.

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

On this site – articles of interest for this month

Beginner's Guide to the Moon

A Hairy Constellation

The Spring Cat - Leo

Looking Out

South Spring Skies

Exploring Spring Deep Sky Objects

The Skies of Spring

May 2022

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 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 May 2022 (ET)

    Date      Time    Event
May  1  Su            Venus: 42.4° W
     1  Su   3:52 pm  Moon Ascending Node
     2  Mo  10:17 am  Moon-Mercury: 2° N
     5  Th   4:57 am  Uranus Conjunction
     5  Th   8:46 am  Moon Apogee: 405300 km
     5  Th  11:55 am  Moon North Dec.: 27° N
     6  Fr   4:00 am  Eta Aquarid Shower: ZHR = 60
     6  Fr   6:56 pm  Moon-Pollux: 2.3° N
     7  Sa   8:23 pm  Moon-Beehive: 4° S
     8  Su   8:21 pm  First Quarter
    15  Su   7:44 pm  Moon Descending Node
    16  Mo  12:11 am  Total Lunar Eclipse
                      See the article below
    16  Mo  12:14 am  Full Flower Moon
    17  Tu  11:23 am  Moon Perigee: 360300 km
    18  We   9:21 pm  Moon South Dec.: 27° S
    21  Sa   3:14 pm  Mercury Inferior Conj.
    22  Su  12:43 am  Moon-Saturn: 4.6° N
    22  Su   2:43 pm  Last Quarter
    24  Tu   3:24 pm  Moon-Mars: 2.9° N
    24  Tu   7:59 pm  Moon-Jupiter: 3.4° N
    26  Th  10:52 pm  Moon-Venus: 0.2° N
    28  Sa  10:33 pm  Moon Ascending Node
    29  Su   4:57 am  Mars-Jupiter: 0.6° N
    30  Mo   7:30 am  New Moon
    31  Tu   1:00 am  Tau Herculid Shower!?
                      See the article below
Jun  1  We            Venus: 36.5° W

All event times are given for UTC-4:00: Eastern Daylight Time

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

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 the same information: However, he doesn’t adjust for Daylight Saving Time.

The May 15/16 Total Eclipse of the Moon

Lunar eclipses or eclipses of the Moon, as these events are also called, only occur at full moon when the Earth's shadow is cast upon the Moon. Unlike a solar eclipse, of which the partial phases are dangerous to gaze upon without special protection, a lunar eclipse is perfectly safe to view throughout.

There are three kinds of lunar eclipses or phases of lunar eclipses: penumbral, partial, and total. A total eclipse passes through all three phases. In the penumbra the Sun's light is increasingly cut off from the outside to the inside of the shadow called the umbra, where all direct sunlight is cut off. Depending on the path of the Moon, it can cut through only the penumbra, in which the eclipse is barely noticeable, a penumbral eclipse. The Moon can just clip the edge of the umbra, to create a partial eclipse. Or the Moon can be immersed completely in the umbra to produce a total eclipse.

Lunar eclipses are easiest to see, because one only has to be on the night side of the Earth to see it. In a solar eclipse, the Moon's shadow is too small to completely cover the Earth, since it's only a quarter the size of the Earth, so one has to be in a band a few thousand miles wide to spot the partial phase and has to be in a very narrow couple hundred mile wide, or less, path to see the brief totality. We'll revisit this in next year in preparation for two country spanning solar eclipses: an annular solar eclipse of October 14, 2023 and the total solar eclipse of April 8, 2024. These two eclipses will appear as partial eclipses here in Michigan.

Eclipses, both lunar and solar occur in seasons nearly 6 months apart, which usually have one of each kind two weeks apart. Occasionally with a central eclipse of one kind to have two of the other type two weeks before and two weeks after. The first eclipse of this eclipse season was a partial solar eclipse visible in the southeastern part of the Pacific Ocean and the southern tip of South America on April 30th.

The reason for eclipse seasons is because the Earth and Moon's orbits are tilted at about a 5° angle, and the point where they cross, 180° apart. Those crossing points, called nodes, are slowly rotating westward, completing a complete rotation in 18.6 years. This gives us two eclipse seasons a year that slowly move earlier in the calendar. It is only when the Sun within about 17.5 degrees from a node do we have a chance for an eclipse, otherwise the Moon is too far north or south. Eclipse seasons last about 35 days.

Shape 1 If you'd like to explore eclipses further, check out this NASA website: If you receive the pdf version of this newsletter and view it rather than print it, the above is an active link.

he eclipse occurs on the 16th for Universal Time, because the eclipse events take place after 8 pm EDT on the 15th.The Moon travels through the Earth's shadow from right to left. What are seen are points of contact with the shadow and mid-eclipse. From Five Millennium Canon of Lunar Eclipses (Espenak & Meeus) NASA, with additions.

Contact times are labeled P1, U1, U2, U3, U4, and P4. P2 and P3 are omitted because they are synonymous with U1 and U4 respectively. Times are EDT unless noted (pm times are the 15th:

P1 – 9:32:07 pm (1:32:07 UT) Enter the penumbra (unseen). By about 9 pm (1:00 UT) the duskiness on the left edge of the moon will start to be noticeable.

U1 – 10:27:53 pm (2:27:53 UT) Enter the umbra (partial eclipse begins).

U2 – 11:29:03 pm (3:29:03 UT) Totality begins.

Mid eclipse 12:11:28.8 am (4:11:28.8 UT)

U3 – 12:53:56 am (4:53:56 UT) Totality ends, egress partial phase begins.

U4 – 1:55:07 am (5:55:07 UT) Partial phase ends. The Moon's upper right edge should appear dusky for the next half hour or so.

P4 – 2:50:48 am (6:50:48 UT) Penumbral phase ends (unseen).

Normally the penumbral effect on the Moon is only noticeable within a half hour or so before and after the partial phase of the eclipse. The duskiness of the penumbral phase of the eclipse can be enhanced by viewing through sunglasses.

During the total phase, light leaks in around the Earth due to the bending of light in the Earth's atmosphere, so the Moon is illuminated by the collective sunrises and sunsets around the globe. This usually gives the Moon a coppery hue, that some are now calling a blood moon. Occasionally, due to volcanic eruptions the Moon can become very dark, almost invisible to the naked eye.

This full moon in May is also called the Flower Moon and for those who care, also a supermoon. It will reach perigee a day and a half later. Throughout the night the Moon will be low in the southeastern part of the sky.

Coming May 31st, The Tau Herculids: Meteor Storm, Meteor Shower, or Nothing!

I almost missed this. While putting together this month's Stellar Sentinel the Extras section turned out to be corrupted. In reconstructing this section, I ran into an article I saved fom It was about a possible intense meteor shower from a comet that began to break up in 1995. The comet was 73P/Schwassmann-Wachmann 3 (SW3). I wrote about the comet and its many pieces that came around in 2006 in the May 2006 issue of the Stellar Sentinel. And I was actually able to spot three of the larger pieces with my telescope.

Its Baaack!

In 2006, 28 fragments were counted. In 2017 there were 2. This approach of this 5.44 year period comet so far shows only one fragment left, but it's early. Its perihelion is in late August, when the main fragment is expected to reach magnitude 12.

The swarm of meteoric fragments is supposed to pass the Earth at about 1 am (5 hr UT) May 31st. That's Memorial Day night. It's also the night after new moon. Despite the name of the shower, the radiant of this meteor shower is expected to be about a third of the way between Arcturus and Cor Caroli in Canes Venatici, near the globular cluster M 3. The information about the peak date and location of the radiant differs from that in the planetarium app Stellarium.

For more information :

International Meteor Organization, pages 9 and 10.

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 (0.22.0) 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.

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:

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. 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.

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.

Years on the air: 46

Years on the Internet: 26


Updated: 04/30/22