On June 1st, 1975 the first of a number of short programs
of what became to be called Ephemeris
was aired on Interlochen Center for the Arts's radio station
WIAA. I have produced these programs as a volunteer effort, to
help acquaint listeners to the wonders of the night, and sometimes
day sky, and also to force me to keep informed as to ongoing
astronomical events. What was a "little radio station in the
woods" back then has grown significantly. It has expanded
facilities, and a new name: Interlochen Public Radio. It has multiple
transmitters and two program formats. See the
main page for a listing of stations, times and frequencies
Here are answers to some frequently asked questions.
- How did it get started?
I replied to a general solicitation given by host Chris
Dicken for listeners to produce short weekly segments to run on his
noon time program Bach's Lunch. Starting July 1st, 1974 I produced
such a segment called Moler's Universe
that lasted until the late 80's. The station then went to a format
that included going on the air at 6 a.m., and they asked if I could
do a short program to be aired several times in the morning with
sunrise sunset and something about the sky.
Why is the program called Ephemeris?
The program actually had no name for the first 10 years or
so. The favorite name Almanac was already taken. With my love for
cryptic titles, I chose Ephemeris. From the Greek meaning diary, its
current meaning is a collection of tables giving the positions of
the sun, moon and planets at regular intervals during the year. A
secondary meaning of ephemeris is astronomical almanac.
Do you get up and do your program
I couldn't do that, I'm a night person. The programs are
written in batches of ten for two weeks and recorded all at once,
usually on a Monday morning before 6 a.m. Once due to a really bad
snow storm, a program or two were taped over the phone before 6 a.m.
How do you figure out the sunrise and
When the program first started, the sunrise, sunset and
lunar rising or setting times were interpolated from tables in the
Observers Handbook, a
publication of the Royal Canadian Astronomical Society for that
year. Then I used similar, but more extensive tables in the American
Ephemeris and Nautical Almanac. In 1981 the
U.S. Naval Observatory changed the name to the Astronomical
Almanac (and I was free to steal the word
Ephemeris). However in 1980 I was able to program a Texas
Instruments programmable calculator to produce lists of sunrise and
sunset times for the year. It took 8 hours to calculate and print a
years worth of sunrise or sunset times. The tapes produced would be
taped to sheets for each month. The values would be transcribed to a
monthly spread sheet that has the same format as the Ephemeris
Calendar among these web pages. I would calculate the daylight
hours. Twilight times were produced the same way as sunrise and
sunset, 8 hours apiece.
Moonrise and moonset, a more complicated calculation was
still done from tables. About 1982, using a small computer called a
ZX81 I was able to produce automated moonrise and moonset times with
a program written in Basic.
In about 1983 I was able to purchase an MS-DOS computer,
though it wasn't compatible with today's computers. I wrote a
program called Computed Sky, in Basic, which could display the sky
from any location on earth and could print out the ephemeris page as
it is seen today. Shortly afterwards I wrote Planets which I still
used to produce the charts on the Planet Page. Computed Sky has been
replaced in late 1992 by a new program: Looking
Up, written in the C language, a program that
can calculate a monthly ephemeris page in a few seconds. I also use
it to create Ephemeris star charts.
How has the program changed over the
The format has not changed at all, really. Itused to run
from 60 to 75 seconds. Starting January 2007 its cut down to 59
seconds. The first portion of the program, about 15 seconds
was devoted to the ephemeris tabular listing or calendar,
which I plug values into the script. This table I use for the
program is based on the location of my home, half way between
Traverse City and Interlochen. Since I have a low horizon, I can
spot check the times. <Updated
The second part is the topic of the day. On Wednesday this
is devoted to the whereabouts of the bright planets visible to the
unaided eye. In priority, the topics include events of that day or
night, constellations, stars and planets visible in the evening.
Last in priority is generally astronomical news of a non
observational nature. These topics seem to come up more during
programs when the moon is bright, drowning out the constellations.
In September 2000, I began producing Evening Ephemeris for
the new station WICA. At first they replayed the morning
program. However I wanted to keep the program completely
relevant, and talking about the previous sunrise time around sunset
time wasn't too cool. So I tape two sets of programs with
different part ones. Occasionally, when the morning program
covers a daytime event, a completely different evening program is
written. Starting January 1st 2007 the evening programs were
discontinued due to format changes at the stations. <Updated
How do you come up with the topics you talk about?
I started to answer that above. I crank up the old word
processor program and print the air dates in a column. I consult
astronomical sources for events and tag the dates with those topics.
The rest of the open dates get constellations, a star or planet, or
news. As a planning tool the book Astronomical
Tables of the Sun, Moon and Planets by Jean
Meeus is invaluable for wonderful tidbits of information. Did you
know that spring will not begin on March 21st for United States
until the year 2103?
Other sources are The Astronomical
Almanac, Sky &
Telescope magazine and their Weekly
News Bulletins on the Web, JPL's Space
Astronomical Union Circulars, and running the time lapse feature
of my program Looking Up
to view times and appearances of planetary conjunctions, and what
constellation is oriented which way in what part of the sky.
Once the topics are chosen, all I have to do is write them.
I have built up an extensive library of astronomy, constellation
lore and mythology. It takes about an hour to write a week's worth
of programs, about two and a half pages double spaced. Anyway
writer's block is less stressful with a computer with a screen
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