Sky and Telescope - January 2016 - 45

OBSERVING

Northern Hemisphere's Sky

Fred Schaaf welcomes your
comments at fschaaf@aol.com.

Fred Schaaf

Many Bright Beginnings
The sky oﬀers a number of choices for marking the start of your year.

Taurus

Pleiades

ζ
α
BOB KING

Are you ready to celebrate a happy New Year? In
today's international secular calendar, the ﬁrst day of the
year is, of course, January 1st.
But this has been far from the case in many individual cultures and times. Let's take a look at a few of these
- they're all based on astronomy and a few on the positions of very speciﬁc stellar objects. Then let's see how,
during a January evening of observing, we can celebrate
several diﬀerent times we might regard as a ﬁtting start
of a celestial calendar or clock.
Welcome to January, the eleventh month. The
ancient Roman calendar began with March. That's why
September through December have the root words for
seven through ten in their names: they were the seventh
through tenth months of the year. (The ﬁfth and sixth
months were Quintilis and Sextilis; they were renamed
to honor Julius Caesar and Augustus Caesar - and
became our July and August.) In England and its American colonies, the year began with March until 1752.
So what - or who - is January named after? The
ancient Roman god Janus, who literally had two faces,
one looking forward and the other backward through the
door. That seems wonderfully appropriate for the start of
a calendar because it's a time when all of us cast a look
back to the old year and forward to the new. But this persumably wasn't what the Romans intended, given that
their January (Januarius) was the 11th month of the year.
A modern astronomical twist is that one of Saturn's
moons, Janus, has a two-part, forward-and-backward
connection not realized when it was named. Janus is
one of two broken halves of an earlier Saturnian moon.
The other "half" is Epimetheus and, amazingly, it trades
places with Janus, switching which moon leads and
which one trails, as they orbit near the rings.
The Sirius-based and Pleiades-based years. Several cultures based their year on positions of nighttime
stellar objects - objects that happen to be splendidly
visible on January evenings. The ancient Egyptians
noted that the heliacal (dawn) rising of Sirius coincided
with the annual summer ﬂooding of the Nile - so this
rising became the marker of the Egyptian New Year. The
Druids chose the mid-autumn acronychal (sunset) rising
of the Pleiades, probably when the year's agriculture
ended, to mark their New Year (a holiday that eventually
transformed into Halloween).

Four beginnings on a winter evening. But we could
pick several sidereal times that occur on January evenings to be our own unoﬃcial start of the starry year.
First, nightfall in early January. Which hour of right
ascension is on or near the meridian? The zero hour.
Last month we looked at this state of the heavens in
the evenings of November and December. M31, the
Andromeda Galaxy, nears the zenith. Orion is just risen
- indeed, my 40°° N version of Skygazer's Almanac indicates that Betelgeuse rises at sunset on December 31st.
But suppose we go out four hours after nightfall.
Now on the meridian is noble Taurus, featuring the
Hyades, Pleiades, Crab Nebula, and more. Regulus has
risen, Deneb is setting. And why is this an appropriate
"starting time" for the heavens? "A" may be the ﬁrst
letter of our alphabet because its original upside-down
form was a little picture of Taurus and his horns - and
something like 4,000 years ago Taurus contained the
vernal equinox and was therefore the ﬁ rst constellation
of the zodiac.
Six hours after nightfall, Leo is fully risen, Pegasus is
setting, but what's on the meridian makes this another
candidate for being our starting-time-of-the-stars hour:
Orion, the brightest constellation.
We ﬁnally reach seven hours after New Year's nightfall - midnight - and what's on the meridian? Marvelously, the brightest star by far, mighty Sirius - making
this another grand stellar beginning. ✦
Sk yandTelescope.com Januar y 2016

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Sky and Telescope - January 2016

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