Applegater
Winter 2012 7
THE STARRY SIDE
Swinging around the pole star
BY GREELEY WELLS
As I look out at the Winter Hexagon
from the roof deck I have just built on
my Ashland home, I realize that this new
view of the sky has pushed me toward new
understandings of celestial mechanics,
which in turn put me in awe and joy. This
roof deck has become a wonderful platform
for seeing even more sky than I am used
to. Although the Ashland horizon is much
lower than my deep-valley view at Carberry
(and although Carberry has a much darker
and crisper sky, which I love and get
much more detail from), the wide open
Ashland experience has literally widened
my northern views immensely, showing me
how everything really is connected to the
pole star and swings around it in a most
peculiar and marvelous way. Looking out
at this celestial dance, I am grateful to J.D.
for asking me to write this column years
ago, and grateful to all of you who read it
and occasionally make comments and ask
questions, which trigger me to get out at
night more often and learn new things.
The Winter Hexagon (see illustration)
is our companion this season: at first
prominently overhead and then in the
west, it slowly falls into the horizon line
as spring approaches, when it sets early
in the evening. So we all have another
opportunity to figure out the hexagon
and enjoy this winter gem. From my new
Ashland vantage point, I’m learning more,
too. (The Winter Hexagon is an asterism,
or a pattern formed out of several stars that
may be from multiple constellations; the
Winter Hexagon is formed of prominent
stars from six different constellations. To
learn more about the other constellations
in the Winter Hexagon, see last season’s
“The Starry Side” column at our website,
where all past issues are available.)
As I write this in December, Vega
is rising in the north-northeast under
Hercules and Draco early in the winter
mornings. That’s one of the three stars of
the Summer Triangle. Even though Vega
is starting to rise now, it won’t be until
springtime—April—when the Summer
Triangle begins to show up. So if you get
up early in the morning this winter and
look east, you can see the future!
Although some things (such as Vega)
are best viewed in early morning hours,
the standard viewing time is around 10
pm when most of us are on our way to
bed, so that’s the time I generally have in
mind when I’m talking about what you
can see. Remember that before that hour,
constellations may not have risen in the
east and will have gotten higher in the
west. After that hour, the opposite is true:
some constellations have risen further in
the east and gotten higher, and some have
gotten lower and may even have set in
the west. Also, as the season progresses,
the constellations rise earlier each day, so
they are all actually creeping westward
each night.
With that in mind, here’s what to
look for in this new season (February-
April). At 10 pm the Big Dipper is rising in
the northeast; parallel to it, Leo the lion is
also rising. Cancer (the beehive) is dim and
hard to see, but it is the next constellation
as you look westward (toward overhead).
The Gemini twins are high just south of
the zenith, the absolute high point of the
sky. Southwest of them is Orion. Sirius (the
Dog Star) is the brightest star in the sky and
is at Orion’s heels farther south, forming
the bottom of the Winter Hexagon. Even
higher over Orion’s head (close to the “top”
of the sky) is the bright star Capella in the
five-sided Auriga, forming the top of the
Winter Hexagon.
As March comes on, this whole scene
shifts westward. Arcturus (follow the arch
of the Big Dipper to find it) brightly shines
in the east in Bootes. Finally, in April
Orion begins to stand up straight on the
northwestern horizon line, and everyone
continues to shift westward in a large arch
that dips in the south and ends in the
northwest. To the north comes Vega of
Lyra fame, reminding us that the Summer
Triangle will soon be visible. In April, the
Dipper is just north of right overhead;
parallel to it is Leo the lion (with Mars
below near Regulus, the bright bottom
lower left of the moon on the 24th.
T h e s e t h re e m o n t h l y “m o o n
moments” are a chance to notice the
change in the moon’s position each night.
You have two relatively fixed points of
reference (the planets). Now hold out your
fist at arm’s length, and you can watch the
moon parade by at about a fist’s distance
each night.
MARS continues to play below Leo
during this whole season. In February it
moves from west to east, then stops and
moves ‘backwards’ (still under Leo) from
east to west. (In Greek the word planets
means wanderers, and that is what they do.
The starry background is quite consistent
compared to them.) Mars is heading west
toward Regulus in March, and by April
is about four degrees from Regulus when
star in Leo) just south of overhead. Look
directly overhead—the zenith—to find
four dim stars in a gentle, wavy line from
east to west (see illustration) that form Leo
Minor. Can you make them out? Are you
starting to see why I say that everything
around us is swinging in a most peculiar
and marvelous way?
it stops again and begins to move east
away from Regulus once more. Go figure!
Mars then begins a fast fade, becoming
dimmer than Arcturus by May 1. This
gives us an opportunity to compare a
star, Regulus, with a planet, Mars, almost
side by side; you’ll notice that the planet
is steady whereas the star flickers. That is
the difference between the “mere” millions
of miles between us and our fellow solar
system planets, and the light years between
us and the stars. Check out Saturn and
Spica for the same effect if you’re up later
in the evening or look later in the season.
SATURN rises each night in the
east in the late evening, and on February
8 stops its slow eastward movement
and begins slowly moving westward
(called “retrograde”) toward the dimmer
star Spica. In April Saturn is visible all
night next to Spica—another star/planet
comparison opportunity.
VENUS is bright in the evening
sky right after sunset, getting brighter
and higher each night, eventually passing
Jupiter who’s descending (see above). On
February 25, the crescent moon is a few
degrees right of Venus. A similar dance
happens at March’s end: on March 26, the
crescent moon is near the left of Venus, and
the Pleiades are above them both. That’s
Aldebaran (in Taurus, that “V” shape) to
the upper left. The continuing sunset dance
with the moon puts Venus at the upper
right of the crescent moon on April 24.
Early in April Venus runs into the sisters,
the Pleiades, and is at its farthest upwards
and away from the sun. After this, Venus
begins descending. Because Venus and
Mercury both orbit very close to the sun,
they appear either in our sunsets or sunrises
when the skies are dark enough for us to
see them.
MERCURY is also in the end-
THE PLANETS
JUPITER is that incredibly bright
star (planet, actually!) that has been up
almost all night for months and is now
high in the southwest at sunset, heading
farther down each evening toward the
horizon and toward Venus, who is rising
to meet it. In all three of our months this
season, Jupiter and the crescent moon
provide a magnificent late-month show
just after sunset.
From February 23-27, there’s a dance:
Jupiter drops each night from above, Venus
rises each night from below, and a tiny
crescent moon way below (see if you can
see it on the 23rd) moves up each night
until it is above both planets and growing
wider by the 27th. So bide your time and
watch the weather if you want to see this
trio after five late-February sunsets in a row.
(To the right of them is the great square of
Pegasus, on its side like a diamond.)
From March 24-27, there’s another
crescent moon dancing, this time with
the Pleiades above it adding to the fun.
On March 25, the crescent moon is even
closer to Jupiter, and Jupiter has moved
below Venus, which is close to the Pleiades.
From April 23-25, Jupiter is setting
in the sunset, with the Pleiades not far
behind, Venus above, and another crescent
moon moves through each night. On the
23rd, the moon is above Jupiter and left
of the Pleiades. Orion is off to the left of
it all, standing upright on the horizon line.
Aldebaran is the star immediately to the
of-February
s h ow, b u t
very low on
the horizon.
Greeley Wells
(Uranus
is there, too,
between Mercury and Venus, but it’s even
dimmer and you’ll need a telescope to see
it.) By March’s end, Mercury has fallen and
disappeared into the sunset glow.
OF SPECIAL NOTE
Moons of this season include the
Wolf, Snow or Hunger Moon (February
7), the Lenten, Sap, Crow or Worm Moon
(March 8), and the Egg, Grass, Easter or
Paschal Moon (April 6, which is also Good
Friday). All occur around the same day of
the month because there is approximately
one full moon per month. (However, since
this is not exact, we get a parade of full-
moon dates over the long term. And this
year, in August, we’ll have a Blue Moon,
an extra full moon in a single month, just
to shake things up!)
Late February is a prime time to look
for a very subtle effect in the night sky.
From one to two hours after sunset on a
moonless night in the western sky, look for
Zodiacal Light in the ecliptic—the band
the planets, sun and moon move in. It’s
a pearly white, subtle, almost-triangular
light that widens at the horizon. Its
meteoric dust lit high in our atmosphere
by sunlight coming from well below the
horizon high in our atmosphere, which
makes it different from “afterglow,” which
is actual sunlight (not reflected sunlight).
So you have to wait till after afterglow to see
Zodiacal light! Good luck—it’s very subtle.
The Lyrid meteors are very favorable
on April 21-22, with no moon at all to
hide them from view. They can be a strong
shower, radiating from between Lyra and
Hercules on the northeastern horizon.
Here are some dates to keep in mind
this season:
2012 is a leap year, so a leap day,
February 29, has been added. Only 97 leap
days are added every 400 years. So it’s rare!
March 11, early Sunday morning,
remember to change the clock forward one
hour for daylight savings time. (Although
it’s been noted that nothing is “saved” so
it’s really “daylight shifting day”!) Then
the sun will no longer be highest at noon,
but at 1 pm. Personally, I think this whole
concept is bogus.
March 20 is the vernal or spring
equinox. March 20 will continue to mark
the equinox until 2044, after which it will
sometimes shift to the 19th. How this kind
of thing works and who figures it all out
has always fascinated and confused me.
There’s a “dreaded” Friday the 13th
in April, so gird up and be brave! There
was one in January too and will be another
in July. There are usually only one or two
a year, so this must be a particularly bad
luck year. Actually (I reveal myself again),
I think this bad luck stuff is bogus, too!
Finally, April 28 is Astronomy
Day, which started in 1973. You may
want to explore www.astroleague.org.
Another good source of information
is Astronomers without Borders,
who created Global Astronomy
Month in 2010: www.gam-awb.org.
I wish you fascinating nights
filled with stars, planets and meteors.
Greeley Wells • 541-840-5700
greeley@greeley.me
