Bright bones of the winter sky.
THE CHILL OF WINTER OFTEN sends us indoors from the stars sooner than we'd like. So we're lucky that winter constellations offer more brightness per minute of viewing than those of any other season. When conditions outdoors are so forbidding, it's especially useful to study the framework of the landmark star patterns indoors to help organize your observing time.
What we want to do is look for the bright bones of the winter sky--the skeleton on which all the rest is hung. Our foldout map at right shows the sky situation at mid-evening in December and early evening in January.
The Orion group. Scanning the map, it's clear that the brightest region is around brilliant, geometrical Orion and that star of stars, Sirius. Out under the real sky this fact is even more obvious. Even though Sirius is still rather low in the southeast, Orion and Sirius draw more attention than anything else in the starry sky at map time.
Directly between Orion's golden orange Betelgeuse and white Rigel is his Belt, set with three bluish silver studs. The row of the Belt stars is so eye-catchingly symmetrical that it almost forces us to look in each direction it points: downward nearly toward Sirius and upward nearly toward orange Aldebaran, next to the dim, triangular Hyades star cluster.
Continue the line up past the Hyades and you reach the Pleiades, a naked-eye cluster that really looks clustered. If not temporarily hidden by a branch or chimney, the compact Pleiades are the one stellar sight that can draw even more curiosity than Orion and Sirius. Aldebaran, the Hyades, and Pleiades are all part of Taurus, the Bull.
Beneath Orion's feet is the last constellation of his retinue: Lepus, the Hare. Lepus is unusually realistic as constellations go--a crouching rabbit seen in profile, hiding right under the Hunter's feet while his attention is occupied elsewhere.
The Eastern Spine. Turning due east we encounter Procyon, the Little Dog Star, shining a little higher than Sirius. Above Procyon is Gemini with bright Pollux and Castor on its north end. Higher still is Auriga with bright Capella. The final piece in this vertical column is Perseus at the very top of the sky. Perseus is an outstanding group full of Milky Way richness, even if its brightest two stars are only 2nd magnitude: Mirfak and (most of the time) the famously variable Algol.
The Western Spine. Now turn to face the opposite side of the sky. It's almost as if a backbone of mostly 2nd- and 3rd-magnitude stars hangs from Perseus nearly down to the western horizon. The stars of Andromeda come first as we descend, followed by the Great Square of Pegasus, the neck and head of Pegasus, and finally the horse's orange nose, 2nd-magnitude Enif low in the west.
Two special constellations attract attention on either side of the top of this line. High in the northwest, to the right of Andromeda's feet, is bright Cassiopeia. On the other side is a little bent line of stars that I imagine as looking like a bone you would throw to a dog: the main pattern of Aries, the Ram.
Bones of the low north. Getting low in the northwest is Deneb atop the Northern Cross in Cygnus. In the north, the two dippers' bowls are at a similarly low altitude. The handle of the Little Dipper points up, and the Big Dipper's handle points down.
The other parts of the sky seem boneless, like dim organ cavities. Above the dippers in the north is the dark realm of Camelopardalis and Lynx, two "modern" constellations that date back only a few hundred years. In the south and southwest a vaster void stretches ahead of Orion--he seems destined to walk a dark trail. The only bright objects to relieve this great dark space are visiting Saturn (on the void's northern edge) and two Cetus stars--or possibly three, if the variable Mira has an especially bright maximum this January!
When to use the map
Early December--10 p.m.
Late December--9 p.m.
Early January--8 p.m.
In Other Months:
Early October--3 a.m. *
* Daylight Saving Time
How to use the map
Go out within an hour or so of the time listed at far left. Turn the map around so the edge marked with the direction you're facing (north, southeast, or whatever) is down. The stars above this horizon on the map now match the stars you're facing.
The map's center is overhead. So a star plotted halfway from the edge to the center can be found in the sky about halfway from horizontal to straight up.
For example: Turn the map so its southeast (SE) horizon is down. Nearly halfway from there to the map's center is the constellation Orion. Go outside and look southeast nearly halfway from horizontal to straight up. There's Orion! (Planets are plotted for mid-January).
binocular highlight By Alan M. MacRobert
Clusters in Auriga
THREE FINE OPEN STAR CLUSTERS GLOW IN THE BIG, BRIGHT CONSTELlation Auriga high in the east at map time. You can find M38, M36, and M37 east of center on the map at left. They form a curving line that almost fits into a binocular's field of view.
The brightest is M37 with a total magnitude of 5.6. But M36 and M38 almost match it at magnitudes 6.0 and 6.4, respectively.
All three clusters lie about 4,000 or 4,500 light-years away. They offer beautiful and varied star swarms in a telescope, but because their brightest stars are only 9th magnitude, most binoculars show them as unresolved little cotton puffs.
Another, bigger cluster lies nearby. If you take a jog to the south, M35 in Gemini expands the line to four clusters long. M35 is below the bottom-left corner of the photograph above; it's plotted just off the foot of one of the Gemini twins on the map at left.
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|Title Annotation:||includes related articles on the position of heavenly bodies and the total eclipse of the Sun on February 26, 1998; arrangement of star patterns|
|Publication:||Sky & Telescope|
|Date:||Jan 1, 1998|
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