Orion and Sirius, imaged 2014 March 27 from Paris, Virginia with a Canon EOS Rebel T2i DSLR camera.

The Moon wanes as she moves into the morning sky and the rising springtime constellations.  Last Quarter occurs on the 25th at 9:41 am Eastern Standard Time.  Late-night skywatchers can see Luna approach the bright star Regulus, the heart of Leo, the Lion, after she rises on the evening of the 19th.  Early risers on the morning of the 24th can spot the Moon just north of the bright star Spica in the constellation of Virgo.  

Stargazing at this time of year takes a certain amount of fortitude.  The blasts of arctic air that pour down from the north can make an evening under the stars a test any person’s mettle.  However, the cold air usually means low humidity and no haze, so we often experience nights with the highest sky transparency.  I have found that crisp cold winter nights allow me to see stars that are about a magnitude fainter than those I can see in summer nights.  The trade-off is that I have to bundle up from head to toe to enjoy a modicum of comfort.  Fortunately we have modern materials to insulate us, unlike astronomers from the “classical” era of visual observing.  One of America’s leading astronomers of the day, Edward Emerson Barnard, worked at the Yerkes Observatory in Williams Bay, Wisconsin, spending countless winter nights observing with the great 40-inch refractor located there.  He habitually observed in sub-zero conditions, much to the dismay and discomfort of his night assistants.  A reporter once asked him how astronomers kept warm on long January observing sessions; his answer was “We don’t.”

The bright stars of the boreal winter sky offer little respite from the cold, but their cheerful glow and varied colors make cold weather observing a bit more tolerable.  Foremost among these bright luminaries is Sirius, which trails the distinctive constellation Orion across the sky.  Sirius is the brightest star in the sky, and, as such, has been deeply embedded in human culture since ancient times.  The ancient Egyptians identified the star as Sepet, the soul of the goddess Isis, one of the oldest deities in their pantheon.  The annual rising of Sirius just before the Sun preceded the annual flooding of the Nile, which sustained their civilization for 3000 years.  Although it is often referred to as the “Dog Star” from its association with the constellation Canis Major, the star’s name derives from the ancient Greek word that means “the scorcher”.  Indeed, when the star is near the horizon, atmospheric refraction causes the star to flicker through the colors of the rainbow, giving the impression of a dancing flame.  Sirius owes its brightness to its proximity to the solar system at a distance of just 8.7 light-years.  The star is about 23 times as luminous as the Sun and glows with a distinctive blue tint.  Sirius was one of the first stars to have its motion across the sky measured.  Edmond Halley (of comet fame) discovered its changing position in 1718 by comparing his measurements of the star’s position with those of Ptolemy and Hipparchus.  In the decade between 1834 to 1844 the German astronomer Friederich Bessel noticed irregularities in the star’s proper motion and attributed them to an unseen companion circling the bright star.  The companion, now known as Sirius B or “The Pup”, was discovered on January 31, 1862 by the American telescope maker Alvan Graham Clark while testing an 18.5-inch lens ground and polished by his father.  It was the first white dwarf star to be discovered.

The only bright planet now easily visible in the evening sky is Jupiter, which pops out of the twilight glow in the southwestern sky about 15 to 20 minutes after sunset.  Old Jove only spends an hour in the sky after evening twilight ends, and his proximity to the horizon makes it difficult to see fine details in his turbulent clouds.  

You might be able to glimpse Saturn as twilight deepens, but the ringed planet now sets before the end of twilight.  He is now far too low to observe with a telescope, but you should be able to spot him in binoculars.

Ruddy Mars may be glimpsed in the pre-dawn sky, low in the southeast, but you will likely need binoculars to see him.  Half an hour before sunrise, look to the southeast for the bright glow of Venus if you have a low horizon.  The dazzling planet will become much more prominent as the month ends.

Messier 42, the Great Nebula in Orion, imaged 2021 December 27 from Ocean City, Maryland with an Antares Sentinel 80mm (3-inch) f/6 refractor, iOptron Cube Pro alt-az mount, and a Canon EOS Rebel SL2 DSLR.

The Moon waxes as she arcs through the stars of the Great Winter Circle this week, brightening the long chilly winter nights.  Full Moon occurs on the 17th at 6:48 pm Eastern Standard Time.  January’s Full Moon is popularly known as the Wolf Moon, a name that derives from old European accounts of wolves howling through the long nights.  Other names include the Ice Moon and Moon after Yule.  Look for the Moon to the south of the Pleiades star cluster on the evening of the 12th.  She passes between the “horns” of Taurus, the Bull, on the evening of the 14th before moving through the stars of Gemini to close out the week.

January is the month that features the stars of the Winter Circle as the showcase for nighttime viewing.  Somehow the colder air seems to accentuate the stars’ varied colors.  Despite the strengthening light of the waxing Moon, the collection of bright stars in this part of the sky seems to stand out more clearly than at other times of the year.  I have often marveled at how the stars of winter seem to add a sense of warmth on nights with frigid temperatures while brightening the darkness of the lengthy nights.  Ten of the thirty brightest stars in the entire sky lie within the confines of the Winter Circle asterism.  

I still remember the cold January night when, as a child, I first “discovered” the three “Belt Stars” of Orion.  Although they were not the constellation’s brightest members, their near-perfect spacing and striking blue colors made them easy to spot night after night.  I soon learned to recognize the other constellations in the vicinity, but Orion always stood out.  After my first telescope arrived under the Christmas tree, I spent many cold January nights looking at each of the Hunter’s stars before stumbling on the group known as “The Sword”.  Amid the field of blue stellar beacons was a small knot of stars surrounded by a soft, fuzzy glow.  I had “discovered” the Great Orion Nebula.  Over the years I learned more about Orion’s stars as well as his wonderful non-stellar objects like the Great Nebula.  Even today I spend more time observing Orion than just about any other constellation.

Orion offers observers of any skill level a host of objects to delight the eye.  Even without a telescope, the contrast between the ruddy hue of the star Betelgeuse with the ice-blue tint of Rigel is striking.  Binoculars enhance this contrast and bring out the deeper blue tints of the Belt Stars.  Looking under the belt stars will reveal the gaggle of stars of the Sword, and in the middle you will see the brighter parts of the Great Nebula.  The small fuzzy patch that you see in binoculars becomes exquisitely detailed as you employ telescopes of larger apertures.  Even under bright suburban or moonlit skies the nebula becomes almost three dimensional, its brightly glowing core surrounded by dark whorls of opaque dust and gas.  In its center you will find a tight knot of four stars known as the Trapezium, and these stars are some of the youngest known in the galaxy.  The Great Nebula is a true stellar nursery, and almost all of Orion’s blue stars originated there.  It remains my favorite “deep sky” object in the sky.

The bright planets have now retreated to the early evening and pre-dawn sky.  As evening twilight falls, look to the southwest for bright Jupiter, which should be easy to spot about 20 minutes after sunset.  By 6:00 pm, if you trace a line from Jupiter to the sunset point on the horizon, you should be able to see the paler glow of Saturn about ten degrees above the horizon.  If you scan between Saturn and the horizon, you should be able to spot the somewhat brighter glow of the elusive planet Mercury, which will seem to hang in this part of the sky before beginning a precipitous drop toward the Sun by the end of the week.

If you’re up before dawn look to the southeastern sky as morning twilight begins to brighten the horizon.  You will find the stars of Scorpius becoming prominent, led by the bright red-hued Antares.  Thirteen degrees to the east of the star is another ruddy object, the planet Mars.  Over the course of the week the red planet will about five degrees further eastward from the star.  As twilight becomes brighter, keep an eye on the southeast horizon for the bright glow of Venus.  By 7:00 am she crests the horizon, and by the end of the week you should be able to see her more easily as she climbs away from the Sun’s glare.