Contemplate constellations and pick out planets, even as January’s temperatures chill.
Jupiter opens January’s night sky festivities at dusk well above the horizon, snuggled between the constellations Pisces and
Aquarius in the south-southwest. You’ll recognize the king of the planets by its brightness, since it loiters at negative second magnitude, bright enough to see from urban skies.
By the middle of the month, Jupiter descends to the horizon about 10:30 p.m., and it ducks out around 9:40 p.m. at month’s end.
Before Saturn rises near the midnight hour, enjoy the parade of constellations on these crisp winter nights. They seem to follow Jupiter like a planetary pied piper. Orion dominates the season’s heavens. Along the ecliptic, Orion is followed by Gemini,
Cancer and Leo. Orion the Hunter makes its presence known. If you look toward the south about 9 p.m., Orion is the huge constellation in the south with an “H” shape. The right shoulder belongs to the star Betelgeuse and the left foot is
the star Rigel, both zero magnitude (bright).
While observing Betelgeuse, think about this: It’s about 14 times the mass of our sun and its radius reaches an astounding 2.8 astronomical units (or, 2.8 times the distance between Earth and
the sun.) If it were the center of our solar system, Mercury, Venus, Earth and Mars would be toast.
Orion’s belt consists of Alnitak (the easternmost star, first magnitude), Alnilam (the middle star, first magnitude) and finally Mintaka,
the hardest one to view since it is second magnitude.
Let’s get Sirius. Tonight and for the next few nights, catch the star Sirius (in Canis Major) due south at midnight. It’s to the lower left of Orion. It’s bright at negative first magnitude.
Shortly after midnight in the eastern sky, Saturn rises. By 2 a.m., the ringed planet climbs the southeastern sky in the constellation Virgo. Then by 5 a.m., catch Saturn as it hangs high in the south-southeast. This large and gaseous planet is zero magnitude, bright.
By the end of January, Saturn rises just before 11 p.m.
Venus is sheer glory. It rises now before 4 a.m., and you can enjoy this luminous planet before the daily sun washes it out.
It’s a whopping negative fourth magnitude, very bright. Go out now between 6:15 and 7 a.m. to see Venus as a brilliant dot against the backdrop of dawn, in the east-southeastern sky.
Watch the old crescent moon near Venus on Jan. 29.
The following morning, the skinnier crescent will be closer to the horizon.
The fleet and nimble Mercury makes a cosmic cameo early in January. It rises now about 5:45 a.m. and hugs the horizon high enough for sky gazers to see. By mid-January, Mercury gets washed out by the sun’s glare.
With memories of “Snowmageddon” fresh in Washington’s memory, it may be ironic that Earth on Monday will reach perihelion – our planet’s closest point to the sun in the orbit around our star, according to the U.S. Naval Observatory.
On July 4, we reach aphelion, Earth’s most distant point from the sun.
Jan. 3 — “Stars Tonight” for January at the David M. Brown Planetarium, 1426 N. Quincy St., Arlington, adjacent to Washington-Lee High School. Hosted by Jonathan Harmon, director. $3 for adults, $2 for seniors and children. 7:30 p.m. Information, 703-228-6070. www.saveplanetarium.
Jan. 5 — Open house at the University of Maryland Observatory, College Park. Scan the heavens after astronomy lecture, weather permitting. 8 p.m. 301405-6555. www.astro.umd.edu/ openhouse.
Jan. 8 — Ruben Kier explains “ The Best Targets for Winter Astrophotography” at the National Capital Astronomers meeting, University of Maryland Observatory, College Park. 7:30 p.m.
Jan. 9 — Gary Hand, from Hands on Optics, Damascus, discusses consumer optics at the Northern Virginia Astronomy Club meeting, Room 80, Enterprise Hall, GeorgeMason University, Fairfax. 7 p.m. www.novac.
Jan. 20 — Open house at the University of Maryland Observatory, College Park. Telescope viewing follows astronomy lecture, weather permitting. 8 p.m. 301-405-6555. www.astro.
Jan. 29 — Forget “American Idol” as the birthplace of stars. Find out how real stars are born, as gravitationally controlled thermonuclear fusion reactors, in a program at the Montgomery College Planetarium, Takoma Park. 7 p.m. www.montgomerycollege.