January Astronomy: The Moon and Various Planets Join Each Other to Create an Unusual Lineup

From late January through most of February, early risers can enjoy all five bright planets before dawn. The waning moon sweeps past four of these planets Dec. 31-Jan. 7, and past all five Jan. 27-Feb. 6.

One hour before sunrise, find brilliant Venus in the southwest, with Saturn nearby to its upper right Jan. 1-8, and to the lower left thereafter. These two planets are 8 degrees apart on Jan. 1, closing to 5 degrees on Jan. 4. On two mornings, they’ll form a spectacular close pair in the same telescopic field, within 0.7 degrees, on Jan. 8, and 0.5 degrees on Jan. 9. They’re still within 4 degrees on Jan. 12, widening to 7 degrees on Jan. 15.

Each day, Venus goes east against background stars by just more than 1.2 degrees, while Saturn goes by only 0.1 degrees, and Mars goes east about 0.5 degrees. Watch Venus pass 6 degrees north of first-magnitude Antares, heart of the Scorpion, on Jan. 7, and 3 degrees north of a third-magnitude star marking the top of the Teapot of Sagittarius on Jan. 28. Steady Saturn is 6.3 degrees to 7.5 degrees from reddish twinkling Antares this month, and stays 6-9 degrees from that star throughout Saturn’s current apparition, which ends when the planet sinks into the evening twilight in November 2016.

Bright Jupiter, in the southwest to west-southwest an hour before sunup, barely moves against stars this month, but it will shift 10 degrees west over four months, Jan. 8 to May 9. This apparent temporary reversal of Jupiter’s motion is centered on the planet’s opposition and all-night visibility on the night of March 7-8. This retrograde motion is a consequence of the faster-moving Earth overtaking the giant planet.

Mars is in the south-southeast to south in this month’s morning sky, 6 degrees to 21 degrees east of Spica. On Feb. 1, Mars will pass 1.1 degrees north of third-magnitude Alpha in Libra. Once Mercury emerges from the sun’s glare in late January, all five naked-eye planets will be on display, in the order Me-Ve-Sa-Ma-Ju, in an impressive panorama across the southern morning sky. Mercury brightens from magnitude +1.2 to 0.0 at dawn in last 10 days of January, and continues to brighten into February.

Jupiter (magnitude -2.3 in mid-January) and Saturn (magnitude +0.5), with its ring system now tipped 26 degrees from edge-on, are favorites for telescopic viewing. They’re in the sky simultaneously mornings in the early months of 2016, and evenings from late spring into summer. Bright Venus (magnitude -4) in January shrinks to 0.2’ (arcminute) across, while increasing from 77 percent to 85 percent illuminated. Venus and Saturn appear within the same telescopic field on Jan. 8 and 9. Red Mars (magnitude +1.3 to +0.8) starts 2016 as a tiny disk 0.1’ across, nearly full. By opposition and closest approach in late May, Mars will triple in apparent size and match Jupiter in brilliance!

Follow the waning moon before dawn, near Jupiter, on Dec. 31, near Mars and Spica on Jan. 3, and near Venus, Saturn and Antares on Jan. 6 and 7.

Look for the moon within an hour after sunset each evening Jan. 10-23, as it waxes from crescent to full.

On Thursday, Jan. 14, Mercury is at inferior conjunction, as the planet goes between the Earth and the sun, while passing north of the solar disk.

In mid-January, the Summer Triangle of Vega–Altair–Deneb is visible at both dusk and dawn. Evenings, once Sirius has risen in the east-southeast, look for the Winter Hexagon of Sirius–Procyon–Pollux–Capella–Aldebaran–Rigel–Sirius, with Betelgeuse inside.

On Sunday and Monday, Jan. 17 and 18: Venus and Mars are 45 degrees apart in the morning sky. On Jan. 18, Ve-Sa-Ma-Ju span 90 degrees. Ma-Ju are 45 degrees apart.

Tuesday, Jan. 19: The moon’s leading dark edge, invisible in daylight, occults or covers Aldebaran, eye of Taurus the Bull, around sunset in the Coachella Valley. Times of star’s disappearance and reappearance for Palm Springs: 5:06 p.m. and 6:16 p.m. A telescope is best for viewing these events. After the star reappears, check at various times during the evening and watch the moon pull away from the star.

During Jan. 23-Feb. 7 in the morning sky, watch the waning moon go east against the zodiacal backdrop, posing near Regulus on Jan. 25 and 26, near Jupiter on Jan. 27 and 28, and just 4 degrees north of Spica on Jan. 30.

Illustrations of events mentioned above appear in the Sky Calendar. The sample excerpt on the next page depicts events such as the gathering of moon, Venus and Saturn on the mornings of Jan. 7-8. To subscribe, visit www.abramsplanetarium.org/skycalendar.

The Whitewater Preserve will host a star party on Saturday, Jan. 2, from 5 until 8:30 p.m. For information, call 760-325-7222.

To provide a chance for locals to view the unusual lineup of the moon and four or five planets, I will hold three predawn sky watches this month, if the sky is clear. The first will be held on the first clear morning of Wednesday, Jan. 6, or Thursday, Jan. 7, to view a compact gathering of the waning crescent moon with Venus and Saturn. The second will be held on the first clear morning of Friday, Jan. 8, or Saturday, Jan. 9, to view Venus and Saturn simultaneously within a telescope field. The third session will be held on the first clear morning of Sunday, Jan. 31, or Monday, Feb. 1, to view the lineup of all five naked-eye planets and the moon. All three watches will be held in Palm Springs, from 5:15 until 6 a.m., on the pedestrian bridge crossing over Tahquitz Creek, at Camino Real between north and south Riverside drives, three blocks north of Cahuilla Elementary School.

The Astronomical Society of the Desert will host a star party on Saturday, Jan. 16, at dusk at the Visitor Center of the Santa Rosa and San Jacinto Mountains National Monument. More information is available at www.astrorx.org.

I will present a preview of sky events of 2016 on Friday, Jan. 29, at the Portola Community Center in Palm Desert. Socializing begins at 6:30 p.m., with the lecture at 7 p.m.

Robert C. Victor was a staff astronomer at Abrams Planetarium at Michigan State University. He is now retired and enjoys providing skywatching opportunities for school children in and around Palm Springs. Robert D. Miller, who provided the twilight charts and the planet orbit charts, did graduate work in planetarium science and later astronomy and computer science at Michigan State University and remains active in research and public outreach in astronomy.