Starwatch: the January night sky

Orion, which rises in the E at nightfall and passes due S two hours after our map times, rules a star-spangled evening sky that more than compensates for the fact that our only bright planets are visible before dawn.

The Moon is also conspicuous at present, reaching its full phase at 02:25 GMT on the 2nd, only four hours after it is at its closest point for the whole of 2018. As the best so-called “supermoon” of the year, it appears 17% wider than it does at its farthest.

The 31st sees the Moon track through the S half of Earth’s shadow in a total lunar eclipse. Its disc lies entirely within the dark umbral shadow between 12:42 and 14:08 but no stage of the eclipse is visible from Britain.

The Quadrantids meteor shower lasts from the 1st to the 6th with a sharp peak around 21:00 on the 3rd when up to 80 meteors per hour might be counted by an observer under an ideal dark sky. Moonlight swamps the scene this year, though, so expect to glimpse only a fraction of these. The meteors diverge from a radiant that lies low in the N at our map times and follows the Plough high into the E before dawn.

Jupiter dominates the final hours of the night as it climbs through the SE into the S. It brightens from mag –1.8 to –2.0 this month as it creeps to the E against the stars of Libra. Mars, much fainter at mag 1.5 to 1.2, lies 2.6° above-right of Jupiter and close to the double star Zubenelgenubi on the 1st but moves more quickly E to slip just 0.2° below Jupiter on the 7th and ends the month 12° to Jupiter’s left. Catch them both below the waning Moon on the 11th.

Mercury, bright at mag –0.3, hovers just above our SE horizon in the morning twilight at present but will be a difficult target by mid-month when it is passed by Saturn and the Moon. Saturn, mag 0.5 in Sagittarius, rises two hours before the Sun by month’s end.

It has been my delight and privilege to have contributed our night sky and Starwatch notes for the past 43 years, but the time has come to step down and pass the reins of the next-generation Starwatch to the respected author and astronomy journalist Stuart Clark. Clear skies to all Starwatchers.

January diary

1st 20h Mercury furthest W of Sun (23°)

2nd 02h Full moon (supermoon)

3rd 06h Earth closest to Sun (147,100,000 km); 21h Peak of Quadrantids meteor shower

5th 08h Moon occults Regulus

7th 04h Mars 0.2° S of Jupiter

8th 22h Last quarter

9th 07h Venus in superior conjunction

11th 06h Moon 4° N of Jupiter

13th 07h Mercury 0.6° S of Saturn

15th 02h Moon 2.6° N of Saturn; 07h Moon 3° N of Mercury

17th 02h New moon

24th 22h First quarter

31st 13h Full moon and total lunar eclipse