Starwatch: The October night sky​

Our October nights begin with the Summer Triangle of Vega, Deneb and Altair high in Britain’s S sky as the Square of Pegasus climbs in the E and the Plough is unmistakable in the NW. By our map times, though, the Triangle has toppled over into the W to be replaced in the S by the Square while the Plough is nearing its familiar autumnal low-point below Polaris in the N.

Venus blazes at mag –3.9 to –4.0 well up in the W evening sky as seen from S of the equator. For Britain, though, it is barely 6° high in the SW at sunset at present and sets some 50 minutes later. By the 31st, it is only one degree higher, but stays visible for 80 minutes.

Saturn, low in the SW after Venus sets and darkness descends, shines at mag 0.6 above Antares in Scorpius. To its left, and slightly higher and brighter at mag 0.1 to 0.4, is Mars, which tracks E above the Teapot of Sagittarius, clipping Kaus Borealis, the finial atop the teapot’s lid, on the 7th. As Venus speeds away from the Sun, it passes 3° S of Saturn on the 30th.

Catch the Moon 4° above-right of Venus on the 3rd, 6° above-left of Saturn on the 6th and 7° above Mars on the 8th. As the full moon following September’s harvest moon, folklore dictates that the one on the 16th is the hunter’s moon. Two nights later, on the 18/19th, the Moon hides several stars in the Hyades cluster as it approaches Taurus’s leading star Aldebaran, and eventually occults Aldebaran itself for watchers in the USA SE of a line from the Great Lakes to Los Angeles.

Mercury shines brightly very low in the E before sunrise early in the month, but its apparition is almost over by the 11th when it stands only 0.8° above-left of Jupiter as the latter emerges from the Sun’s glare. Jupiter is conspicuous at mag –1.7 and well up in the ESE before dawn by the 28th, when it lies below the impressively earthlit Moon.

The Orionids meteor shower is active during the morning hours from the 16th and peaks from the 21st to 24th. Its swift meteors, many leaving trains in their wake, derive from Halley’s comet and diverge from a point to the NE of Betelgeuse in Orion’s shoulder.

October diary

1st 01h New moon

3rd 18h Moon 5° N of Venus

6th 09h Moon 4° N of Saturn

8th 13h Moon 7° N of Mars

9th 06h First quarter

11th 05h Mercury 0.9° N of Jupiter

15th 12h Uranus at opposition

16th 05h Full moon (Hunter’s moon)

19th 08h Moon 0.3° N of Aldebaran

21st-24th Peak of Orionids meteor shower

22nd 20h Last quarter

27th 17h Mercury in superior conjunction

28th 11h Moon 1.4° N of Jupiter

30th 02h BST = 01h GMT End of Summer Time; 08h Venus 3° S of Saturn; 18h New moon

* Times are BST until 30th