Jupiter at its impressive best as the Moon hides Venus

Alan Pickup

Author: Alan Pickup

The maps show the sky at 21:00 GMT on the 1st, 20:00 on the 16th and 19:00 on the 30th. An arrow shows the motion of Jupiter.

Jupiter and Venus provide our prime planetary interest this month, but our nights offer plenty of stellar sights too, from the star fields of the Summer Triangle, still lingering high in the south to south-west as darkness falls, to Orion and his glorious retinue later in the night.

Jupiter, now at its best, is conspicuous as it sails high across our southern sky from the east-north-east at nightfall to the west-north-west before dawn. The giant planet reaches opposition, on the opposite side of the sky to the Sun, on the 3rd when it sits 596 million km away, blazes at magnitude -2.9 and appears 47 arcseconds wide through a telescope. It recedes by 19 million km this month, dimming slightly to magnitude -2.8.

As depicted on our south star chart, Jupiter lies some 20° to the west-south-west of the Pleiades cluster and tracks almost 4° westwards in southern Aries over the period. The chart also plots Uranus between Jupiter and the Pleiades although, at magnitude 5.6, it is near the limit of naked-eye visibility in a dark sky. This, too, reaches opposition when it stands 2,787 million km away on the 13th, with telescopes showing its tiny 4 arcsecond disk.

Io and its shadow on Jupiter. Mark Phillips 2023-10-14

Directed towards Jupiter, those telescopes reveal cloud bands, mostly of ammonia, that lie parallel with its equator and include streaks and spots such as its famous Red Spot. Given that the planet rotates in just under ten hours, these features appear to sweep across its face in only five hours so that an overly-enthusiastic observer might view its entire surface during a single night.

Its four main moons may just be glimpsed through steadily-held binoculars though their changing configuration to the east and west of the disk is much easier to follow telescopically. The three inner ones, Io, Europa and Ganymede, sometimes pass in front of the disk, casting their inky black shadows onto the Jovian clouds below.

Venus has no known moons, but it, too, is blanketed by clouds. For Venus, though, these are brilliant white and of sulphuric acid, with barely any hint of detail unless we employ special filters.

Venus in infrared light taken by David Brett, 2023-10-17

Fading only a shade this month from magnitude -4.3 to -4.2, the dazzling morning star rises at Edinburgh’s eastern horizon at 02:39 on the 1st, and by 03:53 on the 30th, climbing well up into the south-east before dawn. Seen through a telescope, it shrinks from 22 to 17 arcseconds across while its phase changes from 55% to 68% sunlit. Venus speeds 33° eastwards and south though Virgo to end the month 4° above and left of Spica.

There is a more impressive conjunction on the morning of the 9th when Venus is occulted in daylight by the waning crescent Moon, 16% sunlit. Before dawn on that morning, Venus is less than 2° below-left of the Moon. Telescopes should keep them both in view well beyond sunrise (07:36 for Edinburgh). At 09:36 Venus takes more than a minute to disappear behind the bottom sunlit edge of the Moon, only to emerge at the Moon’s dark right-hand edge exactly one hour later.

The Sun dips 7.5° further south in the sky as Edinburgh’s sunrise/sunset times change from 07:19/16:33 on the 1st to 08:17/15:45 on the 30th.

The Moon reaches last quarter not far from the Praesepe star cluster in Cancer on the morning of the 5th and lies alongside the Sickle of Leo on the 6th. Following its meeting (and daylight occultation) with Venus on the 9th it become more impressively earthlit for a close encounter with Spica in Virgo before dawn on the 11th. New Moon occurs on the 13th and first quarter on the 20th, just hours before it stands below Saturn in our southern evening sky. The bright Moon stands alongside Jupiter on the 25th and is full when it meets the Pleiades in Taurus on the 27th.

Our charts show the Summer Triangle (Vega, Deneb and Altair) in the middle of the western sky as Orion rises above our eastern horizon and it is the turn of the Square of Pegasus to cross the meridian. Three of the stars of the Square belong to Pegasus but its top-left corner is marked by Alpheratz in Andromeda, though at one time Alpheratz was claimed by both constellations.

South of Pegasus is the region of sky which, because of its surfeit of “watery” constellations, is sometime known as the celestial sea or ocean.

Here we find aforementioned Saturn, the first of our evening planets. Close to the boundary between Capricornus, the Sea Goat, and Aquarius, the Water Bearer, it hardly moves during November, being apparently stationary on the 4th when its motion against the stars reverses from westerly to easterly. It dims a little from magnitude 0.7 to 0.8 this month but remains the most obvious object lower down in our south to south-west until it sets more than three hours after the map times.

We need (at least) binoculars and a dark sky to glimpse the dim magnitude 7.8 world Neptune which lies 5° below the loop of stars we call the Circlet of Pisces, just under the Square. Below Pisces the Fish is Cetus the Whale which extends almost to Jupiter, and Eridanus the River flowing all the way to Orion.

Of the remaining planets, Mercury is too low to be seen in our evening twilight while Mars passes through conjunction around the Sun’s far side on the 18th.

Leonid meteor caught by Tosh White’s meteor camera 2022-11-24

November’s main meteor shower, the Leonids, has produced some impressive storms in the past but is expected to be a desultory affair this time. Lasting from the 6th to the 30th, its sharp peak may yield only 15 very swift meteors per hour under the darkest of skies on the morning of the 18th. These diverge from the Sickle of Leo, the curl of stars above Regulus which is rising in the east-north-east at midnight and high on the meridian before dawn.

Diary for 2023 November

  • 3rd 05h Jupiter in opposition at distance of 596m km
  • 3rd 19h Moon 1.4° S of Pollux
  • 4th 17h Saturn stationary (motion reverses from W to E)
  • 4th 20h Moon 4°N of Praesepe
  • 5th 09h Last quarter
  • 6th 17h Moon 4° N of Regulus
  • 9th 10h Moon occults Venus in daylight
  • 11th 06h Moon 2.4° N of Spica
  • 13th 09h New Moon
  • 13th 17h Uranus at opposition at distance of 2,787m km
  • 18th 06h Mars in conjunction with Sun
  • 18th 06h Peak of Leonids meteor shower
  • 20th 11h First quarter
  • 20th 14h Moon 2.7° S of Saturn
  • 25th 11h Moon 2.7° N of Jupiter
  • 27th 01h Moon 1.1° S of Pleiades
  • 27th 09h Full Moon
  • 27th 21h Moon 9° N of Aldebaran
  • 28th 09h Venus 4° N of Spica

This is an extended version, with added diary, of Alan’s article published in The Scotsman on 31 October 2023, with thanks to the newspaper for permission to republish here.