Moon eclipsed on the 19th as dawn twilight floods our sky

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.

November brings some of our best stargazing nights of the year. Not only do we hold on to the Milky Way star fields of summer and a trio of bright planets in the evening, but we don’t need to wait long before Orion and the other spectacular constellations of winter climb into view in the east. We also look forward to a partial lunar eclipse before dawn on the 19th.

Edinburgh’s sunrise/sunset times change from 07:20/16:32 on the 1st to 08:18/15:45 on the 30th. The Moon is new on the 4th, at first quarter on the 11th, full during the eclipse on the 19th and at last quarter on the 27th.

The Moon takes six hours to traverse the southern region of Earth’s shadow on the 19th, from 06:02 to 12:04 GMT, but only the early stages of the eclipse are visible from Scotland as the Moon sinks towards our west-north-western horizon and the morning twilight floods the sky.

At 06:02, as the top edge of the Moon encounters the edge of the Earth’s penumbral shadow, it stands 13° above Edinburgh’s western horizon and 7° below the Pleiades star cluster in Taurus. Little darkening may be noticed until the Moon draws near to the central dark umbral shadow which it begins to enter at 07:19. The Moon sets for Edinburgh only thirty minutes later, though, when the umbra blankets the upper 40% of the Moon’s disk. The entire eclipse is observable from North America and most of the Pacific, culminating at 09:04 GMT when all but the southern 3% of the Moon lies within the umbra.

With our sky at nightfall changing only slowly, the Summer Triangle, formed by the leading stars Vega in the constellation Lyra, Altair in Aquila and Deneb in Cygnus, looms high on our meridian, though it tumbles into the west by our map times. By then, Capella in Auriga is the brightest star in the east while the Pleiades lie well to its right and above Aldebaran and the other stars of Taurus.

Orion is clambering above our eastern horizon but by midnight it stands 30° up in the south-east as the three stars of Orion’s Belt slant down to Sirius, the brightest star in our night sky. Midnight, too, sees Leo rising in the east-north-east with its bright star Regulus marking the handle of the Sickle, a reversed question-mark of stars that stand for the lion’s head and mane.

It is from within the Sickle that very swift meteors of the Leonids shower diverge every November. The shower persists from the 6th to the 30th and is expected to peak on the 17th or 18th but with strong moonlight swamping all but its brightest meteors in 2021. The Leonids are famous for producing intense meteor storms every 33 years, in line with the orbital period of the parent comet Temple-Tuttle, but few are expected this year and none at all before the Sickle rises.

The centre of the largely vacant Square of Pegasus stands some 55° high and due south as seen from Edinburgh at our map times, while the most remote object most of us can see with the unaided eye, the Andromeda Galaxy or M31, appears as a hazy ellipse 14° above and left of the Square’s top-left star, Alpheratz.

Underneath the Square, the Sun’s most remote planet, Neptune, is visible through binoculars as a magnitude 7.8 object 9° below the middle of the Circlet of Pisces (see map). The second farthest planet, Uranus, is seven times brighter at magnitude 5.7 and lies 11° below Hamal in Aries further to the east. It is 2,803 million km away and directly opposite the Sun at opposition at midnight on the 4th-5th.

Saturn and, more prominently, Jupiter remain on view in the lower southern sky at nightfall and set in the south-west between 90 minutes and three hours after our map times. Saturn lies some 15° to the right of Jupiter and 4° further south, while both are tracking eastwards (to the left) against the stars of Capricornus. Following oppositions in August, their distances are growing and they dim slightly, Saturn from magnitude 0.6 to 0.7 and Jupiter from magnitude -2.5 to -2.3.

The Moon lies below-left of Saturn on the 10th and is near first quarter when it sits below Jupiter on the 11th. On that evening, a telescope shows that Saturn’s 16 arcseconds wide disk is set within rings that span 37 arcseconds and have their north face tipped 19° towards us. Also on the 11th, Jupiter appears 41 arcseconds wide with all four of its main moons on display: Europa to the left of the disk and Io, Ganymede and Callisto to its right.

Brilliant and lower still is Venus which may be sighted low in the south-south-west immediately after sunset provided our sky and horizon are clear. Its altitude at Edinburgh’s sunset this month improves from 5° to 9° and by the 30th it sets more than two and a half hours after the Sun.

This month Venus brightens from magnitude -4.4 to -4.7, approaches from 97 million to 64 million km and swells in diameter from 26 to 39 arcseconds. It also shrinks in phase from 48% to 29% with the result that its dazzling crescent becomes discernable through binoculars. The planet makes an impressive sight to the left of the slender earthlit Moon on the 7th and to the Moon’s right on the 8th.

Mercury, nearing the end of a nice morning apparition, is bright at magnitude -0.8 when it stands 6° high in the east-south-east one hour before sunrise on the 1st. It lies 6° below the thin crescent Moon on the 3rd but is lost from sight over the next week. Mars, much fainter at magnitude 1.6, emerges from the Sun’s far side to pass close to Mercury on the 10th and stand low down in our south-eastern morning twilight at the month’s end.

Diary for 2021 November

  • 1st 02h Mercury 4° N of Spica
  • 3rd 12h Moon 6° N of Spica
  • 3rd 19h Moon 1.2° N of Mercury
  • 4th 21h New moon
  • 5th 00h Uranus at opposition at distance of 2,803m km
  • 8th 05h Moon 1.1° N of Venus
  • 10th 04h Mercury 1.1° N of Mars
  • 10th 14h Moon 4° S of Saturn
  • 11th 13h First quarter
  • 11th 17h Moon 4° S of Jupiter
  • 17th-18th Peak of Leonids meteor shower
  • 19th 09h Full moon and partial lunar eclipse
  • 19th 13h Moon 4° S of Pleiades
  • 20th 13h Moon 6° N of Aldebaran
  • 24th 04h Moon 2.5° S of Pollux
  • 25th 05h Moon 4° N of Praesepe
  • 26th 23h Moon 5° N of Regulus
  • 27th 12h Last quarter
  • 29th 05h Mercury in superior conjunction on far side of Sun
  • 30th 23h Moon 6° N of Spica

This is an extended version, with added diary, of Alan’s article published in The Scotsman on October 30 2021, with thanks to the newspaper for permission to republish here.