The Astronomical Sky Above Edinburgh and Lothian showing celestial events and tips on what you will see if you look up this month.
The October sky over Edinburgh and Lothian sees a Lunar eclipse and 5 meteor showers but—hold on to your hats—these events will, in the main, not be the most spectacular show. If you do want a spectacular show, consider visiting North America, Central America or South America on the 14 October and watch an annular (Solar) eclipse streak across the Earth!
October’s highly visible Lunar eclipse occurs when the Moon lies within the Earth’s shadow and the Moon (in the umbra) can take on a coppery-red hue. For Edinburgh and Lothian, the (penumbral) eclipse will begin on 28 October at 7:02 pm in Aries. The umbral eclipse will begin at 8:35 pm and peak at 9:14 pm. At best, though, only about 6% of the Moon’s disk will be covered by the Earth’s umbra—clipping the edge, really—before the umbral phase ends at 9:53 pm. The (penumbral) eclipse ends at 11:26 pm. Approximately 6 billion people, worldwide, will be able to see the entire eclipse and the population of Edinburgh and Lothian is amongst them.
Yet we get ahead of ourselves: during autumn, the Sun’s peak altitude continues to dip lower in the sky as the Sun starts its October stroll in Virgo and enters Libra on 31 October at 12:14 pm. Daylight shortens from 11.564 hours to 9.307 hours so we gain 2 hours and 15 minutes of night time by the end of the month.
The Moon enters last quarter on 6 October at 2:48 pm in Gemini. Lunar apogee (furthest from Earth) follows on 10 October at 4:49 am and takes the Moon to 405394 km away from Earth, 20994 km further than normal, subtending an angle of 29.47 minutes of arc. The new moon appears on 14 October at 6:55 pm in Virgo beginning a new synodic (Lunar) month. The first quarter of the new cycle shows up on 22 October at 4:29 am in Sagittarius. Lunar perigee (closest to Earth) on 26 October at 4:11 am finds the Moon some 364894 km away from Earth, 19506 km closer than normal, subtending an angle of 32.74 minutes of arc. Late in the month, the full Hunter’s Moon makes an appearance on 28 October at 9:24 pm in Aries.
For the inner planets, Mercury passes through superior conjunction—behind the Sun—in the second half of October so is mostly unobservable except for the first week when it will be bright at -1.1 mag but low in the eastern morning sky. Venus, however, reaches greatest western elongation on 24 October at 0:16 am and will be easily visible as a morning object, all month in the eastern sky, in Leo hovering around -4.7 mag. For the superior planets: Mars is a washout in the Sun’s glare. Jupiter at -2.8 mag is visible all month long in Aries and the best time to observe it will be during the eclipse since it will be a few degrees east of the eclipsed Moon and appear to shine more brightly as the Moon fades. Saturn at 0.6 mag is best observed in the evening in Aquarius and is near the waxing gibbous Moon on 23–24 October. Uranus will be in Aries at the naked-eye limit at 5.7 mag, not far from Jupiter, whereas Neptune at 7.7 mag will require binoculars or a telescope but is well-placed for evening viewing in Pisces.
For 2-body conjunctions between solar system objects (defined as being less than 5 degrees apart), there are 2 that will be visible both involving Jupiter and the Moon. There are others but they are either washed out by the Sun or the objects fail to rise above the local horizon. The first Jupiter–Moon conjunction, early in the month and before the eclipse, will peak on 2 October at 2:11 am when the Moon and Jupiter will be 3.15 degrees apart. The second Jupiter–Moon conjunction will be post-eclipse and occur on 29 October at 6:13 am and Jupiter will be bright but low in the west at 2.89 degrees from the Moon in twilight. An hour or two earlier would be better.
Shooting star watchers will have several opportunities as there are no fewer than 5 meteor showers of varying degrees of visibility but only 2, realistically, that might put on a show. The Draconids, radiant from the constellation Draco (The Dragon), will peak 8–9 October and result from the Earth passing through the debris of comet 21P/Giacobini-Zinner deposited during its last perihelion in September 2018. Look towards the star Rastaban in the head of the dragon, between the North Ecliptic Pole (NEP) and M92 on the skymap, in the evening and overnight hours. The Orionid meteor shower, radiant from the constellation Orion (The Hunter), will provide the best observing opportunity any time after 2 October, peaking on 21–22 October. At that time, a first-quarter Moon makes for good viewing so expect 10–20 meteors per hour (rising) in the very late evening and overnight. Look between the stars Betelgeuse on the shoulder of Orion and Alhena in the feet of Gemini (The Twins). The parent comet of the Orionids is the famous Halley’s Comet.
Constellations visible in October include Camelopardalis (The Giraffe), Pegasus (The Winged Horse), Andromeda (The Chained Maiden), Auriga (The Charioteer), Lacerta (The Lizard), along with our circumpolar friends Cassiopeia (The Seated Queen), Draco (The Dragon), Ursa Minor (The Little Bear), Cepheus (The King). The pseudo-constellation known as the Summer Triangle—comprising the bright stars Vega in Lyra (The Lyre), Deneb in Cygnus (The Swan) and Altair in Aquila (The Eagle)—continues to fall deeper into the west.
Finally, don’t forget to turn the clocks back as British Summer Time (BST) officially ends on 29 October at 2:00 am when the time becomes 1:00 am GMT.
The sky above Edinburgh and Lothian at midnight on 15/16 October. The figure also applies at 1 am on 1 October and 10 pm on 30 October. The green, dashed, line is the Ecliptic and the brown, dashed, line is the Milky Way. Asterisms below 10 degrees may be truncated because of distortion. To use the map, face any direction and then rotate the map until that cardinal point is nearest to you. The zenith (point directly overhead) is at the centre of the circle and the edge is the horizon.
Phil Daly is a former employee of the Royal Observatory Edinburgh (now UKATC) on Blackford Hill.
He has worked on the UK's overseas telescopes in Hawaii (UKIRT, JCMT) and on large telescopes
at major astronomical observatories worldwide. He is currently part of an international collaboration
searching for optical counterparts to gravity wave events using multi-messenger astronomy.
