The Sky Above You, October 2025
by Duncan Lunan
On September 22nd, Grahame Gardner photographed equinox sunrise at the new location of the Sighthill stone circle, which I designed and built for Glasgow Parks Department in 1978-79. That completes the set of solar alignments visible from the new location, with images of midsummer sunrise in 2023, and midwinter sunrise and sunset in 2024. Dr. Alan Cayless has kindly processed the images for me, and the results will tell us just how accurate those new alignments are. Midwinter sunset looks spot on. (Midsummer sunset and equinox sunset are both hidden by new buildings, for now.) I'm keeping a watch on the weather in hopes that someone can photograph the Moon near its major standstill positions for me.
On September 24th SpaceX launched an important trio of satellites towards the Sun-Earth L1 point, a million miles towards the Sun from here. The Carruthers Geocorona Observatory is named after George Carruthers, inventor of the ultraviolet telescope taken to the Moon by Apollo 16 in 1972, which imaged the upper atmosphere of the Earth. The Carruthers observatory will image the outwards extension of the atmosphere to beyond the orbit of the Moon. The National Oceanic and Atmospheric Administration (NOAA) Space Weather Follow On-Lagrange 1 satellite (SWFO-L1) will monitor the solar wind and watch for Coronal Mass Ejections, which pose a significant threat to future crewed lunar missions, and the Interstellar Mapping and Acceleration Probe (IMAP) will continue the mapping of the outer reaches of the heliosphere, begun by the ILEX orbiter which is scheduled to be switched off if the White House's cuts to the programme go ahead. It's to be hoped the IMAP launch won't be used to justify all of the cuts, which threaten 41 current or future space missions,
The Moon is Full on October 7th, a 'supermoon' at its closest to the Earth, and it will be New on October 21st when at its furthest. The Moon passes Saturn and Neptune on the 5th and 6th, occulting Saturn on the 6th, crosses the western edge of the Pleiades on the 10th (best seen from the north of Scotland), is near Jupiter at Last Quarter on the 13th and 14th, and is near Venus on the 19th. British Summer Time ends on October 26th, when the Moon is near Regulus in Leo.
I've been aware for some years that there was controversy about a possible ancient impact in what's now the North Sea, though I couldn't find any details. It turns out that the feature was discovered in 2002; it's 80 miles off the Yorkshire coast and 700 metres below the present seabed, and until recently many geologists didn't believe that it was an impact feature (The Science Desk, 'Scientists Finally Solve 20-Year Mystery of the Crater Hidden Beneath the North Sea', Science News Today, online, 23rd September 2024), but a new survey by Heriot-Watt University has settled the question and dated the event to 43-46 million years before present. The impactor was about 160 metres across and came from the west, forming a crater 3 km across and a surrounding 20-km ring of concentric rings and radial fractures, where samples retrieved from exploratory oil drilling decades before show shocked quartz and feldspar, characteristic impact features. (See 'The Sky Above You, June 2025', Orkney News, 3rd June, 2025). The event threw up a 'wall of water' more than 1.5 km high, with a huge overhang which collapsed into 100-metre tsunamis, dramatically illustrated by a YouTube graphic in 'Evidence of an ancient asteroid impact in the North Sea' (Kelly Kizer Whitt, EarthSky, September 25th 2025). It shows how long it took for the 'hole in the sea' to quench and fill the crater afterwards, continuing to generate fresh waves as it did so. A somewhat fanciful representation of something similar about to strike the present Yorkshire coast shows little sign of a plasma sheath, which alone would be deadly, and precedes the blast, the ground shock and the waves, but the event shows how much devastation could be caused by a comparatively small impactor; hopefully, it also shows that the White House plan to cancel the Osiris mission to the Potentially Hazardous Asteroid Apophis is a really bad idea.
The planet Mercury is not visible from the UK this month, although at greatest elongation from the Sun on the 29th. Mercury will then be near Mars, but to see them Astronomy Now recommends the view from Sydney, Australia.
Venus in Leo rises at 5.30 a.m., passing into Cancer on the 8th, very bright although low in the sky, with Jupiter high in the south at the same time. Venus is approached by the waning crescent Moon on the morning of the 19th.
Mars is out of sight behind the Sun this month, during which it's passed by both the Moon and Mars in daylight on October 21st.
ESA's Rosalind Franklin Mars rover, part of the Exomars project from which NASA withdrew, is scheduled for launch in 2027. There was full Russian participation including the launch, before the invasion of Ukraine, and the carrier vehicle is now being provided by Thales Alenia Space, with the lander from the British Aerospace division of Airbus. In May 2024 ESA signed a new agreement for NASA to 'procure a launch vehicle' for the mission, but there's a remarkable reticence online to say what it will be. However the chosen landing site in Oxia Planum, which was shortlisted as a target for both the Curiosity and Perseverance landers, is now looking even more promising in the search for past life, as a result of the findings of Perseverance in and above Jezero crater. (Paul Scott Anderson, 'Rosalind Franklin rover: Finding Mars life might be easy', EarthSky, September 22nd, 2025.)
Reporting in May on the flyby of the asteroid Donaldjohanson the previous month, I expressed mild disappointment that so far we'd seen only part of one side of it. Even small objects can hold considerable surprises in that situation, as witness the Hope orbiter's flyby of Deimos, the outer moon of Mars. Although it had been imaged by multiple spacecraft since 1971, all of them had shown only the side facing the planet, and when the other side was photographed by Hope, it revealed a huge cleft whose existence was previously unsuspected, suggesting that the moon was formed by the collision of two or more smaller bodies.
Donaldjohanson was named after the discoverer of the famous 'Lucy' hominid fossil, and it too turns out to be a 'contact binary', with a smooth neck joining the components where dust from them has flowed downslope, even in the asteroid's low gravity. The major features have now been named after sites in and around Olduvai Gorge and of other ancient fossil hominids. Brief explanations are attached to the captions, and there are more details in Elizabeth Howell, 'Asteroid Donaldjohanson Honors Ancient Human History', Space.com, September 25th 2025. If more names are proposed after more detailed studies, it will be interesting to see whether they include Sir Vivian Fuchs, who was one of the Olduvai Gorge team before becoming famous as the leader of the 1953 Everest expedition and the Commonwealth Trans-Antarctic Expedition (see 'The Asteroid Hunter', ON, 14th September 2025).
It looks as if the flyby was too fast for images to be obtained of the other side of it. As Donaldjohanson was a 'target of opportunity' on the Lucy probe's mission to the Trojan asteroids in the orbit of Jupiter, it's likely to be a very long time before we see the other side of it.
Jupiter in Gemini now rises around 11 p.m., below Castor and Pollux, and is brilliant for the rest of the night, passed by the Moon on the 13th and 14th. On the morning of the 19th the second largest Jovian moon Callisto crosses the face of Jupiter, a relatively rare event, and on the mornings of the 22nd and 29th, Io is in transit along with its shadow and Europa's.
Saturn in Pisces is near the Moon on the night of 5th-6th October, setting about 5 a.m.. Nigel Henbest's Stargazing 2025 says it 'passes over' Saturn, but I think that means 'above', because there's no mention of an occultation in the Collins 2025 Guide to the Night Sky or in the October Astronomy Now, which says they will be 4 degrees apart. Titan, the second largest moon in the Solar System, transits the planet on the night of October 21st/22nd, and is occulted by it on the evening of the 29th. For more details see this month's Astronomy Now.
The James Webb Space Telescope has detected mysterious features, dark blobs within Saturn's north polar aurora and a starfish-like feature, oriented to the corners of the hexagon-like feature in the storms below. Little more is known at present. (Sharmila Kuthunur, 'JWST finds 'dark beads' and wonky star patterns in Saturn's sky: "These features were completely unexpected"', Space.com, September 25th, 2025.)
Uranus rises at 7.30 p.m., below the Pleiades in Taurus, passed by the Moon on the 10th.
Neptune in Pisces is to the left of Saturn, setting around 5.30 a.m., passed by the Moon on the 6th.
The Draconid meteor shower is on October 8th, and although sparse, may generate fireballs from Comet Giacobini-Zimmer, which was visited by the International Comet Explorer in 1986, before it went on to Halley's Comet, passing through the tails of both. Halley's is the source of the Orionid meteors, which are particularly visible on the 21st-22nd because the peak is just after New Moon. Another shower, the South Taurids, peaks on October 10th, but will be less visible so soon after Full Moon.
A poem by Ibn Sana’ al-Mulk, in praise of Saladin during his wars with the Crusaders, has been recently dated, by historical references in it, to between December 1181 and May 1182. (Shireen Gonzaga, 'Supernova 1181 was described in an ancient Arabic poem', EarthSky, September 19th 2025.) It coincides with a supernova in Cassiopeia, recorded by Chinese astronomers as 'bright as Saturn', between August 6th 1181 and February 6th 1182. Until now the poem's description has been confused with a conjunction of the planets in Libra, in 1184 or 1185 (mediaeval records are often confusing). But a new translation of the key stanzas by J. G. Fischer, at the University of Münster’s Institute for Arabic and Islamic Studies in Germany, makes clear that it describes a single object in the sky, in an Arabic constellation called the Henna-Dyed Hand, taking in the five brightest stars of Cassiopeia. It was thought to be supernova 3C 58, whose remnant is visible in the area, but that has turned out to be 3-5000 years old, no longer a candidate.
The best one now is PA 30, 10,000 light-years away and visible about 1000 years ago, outside the main figure of the constellation but within its boundary. It's of great interest for two reasons: it was a rare Type 1Ax supernova, caused by the collision of two white dwarf stars; and a similar white dwarf merger is the main event of the novel Slow Gods, by Claire North (Orbit Books, in press for 18th November 2025). I'm currently reviewing an advance copy for Shoreline of Infinity, and since the book is set entirely in space, I expect that another version of the review will appear in my 'Space Notes' for Orkney News in due course.
Duncan Lunan’s recent books are available through Amazon; details are on Duncan’s website, www.duncanlunan.com.
The Sky Above You
By Duncan Lunan
About this Column
I began writing this column in early 1983 at the suggestion of the late Chris Boyce. At that time the Post Office would allow 1000 free mailings to start a new business, just under the number of small press newspapers in the UK at the time. I printed a flyer with the help of John Braithwaite (of Braithwaite Telescopes) offering a three-part column for £5, with the sky this month, a series of articles for beginners, and a monthly news feature. The column ran from May 1983 to May 1993 in various newspapers and magazines, but never in more than five outlets at a time, although every one of those 1000-plus papers would have included an astrology column. Since then it’s appeared sporadically in a range of publications including The Southsider in Glasgow and the Dalyan Courier in Turkey, but most often, normally three times per year, in Jeff Hawke’s Cosmos from the first issue in March 2003 until the last in January 2018, with a last piece in “Jeff Hawke, The Epilogue” (Jeff Hawke Club, 2020). It continues to appear monthly in Troon's Going Out and Orkney News, with an expanded version broadcast monthly on Arransound Radio since August 2023
The monthly maps for the column were drawn for me by Jim Barker, based on similar, uncredited ones in Dr. Leon Hausman’s “Astronomy Handbook” (Fawcett Publications, 1956). Jim had to redraw or elongate several of them because they were drawn for mid-US latitudes, about 40 degrees North, making them usable over most of the northern hemisphere. The biggest change needed was in November when only Dubhe, Merak and Megrez of the Big Dipper, as the US version called it, were visible at that latitude. In the UK, all the stars of the Plough are circumpolar, always above the horizon. We decided to keep an insert in the January map showing the position of M42, the Great Nebula in the Sword of Orion, and for that reason, to stick with the set time of 9 p.m., (10 p.m. BST in summer), although in Scotland the sky isn’t dark then during June and July.
To use the maps in theory you should hold them overhead, aligning the North edge to true north, marked by Polaris and indicated by Dubhe and Merak, the Pointers. It’s more practical to hold the map in front of you when looking south and then rotate it as you face east, south and west. Some readers are confused because east is on the left, opposite to terrestrial maps, but that’s because they’re the other way up. When you’re facing south and looking at the sky, east is on your left.
The star patterns are the same for each month of each year, and only the positions of the planets change. (“Astronomy Handbook” accidentally shows Saturn in Virgo during May, showing that the maps weren’t originally drawn for the Hausman book.) Consequently regular readers for a year will by then have built up a complete set of twelve.
©DuncanLunan2013, updated monthly since then.