Indholdsfortegnelse for November 2025 i BBC Sky at Night

More than half a century since humans last visited our lunar neighbour – or indeed travelled beyond low Earth orbit – NASA has announced plans to send four astronauts around the Moon. The Artemis II mission was originally planned for April 2026, but the agency now says it could launch as early as 5 February. The crew – Americans Reid Wiseman, Victor Glover and Christina Koch, and Canadian Jeremy Hansen – will embark on a 10-day voyage to “explore the Moon for scientific discovery, economic benefits, and to build the foundation for the first crewed missions to Mars”. The flight is part of the Artemis programme, which aims to establish a sustainable human presence on the Moon. Although the mission won't land on the lunar surface, it will take the…

JWST's discovery of ‘little red dots’ in 2022 seemed to upend what we understood about how the Universe formed. Red, compact and completely unexpected, they were thought to be an unusually early type of galaxy that formed 700 million years after the Big Bang. Dubbed ‘Universe breakers’, the red objects appeared to be either massively heavy galaxies or modestly sized ones, each with a supermassive black hole at its core. Either way, it was thought that these galaxies shouldn't have had time to get as large and dense as they appear. New research now suggests the Universe may not be quite as broken as we thought. It proposes that these dots may not be galaxies at all, but a new type of object called a ‘black hole star’ (or BH*).…

A new supernova may soon light up our skies. An international team of astronomers have been studying a greedy white dwarf in a binary star system called V Sagittae, which is just 10,000 lightyears from Earth. It's burning unusually brightly as it speedily consumes its much larger companion star. In fact, it's stripping this stellar material so fast it can't handle all of it, creating a halo of shining gas which surrounds both stars. “V Sagittae is no ordinary star system,” says Phil Charles from Southampton University, one of the study's authors. “It's the brightest of its kind and has baffled experts since it was discovered in 1902. Our study shows that this extreme brightness is down to the white dwarf sucking the life out of its companion star, using…

On 15 August 1977, Ohio State University's ‘Big Ear’ radio telescope picked up an extremely strong, 70-second narrowband signal originating from somewhere in the constellation Sagittarius, the Archer. When volunteer Jerry Ehman checked the receiver output – an old-fashioned strip of paper from a line printer – he noticed the character string 6EQUJ5. Ehman circled it with a red pencil and wrote “Wow!” in the margin. The Wow! signal remains one of the most famous candidates for an alien radio message. By the way, if you're wondering what aliens might have meant by 6EQUJ5, the characters were just a nerdy way to describe the rise and fall of the signal's power. Remarkably, the signal had a radio frequency of 1,420MHz, which physicists Giuseppe Cocconi and Philip Morrison had proposed in…

On 2 November 2000, a US astronaut and two Russian cosmonauts became the first full-time crew of the International Space Station (ISS). Expedition 1's Bill Shepherd, Sergei Krikalev and Yuri Gidzenko spent four months bringing the station to life – and a new era dawned. Thus began a 25-year human presence in space. Fast forward to today and the ISS has hosted 290 people from 27 nations. Building, maintaining and operating this Earth-circling marvel – the brightest artificial object in the sky, larger than a football field – is our grandest engineering success and a testament to international partnerships at their best. Put in context, around a quarter of Earth's population alive today has never known a moment when humans were not in space. When Shepherd's crew arrived, the ISS…

24P/Schaumasse isn't the only comet of interest this month. Another brightening comet is C/2024 E1 (Wierzchoś), which can be found moving across the large form of Ophiuchus, the Serpen Bearer. This spring/summer constellation is still visible under dark skies in the early evening, low above the western horizon. Comet C/2024 E1 crosses Ophiuchus from a point southwest of Kappa (κ) Ophiuchi at the start of November, to end the month near Mu (μ) Ophiuchi. During this time, it brightens from mag. +11.7 on 1 November to +10.4 on 30 November, making it a viable small-telescope object. C/2024 E1 is predicted to brighten to around fifth magnitude around 20 January, but by then will have moved too far south to be seen from the UK. Keep an eye out for the…

Byrgius Type: Crater Size: 88km Longitude/latitude: 65.4° W, 24.7° S Age: Around 3.9 billion years Best time to see: Five days after first quarter (3 and 4 November) or four days after last quarter (17 and 18 November) Minimum equipment: 50mm telescope Crater Byrgius is located in a highland region roughly midway between dark-floored Grimaldi (222km) and Schickard (227km). Under high illumination, this 88km-diameter feature is best revealed by Byrgius A, an 18km crater with an impressively bright ray system emanating from it. The rays stand out very well under direct illumination, even against the bright surrounding highlands. Byrgius A sits on the eastern rim of Byrgius, its rays expanding out in all directions and completely covering Byrgius's floor. Byrgius A is an example of a classic, young crater. Its…

1. The Hyades The V-shaped Hyades open star cluster is next to mag. +1.0 Aldebaran (Alpha (α) Tauri), the reddish eye of the Bull, a foreground star that's not actually part of the cluster. At 153 lightyears distant, it's the nearest open cluster to Earth. In British folklore, the Hyades are the “8 for the April Rainers” in the counting song Green Grow the Rushes, O, referring to spring rains at their final dawn appearance. □ SEEN IT 2. NGC 1647 Just 3° northeast of Aldebaran is a delightful little open cluster, NGC 1647. It's often overlooked because of the presence of its more prominent neighbour. With 10x50 binoculars, you should be able to see eight or nine stars against a background glow a bit bigger than the apparent size…

I magine you're in a woodland, with sunlight filtering through the endless green canopy overhead. There's uniqueness everywhere. Some trees grow bolt upright, but others are wizened and twisted. Here the ground is clear, but over there it's riddled with brambles and thorns. Yet this individuality fades if you can climb a ridge and lift yourself above the canopy. Now your view is a constant sea of green for as far as the eye can see. The forest is both regular and directionless. Most cosmologists believe that the Universe works in the same way. At small scales, there are individual quirks such as stars, planets and different types of galaxies. But zoom out far enough, to scales of hundreds of millions of lightyears, and it's like climbing that ridge: the…

The quality of your astro images isn't just down to your processing skills. Key is the relationship between your telescope's optics, your camera's imaging chip and your local atmospheric ‘seeing’ conditions. Locations with steep temperature gradients and turbulent air – such as urban areas – usually mean poor seeing conditions that distort starlight and blur images. While you can't do much to reduce poor seeing – short of opting to image higher-altitude targets – you can optimise your setup for your local environment by understanding your image scale and image sampling rate. Here's how to match your gear to the sky for sharper, more detailed results. Find your ideal scale Seeing conditions can be summarised as the ‘full width at half maximum’ (FWHM) of stars, and are measured in arcseconds.…

STEP 1 M44 is a large open cluster shining at a magnitude of +3.5 and with an apparent diameter approaching 1.2°. If you hope to capture the comet's motion across the entire cluster, the best way will be to image the whole of M44 in one go – but be aware that the comet may appear small and faint. STEP 4 This comet's passage across M44 is a great way to put your smart scope to good use if you have one, as it will be able to locate the cluster even with the Moon nearby. It may struggle after 10 November when the Moon is very near M44, especially if the sky is hazy. Find out your smart scope's field of view and compare it with the size of…

JAMES WEBB SPACE TELESCOPE AND HUBBLE SPACE TELESCOPE, 29 AUGUST 2025 The reddish, vertical bar in this image is the protoplanetary disc around a newborn star some 525 lightyears from Earth. Officially named (somewhat inelegantly) IRAS 04302+2247, this infant star is already being orbited by a disc of gas and dust that within just a few millennia may clump together and form planets. We're seeing this disc from edge-on, which is why it looks more like a bar in this picture. This also means the disc is blocking light from the star itself, enabling the faint glow of two reflection nebulae on either side to become visible. With its wing-like glow, it's easy to see why it's been nicknamed the Butterfly Star. Pointing the finger JAMES WEBB SPACE TELESCOPE, 4…

A giant gamma-ray burst (GRB) has been detected that has astronomers scratching their heads. GRBs are some of the most powerful explosions in the Universe and are thought to be produced by the catastrophic destruction of stars. But this new explosion, spotted a few billion lightyears outside our Galaxy and named GRB 250702B, was unlike any seen before, bringing this theory into question. “This event is unlike any other seen in 50 years of GRB observations,” says Antonio Martin-Carrillo of University College Dublin and co-lead author of the study. “GRBs are catastrophic events; they're expected to go off just once because the source that produced them does not survive the dramatic explosion. This event baffled us, not only because it showed repeated powerful activity, but also because it seemed to…

The JWST has discovered a brand-new resident of our Solar System: a tiny moon orbiting Uranus, thought to be a mere 10km (6 miles) wide. That means you could walk around it in just a few hours – provided you found a way to stick to its low-gravity surface, of course. “It's a small moon, but a significant discovery, which is something that even NASA's Voyager 2 spacecraft didn't see during its fly-by nearly 40 years ago,” says Maryame El Moutamid, who led the team that spotted it. The moon is in good company, as its discovery brings the number of moons orbiting the planet up to a grand total of 29. “No other planet has as many small inner moons as Uranus,” says Matthew Tiscareno of the SETI Institute…

Many people say to me: “Whenever I look at the stars, it makes me feel so small and insignificant; it scares me.” It's true – from one perspective, we are but a minute speck of dust on a tiny pebble, orbiting a dim star in a galaxy among billions, existing for half a blink of a cosmic eye. The problem is that this speck of dust easily gets very caught up in itself, always worried, but wanting to feel important. We worry about where our life is going, how to fix the broken toilet, whether to move house, what to cook for dinner tonight… the list goes on. The worries can get so all-consuming that we can't see out through the tangle of thoughts and emotions to see the bigger…

Since the pioneering work of radio astronomer Frank Drake in the early 1960s, many projects have searched for artificial radio signals from outer space. Over the decades, the sensitivity, bandwidth and computing power of SETI programmes has grown tremendously, but no one has yet received a call from ET. At present, the 42-dish Allen Telescope Array (ATA) in northern California, named after its main benefactor and Microsoft co-founder Paul Allen, is the only facility almost fully dedicated to the search for extraterrestrial intelligence. The Breakthrough Listen programme, funded by Israeli billionaire Yuri Milner, buys observing time at the 110-metre (360ft) Green Bank Telescope in West Virginia, USA, and the 64-metre (210ft) Murriyang Telescope in Parkes Observatory, New South Wales, Australia. In 2019, it detected a signal from the direction of…

BEST TIME TO SEE: Mid-November to mid-December Saturn underwent a ring plane crossing back in March of this year, an event which sadly occurred too close to the Sun to be seen clearly. However, the opportunity isn't quite over yet. Let's explain what a ring plane crossing is. During Saturn's 29.5-year orbit around the Sun, the Sun appears on Saturn's equatorial plane twice, at the Saturnian equinoxes. As Saturn is so far from Earth, we get a similar perspective as the Sun, and the planet appears edge-on to us too. Due to Earth's orbital position, we don't see Saturn edge-on at exactly the same time as the Sun does, but when we do, the 10–30-metre average thickness of the ring system means the famous rings disappear for a short period…

Uranus Best time to see: 21 November, 23:55 UT Altitude: 57° Location: Taurus Direction: South Features: Colour, subtle atmospheric bands, moons Recommended equipment: 200mm or larger Dim planet Uranus is extremely well placed for observation from the UK in November. It reaches opposition on the 21st and sits 4.5° south of the Pleiades open cluster, M45. This makes it easier to locate than in recent years. It's currently shining at mag. +5.6, which means it should definitely be possible to see with the naked eye from a dark-sky site. Turn to page 55 for this month's challenge, which is all about spotting Uranus without any visual aids. With optical assistance, Uranus's vast distance means you'll see little more than a tiny, green-hued disc through the eyepiece. In binoculars, it looks…

Comet 24P/Schaumasse, which passes in front of the Beehive Cluster this month (see page 47), was discovered by French astronomer Alexandre Schaumasse on 1 December 1911. It has an orbital period of 8.252 years and will next reach perihelion on 8 January 2026. At that time, it's expected to be around mag. +9.9 (suitable for small telescopes) and crossing from south of Melotte 111 into southern Boötes, where the bright Arcturus (Alpha (α) Boötis) provides a convenient way to locate it. The comet has a 2.6km nucleus and its orbit stretches from 1.21 AU at perihelion to 9.96 AU at aphelion. During its 1951–52 apparition, 24P/Schaumasse unexpectedly brightened to mag. +6. This, along with missed recoveries in 1968 and 1976, led to speculation that a destructive event caused the brightening.…

How many times have you heard that Uranus can be seen with the naked eye? We've certainly mentioned it often, but have you actually tried it? Chances are you haven't, and even if you have, you may have run into a number of common problems, such as not having a dark enough sky, not knowing exactly where to look or being fooled by nearby stars that have a similar brightness. All in all, it's enough to make you want to give up – but we'd urge you to keep at it, as Uranus is currently at mag. +5.6 and in a part of the sky that makes it relatively easy to locate. Let's start there: Uranus is now due south of the Pleiades open cluster, M45. It's easy to find,…

Although most conspiracy theories can be falsified, scientifically or logically, some by their very nature can't be disproved. This doesn't make them true, of course; it simply means there's no available counter-evidence. One example is the zoo hypothesis, often used to resolve the so-called Fermi paradox. Given that the Universe is so vast and old, and that Earth is presumably not the only place where life can develop, why is there no evidence of extraterrestrial intelligence? This is the Fermi paradox, often summed up with the question: “Where are they all?” The zoo hypothesis proposes that extraterrestrial civilisations have deliberately avoided contact with Earth, for any number of reasons, thus relegating us to an uncontaminated ‘laboratory’ or ‘zoo’. In other words, the entire Universe is conspiring to ignore us! Of…

Step 1 Look up your telescope's focal length or calculate it by multiplying its focal ratio (f/ number) by its aperture (in mm). Accurately determining the focal length is essential for precise pixel-scale calculation and matching a camera to your scope. Step 2 Check your camera's pixel size in microns (μm), usually listed in the manufacturer's technical specs. Different cameras, even from the same manufacturer, can have different pixel sizes, which will affect the image scale and sampling abilities. Step 3 Calculate the pixel scale using Nyquist's formula: (pixel size in μm ÷ focal length in mm) x 206.265. This gives the angular size of the sky that each pixel covers in arcseconds and determines how well your sensor samples the image from the telescope. Step 4 Now compare the…

There's a vast array of astronomy image-processing software on the market, often with high initial or monthly costs coupled with a steep learning curve. StarTools offers a full suite of easy-to-use functions that take a basic stacked image and transform it, for a reasonably modest one-off licence fee. A free trial period is available, so you can decide whether it works for you (though you can only save your final image once you've purchased the licence). All of the functions in StarTools are operated by sliders, with a live view shown in the main window, making it very simple to get to grips with if you're new to image processing. For this walkthrough, we'll use two key tools: High Dynamic Range (HDR) and noise reduction (NR) – powerful features that…

VITAL STATS Price £259 Optics 80mm achromatic refractor Focal length 400mm, f/5 Mount Manual altazimuth with slip clutch Extras Tripod, solar filter, 2x Barlow, 6mm and 20mm eyepieces, smartphone holder, compass Weight 4.3kg Supplier Bresser UK Tel 01342 837098 www.bresseruk.com Astronomy has always carried a certain mystique. For many, it feels like an intimidating hobby, steeped in technical jargon and reliant on complex equipment. The new Bresser PushTo AR-80/400 smart telescope sets out to dispel that reputation. Combining classic refractor optics with a manual mount and an app-based navigation system, it positions itself as a beginner's gateway to the cosmos. Over several evenings – and a daytime solar session – we put it through its paces. The scope arrived from Bresser UK in one tightly organised package. Setup was delightfully…

We've had a few false alarms before – including fossilised microbes and signs of carbon dioxide production in Martian rocks – but NASA has now cautiously suggested it's found signs that life once existed on Mars at the same time that it was emerging on Earth. Since 2021, the Perseverance rover has been exploring what's thought to be a dried-up lake in Jezero Crater, a site chosen for its potential to preserve ancient life, if it ever existed on the Red Planet. In July last year, near the mouth of an ancient river, it took samples from the Bright Angel formation, rocks marked with patterns nicknamed ‘leopard spots’ and ‘poppy seeds’. These samples contain minerals arranged in ways that, on Earth, are found in the byproducts of microbial activity. Put…

When we imagine planets, we usually picture them circling a fiery star like our Sun. But new evidence has now been found of a type of planetary system that instead forms around cold planets that float free through the cosmos. Using JWST's powerful infrared instruments, astronomers at the University of St Andrews in the UK have discovered dusty discs around a selection of these ‘rogue’ worlds. Spectroscopic analysis revealed that the planets, each 5–10 times the mass of Jupiter, have discs with the same composition as the protoplanetary discs found around young stars, from which planets typically coalesce. They also found silicate grains in the rogue worlds’ discs that show signs of crystallisation and growth – in other words, signs that tiny asteroids, the seeds of rocky, Earth-like planets, were…

If we want to explore the farthest reaches of our Solar System, current rocket speeds are just not up to scratch. Even with our fastest engines, it's a three-year round trip to Mars – and that's our closest neighbour. Stepping up to the plate to tackle this problem are scientists at Ohio State University. With NASA funding, they are developing a rocket which they say can cut the time it takes to get to the Red Planet by half. The key element to achieving this? Liquid uranium. Called the centrifugal nuclear thermal rocket (CNTR) system, instead of relying on chemical combustion or solid nuclear fuel rods to heat rocket propellant (like those used in engines tested at the beginning of the Space Race), the engine spins the uranium at very…

One of the most important features of extrasolar planets is whether they have an atmosphere or not. For astrobiology in particular, small, rocky planets blanketed with an atmosphere offer the best hope in the search for life beyond Earth. The two key factors affecting whether a planet can retain an atmosphere over billions of years are: its escape velocity, which affects how well its gravity is able to hold on to a gas envelope; and the cumulative amount of sunlight it has received from its star (instellation). High instellation, particularly of extreme X-rays, acts to strip away gas molecules. In an influential 2017 paper, Kevin Zahnle and David Catling plotted known exoplanets, as well as the planets and moons in our Solar System, on axes of escape velocity versus instellation.…

MESSAGE OF THE MONTH The magazine's recent alerts about opportunities to see Titan's shadow on Saturn (The Sky Guide, August and September) were fine incentives. The weather here in the northeastern USA was favourable for many of these. The sight of Titan just below and to the left of its shadow on 20 September was particularly gratifying. Here are two of my images taken following your guidance. The first (left) shows Saturn and its moons Rhea, Titan and Dione on 3 August at 0351 EDT, taken with a Celestron NexStar 6SE telescope and a ZWO ASI662MC camera with a 3x Barlow lens fitted. The second (right) shows the view on 20 September at 02:14 EDT, with Saturn and its moons Dione, Titan, Tethys and Rhea, taken with the same setup…

When comet 3I/ATLAS was discovered in July, on a one-way interstellar journey through our Solar System, Harvard astronomer Avi Loeb suggested it might be an alien spacecraft paying us a visit. Back in 2017, he made similar claims about the very first known interstellar object, the asteroid 1I/‘Oumuamua. In fact, despite their somewhat unusual properties, both celestial bodies appear to be completely natural, and most astronomers dismiss Loeb's speculative assertions. But what if he was right? What if we really did find a piece of alien hardware? “Proof of the existence of extra-terrestrial intelligence would be the most important discovery in human history,” says Andrew Siemion, principal investigator at the privately funded Breakthrough Listen programme. And while Breakthrough Listen uses radio telescopes around the world to search for possible interstellar…

Comet 24P/Schaumasse will appear to pass across the Beehive Cluster, M44, this month, offering an excellent opportunity to record this relatively faint object. On 1 November, it's expected to shine with an integrated magnitude of +14.3 – that's too dim for small scopes and a challenge for larger apertures. However, if you're set up for imaging, that brightness is well within reach. It's also worth attempting with a smart scope. There's a catch, though: the Moon will be big and bright in the sky not far from the comet's path. This is where the Beehive Cluster comes in. Its point light source stars will be able to withstand a bit of natural light pollution (moonlight) and should be easy to spot. Knowing where the comet will be passing – even…

Cetus, the large, sprawling constellation of autumn and early winter skies, is commonly referred to as a whale. Indeed, on charts its outline does resemble a west-facing whale – but this is misleading. The star marking the ‘tail’, Menkar (Alpha (α) Ceti), has a name that means ‘nostril’, while Diphda (Beta (β) Ceti), the supposed ‘mouth’, actually means ‘second frog’ (the ‘first frog’ being Fomalhaut, the brightest star in Piscis Austrinus). An earlier name for Diphda was Deneb Kaitos, meaning ‘whale's tail’, which seems more fitting… except it conflicts with the idea of the whale facing west. Diphda shines at mag. +2.0, making it brighter than Menkar's mag. +2.5. It's an orange giant of spectral type K0 III, located 96.3 lightyears from the Sun. The star is 17.5 times larger…

Your new telescope arrives and you plan to take it for a spin through the stars. But a smog of light sits low in the sky, washing away your views to distant galaxies – along with your astronomy dreams. Quickly you realise you need a quality dark-sky site. But how dark is dark? And how do we compare one location's sky to another? Enter the astronomer's friend: the Bortle scale. Amateur astronomer John E Bortle set out to create a sky-brightness scale that would be easily accessible to stargazers and scientists alike. Launched in 2001, it was quickly adopted by anyone curious about the darkness of their skies, and how theirs stacked up against others. Light pollution, even in small amounts, impacts our view of the cosmos. Sadly, 99 per…

Comet 24P/Schaumasse is a faint comet, but definitely within reach of amateur imagers. It's really well placed on 7–11 November, passing in front of the Beehive Cluster, M44 (read more on page 47). But there are two challenges. First, 24P is expected to be dim during November, shining at mag. +14.3 or so. That's manageable for deep-sky setups, but then there's the second problem: the Moon. During the comet's passage, the Moon lies west of M44 and will be just past a perigee full phase, meaning it'll be bigger and brighter than average. Ouch! Don't be put off though. Any attempt to image the comet offers good practice for later weeks, when 24P becomes brighter and the Moon moves out of the way. The fact that M44 is easy to…

What is 3I/ATLAS and what makes it so interesting? 3I/ATLAS is an interstellar object that was discovered passing through the Solar System by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey. During the survey, we built a simulation: the Ōtautahi– Oxford interstellar object population model. Among other things, this can tell us about the age of transiting bodies like 3I/ATLAS. I noticed that 3I/ATLAS was bobbing up and down on its orbit around the Milky Way, which was a lightbulb moment for me, because I knew that older stars also followed a similar pattern in their orbits. When we ran all the statistics and looked at the correlations, we found that 3I/ATLAS was probably over seven billion years old, about twice the age of our Solar System. Why have we…