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Artist's illustration of a blue, banded Jupiter-like world with swirling cloud features, seen against a dark star field with the Milky Way on the right.

Space science

Webb watched water clouds thin and thicken on the coldest known brown dwarf

WISE 0855 is the coldest brown dwarf anyone has found, at about 265 K (−8 °C), and it sits 2.28 parsecs (about 7.4 light-years) from the Sun. A team led by Brittany Miles of the University of Arizona’s Steward Observatory pointed JWST’s NIRSpec spectrograph at it for 11 hours, taking a spectrum every 15 minutes. As the object rotated, the spectra changed in two separate ways. High in the atmosphere, the team finds patchy water clouds whose thickness varies from one side to the other. Deeper down, carbon monoxide and phosphine rise and fall together, which the team reads as temperature changes in gas welling up from the interior. The paper, “Water Cloud and Chemical Modulations in the Coldest Brown Dwarf”, is on arXiv and listed as accepted to The Astronomical Journal. The University of Arizona announced it on 9 October. ...

The Pleiades star cluster in a colour survey photograph: a handful of bright blue-white stars wrapped in wispy blue reflection nebulosity against a black field scattered with fainter stars

Beginner stargazing

How to find the Pleiades, and what a star count says about your sky

Look east-northeast a couple of hours after dark this week and you’ll find a small, tight knot of blue-white stars climbing out of the horizon haze. Most people take it for a smudge the first time they see it, and some take it for the Little Dipper. That’s the Pleiades, the Seven Sisters, Messier 45, and from now until spring it’s the easiest star cluster in the sky. You need nothing but your eyes to find it. Once you have, it doubles as a dark-sky test: count how many stars you can pick out of the knot and you have a rough reading of how good your sky is that night. ...

Composite night photograph of the Orionid meteor shower: about a dozen thin meteor streaks cross a dark blue starry sky above a row of silhouetted pine trees and a pond, with the constellation Orion visible at upper left.

Celestial event

Orionids 2026: wait out the gibbous Moon, then watch Halley's meteors until dawn

The Orionid meteor shower peaks on the night of October 21–22, 2026, and this year the Moon decides when you go out. A waxing gibbous Moon, about 80% lit, hangs over the evening sky and doesn’t set until 02:55 local time in Cyprus (23:55 UT) on the peak morning. After that you get roughly two and a half hours of properly dark sky before dawn starts at 05:34. Those happen to be the hours when the Orionid radiant is highest anyway. Set an alarm for 03:00, look south, and expect around 10–12 meteors an hour from a dark site, fewer from a town. No equipment needed. ...

Telescope photograph of Mars and Jupiter close together on a black star field: Mars is a small orange point near the top, Jupiter a brighter blue-white point lower down with tiny dots of its moons beside it, both with four-pointed diffraction spikes.

Celestial event

Mars is closing on Jupiter: watch the gap shrink to 1.2° by November 16

Two bright planets are up before dawn right now, and the gap between them shrinks every morning for the next month. This morning Mars and Jupiter are 12.7° apart, a bit more than a fist held at arm’s length. By the morning of November 16 that gap is down to 1.19°, a little over two full-Moon widths. Closest approach is around 02:00 UT on the 16th, which is 04:00 in Cyprus, with both planets riding high in the south-east. You don’t need any equipment for this one. Pick a morning each week, note how far apart the two points are, and watch Mars catch up. Binoculars add Jupiter’s moons. Around the 16th, a small telescope at its lowest power can just about hold both planets in a single field. ...

Colour image of Phobos from NASA's HiRISE camera: a dark, lumpy, cratered moon with grooves across its surface and the large crater Stickney at lower right

Space news

JAXA's MMX heads for Phobos: what 10 grams of a Martian moon can settle

JAXA’s Martian Moons eXploration spacecraft, MMX, is scheduled to lift off on an H3 rocket from Tanegashima at 04:41:03 Japan time on 20 October 2026. That’s 19:41:03 UTC on Monday 19 October, or 22:41 here in Cyprus, where we’re still on summer time for one more week. If the weather or the rocket says no, there’s a backup period running to 7 November, with a separate launch time for each day (JAXA launch notice). The goal is to bring more than 10 grams of Phobos, the larger of Mars’ two moons, back to Earth in JAXA’s fiscal year 2031. ...

The Milky Way arching over the telescope domes of the Teide Observatory on the Izaña ridge in Tenerife, with Scorpius and Antares on the right and a faint glow of coastal light on the left horizon.

Astrotourism

Stargazing on Teide: how dark Tenerife's sky really is, and where to stand

Tenerife is the easiest high-altitude sky in Europe to get to: two international airports and a paved road up to the Teide cable car’s base station at 2,356 m. The catch is in the photometry. The professional observatory on the Izaña ridge measures its moonless zenith at 21.20 magnitudes per square arcsecond, half a magnitude brighter than La Palma’s Roque de los Muchachos, about 144 km to the west-northwest. Below I go through where that extra light comes from, which caldera viewpoints to use, what the guided tours cost, and what a winter trip to 28° north shows you that Cyprus can’t. ...

Diagonal white streaks left by more than 25 Starlink satellites crossing a Lowell Observatory telescope image of the NGC 5353/4 galaxy group, taken on 25 May 2019.

AI × astronomy

Satellite trails in 1 in 6 VST images: how neural networks find them

In 2023 the VLT Survey Telescope on Cerro Paranal recorded 1,246,048 CCD frames with its OmegaCAM imager. A team led by Elisabeth Rachith at EPFL ran all of them through a deep-learning streak detector, and their June 2026 preprint reports 25,335 streaks from satellites, rocket bodies and debris, with at least one in 16.9% of exposures. In the months checked by hand, about a fifth of the confirmed streaks matched nothing in the public satellite catalogue. Below: how these networks work, what the VST numbers say, and why a stack of backyard subs mostly doesn’t need one. ...

A line of evenly spaced Starlink satellites crossing a deep-blue twilight sky above the painted town hall on Tübingen's market square

Beginner stargazing

Plane, satellite or space station? How to identify a moving light in the night sky

A point of light is sliding across the sky, silently, and you want to know what it is. You can almost always answer that in about ten seconds with four checks. Look at whether it blinks, whether it moves in a dead-straight line at an even pace, whether it fades out in the middle of the sky, and how long it lasts. No gear needed, and a free pass-prediction website will confirm your guess afterwards. The key below is the one I use from my balcony in Nicosia; the sections after it explain each line. ...

Artist's illustration of a young star inside a broad blue ring of dusty debris, with a small planetary body crashing into a larger one in the foreground and glowing orange vapor streaming from the impact.

Space science

The dust of Moon-forming crashes: what Webb found in 21 extreme debris disks

The leading explanation for our Moon is a crash: something roughly the size of Mars hit the young Earth, and the debris that stayed in orbit pulled itself together into the Moon. Nobody was around to watch that, but a new study shows we can watch the same kind of event around other stars through the dust it leaves behind. Kate Su of the Space Science Institute in Boulder and nine co-authors combined JWST and Spitzer mid-infrared spectra of 21 “extreme debris disks”, rare systems where planet-sized bodies are colliding right now. The dust chemistry splits them in two. Silica-rich disks point to violent crashes between Mars-sized embryos, and they turn up only around stars younger than about 300 million years. Silica-poor disks point to Moon-sized impacts, and they also appear around much older stars. The paper is accepted in The Astrophysical Journal (preprint: arXiv:2607.06684), and NASA and ESA/Webb released it on 2026-10-01. ...

The original ZWO Seestar S50 smart telescope on its tripod, photographed from below against a clear blue daytime sky, its rounded optical tube raised above the Seestar-branded base, with treetops along the bottom edge of the frame.

Gear

Seestar S50 Pro vs the original S50: is the upgrade worth $999?

ZWO’s Seestar S50 Pro started shipping on September 1 and now lists at $999 (€999 in Europe) on ZWO’s product page, after an $899 launch price that ended on September 15. I’ve run the original S50 from my Bortle 7 balcony in Nicosia for most of a year, so the question I care about is narrow: if you already own an S50, what does $999 buy you? It buys the same light grasp and the same pixel scale, roughly 3.7 times the sky per frame, a 67% bigger battery, a wide-angle camera, and a main sensor nobody expected. For most S50 owners imaging from a city, I’d hold off. For a few, it fixes the exact thing that’s been annoying them. ...