The Journal

Sky guides & notebooks

Everything to observe better: when to look, where to go, what to seek.

La Lune visible en plein jour dans un ciel bleu limpide : le décor exact de l'occultation de Vénus du 14 septembre 2026.

Featured · Events

On 14 September the Moon Wipes Venus From a Daytime Sky

On Monday 14 September around midday, a 12 % crescent Moon will pass in front of Venus, magnitude -4.75, under a Sun standing 40 degrees high. From Paris the planet vanishes at 11:26 and re-emerges at 12:34; from London the Moon rises with Venus already hidden. The disappearance itself takes a minute and a half: Venus is a disc, not a point. City-by-city times, and the method for seeing a planet in daylight.

September 11, 2026

La galaxie d'Andromède, M31, photographiée au téléobjectif : le disque incliné, le noyau brillant et ses deux galaxies compagnes.

Atlas

The Andromeda Galaxy Is a Naked-Eye Object, if You Know Where to Rest Your Gaze

At 2.5 million light-years, M31 is the most distant thing the unaided eye catches without strain. It spans three degrees, six full Moons laid end to end, climbs to 82 degrees above Paris, and the moonless window runs from 5 to 17 September. The exact star-hop, and what your own sky will let through.

September 8, 2026

Un crépuscule calme et dégagé, la lumière déclinante sur l'horizon : l'heure où le ciel de septembre commence son programme.

Tonight

The September Sky: Venus Blazing, a Daytime Occultation and the Harvest Moon

Venus peaks at magnitude -4.8, yet its lead over the Sun melts from 61 minutes to 15 in a single month. In between, the Moon will hide it in broad daylight on the 14th, the equinox falls on the 23rd, and the full Moon of the 26th will rise barely later each evening. The month's programme, computed for Western Europe.

September 3, 2026

Composite photographique de plusieurs phases d'une éclipse de Lune : deux disques entièrement cuivrés par l'ombre de la Terre, puis un croissant gris resté éclairé par le Soleil.

Events

Lunar Eclipse Tomorrow Morning: Tonight's Checklist

Maximum is at 05:12 from London, with the Moon 8.0° above the western horizon. Everything depends on a clear horizon and an alarm set for 03:15. Here is what to do tonight, while it is still light.

August 27, 2026

Une Lune gibbeuse photographiée au télescope : le long de la ligne d'ombre, les cratères sortent en relief sous la lumière rasante, tandis que la partie pleinement éclairée paraît plate.

Observing

Why the Full Moon Is the Worst Night to Look at the Moon

Tonight, shadows on the Moon are seven times as long as the relief that casts them. On 27 August they will be a tenth of it. A factor of seventy in seven nights, and it comes down to a single angle: the Sun's height above the lunar ground. Here is the arithmetic, evening by evening.

August 20, 2026

La Voie lactée d'été dressée au zénith derrière une ligne de sapins en silhouette, dans un ciel bleu nuit saturé d'étoiles.

Atlas

The Summer Triangle: What Its Three Sides Actually Measure

Three stars everyone points at in summer, and whose dimensions nobody ever gives. We measured them in the catalogue the app runs on: 23.85 degrees, 34.20 and 38.01. The Triangle is nowhere near equilateral, it covers one hundredth of the whole sky, and it holds two entire constellations.

August 19, 2026

Une Lune presque pleine, basse dans un ciel crépusculaire rose et bleu, au-dessus de parcs à huîtres découverts par la marée et d'un horizon marin entièrement dégagé.

Events

The 28 August Lunar Eclipse: Western Europe Will Miss Half of It

The Earth's shadow will cover 96.6 % of the disc. But from Western Europe the Moon sets before the eclipse ends, seven degrees above the horizon, in a sky already turning grey. From the Caribbean and North America the whole thing happens high overhead in full darkness. Here are the times, the altitudes, and where you actually want to be.

August 19, 2026

Série d'images de Saturne prises par le télescope spatial Hubble entre 1996 et 2000, montrant l'ouverture progressive des anneaux au fil de l'orbite de 29 ans de la planète.

Atlas

Saturn Returns to the Evening Sky, Its Rings Reopened to 8.9 Degrees

Tonight it rises at 22:44, and it will gain twenty minutes every week. More to the point, its rings are open again: edge-on and all but gone in March 2025, they now stand at 8.9 degrees. Here is the season's timetable up to the 4 October opposition, and what instrument it takes.

August 17, 2026

La Voie lactée dressée au-dessus de l'horizon désertique de la Vallée de la Mort, dans l'un des ciels les plus noirs du sud-ouest américain.

Observing

The Milky Way From Western Europe: 12 Degrees Up, and One Hour to See It

Mid-August is the best stretch of the year for the core of our galaxy. It is also the moment to say what nobody says: from Paris it culminates at 12.2 degrees, and it culminates in full twilight. Here is the real window, latitude by latitude, and what the thickness of air takes from you on the way.

August 16, 2026

Un fin croissant de Lune et le point brillant de Vénus dans les dernières couleurs du crépuscule.

Tonight

Tonight a Crescent Moon Slips Below Venus, With Earthshine at Its Best

Between 21:10 and 21:55, low in the west-south-west, a crescent lit to 11.9 % passes within seven degrees of Venus. It is also the best evening this month to see the dark limb of the Moon lit by the Earth. Here are the two quarter-hours that matter, and the arithmetic of what is doing the lighting.

August 15, 2026

Le dégradé de l'aube au ras d'un horizon marin entièrement dégagé, du bleu nuit à l'orange, sans le moindre relief.

Events

Mercury and Jupiter Meet on 15 August: the Tightest Conjunction of the Half-Year

Tomorrow morning the two planets will fit inside a circle one and a half times the width of the full Moon. They will also be four degrees above the horizon in an already brightening dawn. Here is the honest arithmetic: the hour, the altitude, the azimuth, and why half of you will see nothing.

August 14, 2026

Une traînée de météore traverse un ciel d'été piqué d'étoiles, au-dessus d'une ligne de pins en silhouette.

Events

The Perseids After the Peak: Six Nights That Still Work

The maximum fell last night. The stream itself stays active until 24 August. We computed, night by night, the radiant's altitude, the window of genuinely dark sky and what the Moon leaves of it. Six useful nights remain, and one date on which the door shuts.

August 13, 2026

La Station spatiale internationale, ses huit panneaux solaires déployés de part et d'autre de la poutre centrale, sur fond de ciel noir.

Observing

How to Spot the Space Station From Your Own Garden in August 2026

There is nothing to buy and nothing to set up: the International Space Station is visible to the naked eye, and often brighter than the brightest star. You just have to know when. The answer depends on three things at once, and it changes every day.

August 12, 2026

The same field of sky rendered at each site's limiting magnitude: 17 stars from central Paris at Bortle 9, against 649 from the Haute-Provence Observatory at Bortle 4.

Observing

The Bortle Scale: How Many Stars Does Your Sky Actually Let You See?

Between central Paris and the Millevaches plateau there is not «a few more stars». There is a factor of thirty. Here is what the satellite atlas built into SkyChart computes for twenty real locations, and what it cannot tell you.

August 12, 2026

Le Soleil partiellement éclipsé : un croissant blanc mordu par la Lune, dans un ciel rouge de fin de journée.

Events

The 12 August 2026 Eclipse, Then the Perseids: the Darkest Night of the Decade

On the same evening, western Europe will watch the Sun set as a crescent, then the best meteor shower of the year fall through a moonless sky. That is no coincidence: it is the same Moon doing both.

August 12, 2026