The Journal · Category
How to actually see it: binoculars and telescopes, technique, dark skies and astrotourism, phone astrophotography — and what each Bortle class really lets you observe from where you live.
Featured · Observing
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
Observing
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
Observing
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
Observing
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