Answers · 10 questions
Straight answers, no scrolling.
The questions people actually type into a search box, answered in two or three sentences. Time-dependent answers are computed for Beijing and say so.
What time does the sky get properly dark tonight?
From Beijing (39.90, 116.41), astronomical darkness runs from 18:55 to 05:07 local time — about 10.2 hours. "Properly dark" means the Sun is more than 18° below the horizon, which is when the sky background stops hiding faint objects.
more →Can I see the space station tonight?
Yes — the next visible pass over Beijing starts at 04:04 local time and peaks 13° above the horizon to the north. It rises in the north-west and disappears in the east-north-east, and lasts about 9 minutes.
more →Which planets can I see tonight?
From Beijing tonight the planets clearing 10° are Mars, Jupiter, Saturn. Mars is the highest at 60° to the south-east. Anything below 10° is usually lost behind buildings and haze, whatever the sky conditions.
more →What does NET mean on a launch schedule?
NET stands for "No Earlier Than" — the earliest moment the vehicle could launch given what is currently known. It is a floor, not an appointment: dates slip backwards far more often than forwards, and a launch scrubbed at T-30 seconds gets a new NET.
more →How fast does the ISS move?
About 7.66 km/s, or roughly 27,600 km/h — one orbit every 92 minutes, which is why it crosses the sky in four to six minutes and why the good passes shift a few minutes earlier each evening.
more →Why is a bright planet sometimes impossible to see?
Because visibility is a geometry question, not a brightness one. A planet below your local horizon is on the other side of the planet, and one low above the horizon is seen through several thicknesses of atmosphere that smear it into a wobbling blob.
more →What is the difference between civil, nautical and astronomical twilight?
They are defined by how far the Sun is below the horizon: 6°, 12° and 18°. Civil twilight ends when street lights matter, nautical when the sea horizon disappears, and astronomical when the sky background is finally dark enough for faint objects.
more →Do I need a telescope to see Saturn's rings?
Yes, but not a big one. Around 30× separates the rings from the planet, so a small 70-90 mm telescope on a steady mount is enough; binoculars will not resolve them. The mount matters more than the aperture at that price.
more →How accurate are satellite pass predictions?
Good to seconds for a day-old element set, and to a few minutes for a week-old one. We propagate the latest Celestrak TLE with SGP4 locally in your browser, so the table is as fresh as the element set and the page says when it was fetched.
more →When is the next rocket launch?
The next orbital launch on our board is GSLV Mk II | IRNSS-1L (NVS-03), NET 2026-10-30 18:21 UTC, from Satish Dhawan Space Centre Second Launch Pad. Launch times move; the board prints the age of its snapshot on every page so you can see how current that is.
more →The full picture
Sunset to sunrise on one axis, with the targets that clear the horizon.