Johannesburg 约翰内斯堡

We track three objects bright enough to be worth going outside for: the 空间站, 中国's 天宫 station and the 哈勃 Space Telescope. Each orbits at roughly 7.5 km/s and comes round every 90–95 minutes, but a pass only counts as visible when the object is sunlit while your sky is dark — which is why they cluster in the two hours after sunset and before sunrise.

Elevation is the angle above your horizon. 10° is easy to spot if you know where to look; 45° is unmistakable — brighter than any star, moving like an aircraft that makes no sound. The last column tells you where to look first and where it will disappear.

哈勃 is far fainter than the two stations: treat it as a dark-sky target for people who already know the sky, not a first sighting.

Positions from SGP4 propagation of the current Celestrak TLEs, checked against your coordinates; accuracy a few kilometres, which for “is it over my head” is plenty. A stale TLE drifts by seconds, not by orbits.