Week in Space Data, every Friday.
On the night of Saturday 26 September 2026, the ISS is not visible from Johannesburg, and no visible pass is predicted in the next 3 days.
Gauteng, South Africa: 26.20°S, 28.05°E (city centre). Recomputed every 15 minutes. Nothing on this page is sponsored.
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No visible ISS pass here in the next few days that we can time to the minute. The station's track drifts, so check back in a day or two.
5:12 AM: it comes into view low in the northwest (its highest point while you can see it), then drops below 10° in the north-northwest at 5:13 AM.
Full Moon, 100% lit
Up all night; sets Sun 27 Sep at .
At dusk it is 5° up in the east. A bright Moon washes out faint stars and Hubble; the ISS and planets still show.
Last quarter: Sat 3 Oct at
Venus magnitude −4.8
Up from to ; highest while dark (28°) in the west at .
Sunset . Dark enough for the ISS from . Fully dark to . Sunrise . Times are GMT+2 unless you switch to UTC.
Satellite passes: CelesTrak orbital elements (we download them at most every 6 hours) propagated with SGP4; checked against Heavens-Above for 31 visible ISS passes over six cities (26 to 29 September 2026), start, highest point and end agreed within 5 seconds (usually 1 to 3) and height within half a degree, except that our darkness rule can start a twilight pass a few minutes later than Heavens-Above does. Times drift by up to a minute or two when elements are several days old or after the station changes its orbit, so we time passes only a few days ahead. A pass counts as visible when, at some point 10° or more above your horizon, the Sun is at least 6° below your horizon and the satellite is in sunlight; times and heights describe that visible part, and brightness is estimated from distance and sunlight angle. Moon and planets: computed with astronomy-engine. Launches: times to the minute only, within 400 km of the pad. Aurora: NOAA SWPC Kp and storm forecast, with an approximate geomagnetic latitude. Newest elements: epoch 2026-09-26 11:47 UTC. Computed 3:38 AM GMT+2.
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A good ISS pass reaches magnitude −2 to −4, brighter than any star; at its best only the Moon and Venus outshine it. A low or distant pass can be as faint as magnitude 0. It is a steady white point that does not blink and makes no sound. Tiangong is a step dimmer (about −1 to −3 on a high pass) and Hubble is a faint, steady star (about +1.5 to +2.5) that wants a dark sky. We estimate the brightness of each pass from its distance and the angle of sunlight on it, the method Heavens-Above uses, and our figures land within about half a magnitude of theirs.
A satellite is visible only while it is in sunlight and you are in darkness. When it flies into Earth's shadow it fades out over a few seconds, often still high in the sky. That is not cloud: it is orbital sunset. We show where and when each pass fades.
The ISS orbits at 51.6° inclination and its ground track drifts west about 22° each orbit, so it overflies Johannesburg in runs of a week or two, then swings away for a similar stretch. Even when it does pass over, the Sun has to line up so the station is lit while your sky is dark. On nights with none, this page gives the next visible pass when there is one in the next three days; further out, pass times drift too much to print.
They are computed for Johannesburg's coordinates with astronomy-engine, an open-source ephemeris checked against NASA JPL data to about an arcminute, so rise and set times are good to about a minute. A planet is listed when it is at least 10° above the horizon while the Sun is more than 6° below it.
Drops low
north-northwest, 10° up
Jupiter magnitude −1.9
Up from to ; highest while dark (22°) in the east-northeast at .
Mercury magnitude −0.1
Up from to ; highest while dark (15°) in the west at .
Saturn magnitude +0.2
Up from to ; highest while dark (62°) in the north at .
Mars magnitude +1.1
Up from to ; highest while dark (31°) in the northeast at .