How to Spot the ISS Tonight

The International Space Station is one of the brightest objects in the night sky — easy to see from a city sidewalk, no telescope required. This guide covers when to look, what you’ll actually see, and how to be certain it was the station.

By the WatchSat team · Reviewed August 24, 2026 · Sources: CelesTrak, NASA

Why you can see it at all

The ISS carries nothing designed to be seen from the ground. What you’re looking at is sunlight, bouncing off a structure the size of a football field — about 109 metres across — wrapped in solar arrays and polished radiators. It orbits 400–420 km overhead at 7.66 km/s, circling Earth once every 92–93 minutes, roughly fifteen and a half laps a day.

The catch is geometry: you need to be standing in darkness while the station, high above you, is still in sunlight. That combination only occurs near the edges of the day — which is why you can’t simply walk outside at midnight and expect to find it.

When to look — and why the timing is strict

Visible passes cluster in the one to two hours after sunset and before sunrise. Earlier than that, the sky is too bright for even the station to punch through; later, the ISS is flying inside Earth’s shadow, with no sunlight left to reflect. One pleasant exception: at higher latitudes around midsummer, the shadow geometry flattens out and the station can stay sunlit all night, giving four or five visible passes between dusk and dawn.

Passes also come in streaks. The station’s orbital plane slowly precesses relative to your local twilight, so you get a run of several promising evenings, then a couple of weeks with nothing worth setting an alarm for. That is normal — check back.

How bright is bright

On the best passes the ISS reaches roughly magnitude −4, rivalling Venus and outshining every star. Even a mediocre pass at −2 beats Sirius, the brightest star in the sky. Brightness like that cuts through suburban light pollution and a fair amount of urban glow, which makes the station one of the very few spaceflight sights available from a downtown street.

Reading a pass prediction

A prediction boils down to four things: when the station appears, from which compass direction, how high it climbs, and how long it stays in view. Max elevation is the number to check first — the peak height above the horizon in degrees, where 90° is straight overhead and a clenched fist at arm’s length spans about 10°. Passes peaking above 40° are the memorable ones; below about 20°, the station skims rooftops and haze. For exact times computed for your own location — rise time, direction, peak elevation, and duration over the next five days — use the ISS pass predictions here on WatchSat. They are calculated on your device from the current orbit, and your location never leaves it.

What it looks like

A single, steady, white-to-gold point of light, gliding — not streaking — across the sky. It takes two to seven minutes to cross, about six for a high pass, and always travels on a west-to-east diagonal: the orbit is prograde, so it may appear from the southwest, west, or northwest, but it never moves westward. It also brightens toward the top of the pass. Overhead, it is about 420 km away; near the horizon you are looking through more than 1,500 km of slant range and far more atmosphere.

Plane, Starlink, or station?

Aircraft give themselves away: red and green navigation lights, white strobes blinking every second or so, and — at any distance where a plane looks that bright — audible engines. The ISS never blinks, makes no sound, and holds a perfectly steady speed along a perfectly straight track. Other satellites share that steady silence but are far fainter, most of them near the edge of naked-eye visibility. The one genuine look-alike is a freshly launched batch of Starlink satellites, which crosses the sky as a line of lights in single file rather than a lone point. If that is what you saw, the Starlink train tracker will confirm it.

Why it vanishes in the middle of the sky

On many evening passes the station fades out partway across, sometimes reddening for a few seconds first. Nothing is wrong — it has flown into Earth’s shadow. From the crew’s perspective, that moment is sunset, and the reddening is the same physics as yours: the last sunlight reaching the station is filtered through the atmosphere below. Morning passes run the film backwards, with the ISS appearing out of nowhere in mid-sky as it climbs into sunrise.

Photographing a pass

A pass photographs surprisingly well. Put a camera on a tripod, use your widest lens, focus manually on a bright star, and expose for 10–30 seconds at f/2.8–f/4 and ISO 400–1600 — the station draws a clean, bright streak. For the full horizon-to-horizon arc, shoot continuous back-to-back exposures and stack them afterwards. A recent phone in night mode, propped on a wall for its longest exposure, produces a respectable streak too.

How much to trust the predictions

For the next several days, pass times computed from fresh orbital data are good to within a few seconds — tighter than your ability to be outside on time. Beyond a week they can drift by minutes: atmospheric drag varies with solar activity, and the station periodically fires thrusters to reboost the kilometre or two of altitude it loses to drag each month, which shifts the schedule. The honest practice — and what WatchSat does — is to recompute from the latest published orbit every time you look, and to check once more on the day you plan to watch.

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