Right outsideSky
How to spot satellites crossing the sky after dusk
When: All year
Satellites, including the International Space Station, show up as steady points of light crossing the sky in the hours after sunset and before sunrise. They have no lights of their own; you are seeing sunlight bouncing off them while the ground below is already dark.
Why this time of year
On clear evenings all year: about an hour after sunset the sky is dark enough to see them, but satellites overhead are high enough to still be in sunlight.
How to notice it
- On a clear evening, go outside about an hour after sunset (or about an hour before sunrise) and find a spot with a wide view of the sky, away from bright lights already on.
- Give your eyes a few minutes to adjust, then scan slowly for a 'star' that is moving.
- Check that it moves smoothly in a straight line without blinking: blinking lights usually mean a plane.
- Follow it for a few minutes. It may vanish partway across the sky - that is the moment it slides into Earth's shadow.
Try this with kids: Can you find a star that is moving? Keep your eye on it and shout when it disappears!
Good to know: Earth's shadow: the night side of the planet, which stretches out into space, so a satellite flying into it stops catching sunlight.
Safety
- Watch from a yard, field, or other spot off the road, and use a brief flashlight to get there and back.
Sources
- nasa.govPRIMARY (NASA). ISS sightings happen near sunrise or sunset because sunlight reflects off it against a darker sky. It looks like a plane or bright star but 'does not have flashing lights or change direction'. Quotes: 'All International Space Station sightings will occur within a few hours before or after sunrise or sunset.' / 'This is the optimum viewing period as the Sun reflects off the space station and contrasts against the darker sky.' / 'except it does not have flashing lights or change direction.'
- nasa.govPRIMARY (NASA FAQ). Not visible by day ('the space station is not bright enough to see during the day'). Best in twilight or at night. A pass can be cut short because 'the station is quickly moving into (or out of) the Earth's dark shadow', so 'a full pass across the sky cannot be observed'. 'Viewing opportunities can range from one a month to several a week', with no seasonal limit stated.
- asc-csa.gc.caPRIMARY (Canadian Space Agency, modified 2025-07-30). 'To the naked eye, the Space Station looks like a big white dot that moves quickly across the sky without changing direction, unlike aircraft.' It can be seen 'in urban areas even through all the light pollution'. Supports the plane distinction and that suburban viewing works.
- lompocrecord.comSECONDARY HOST of an expert column by Steven A. Ackerman and Jonathan Martin, professors in UW-Madison's Dept. of Atmospheric and Oceanic Sciences. Covers satellites in general, not just the ISS: 'Satellites do not have their own lights'. They are high enough that 'while you are in the darkness of night... the sun can still shine on the satellite'. 'steadily moving across the sky for a few minutes'. 'If the lights are blinking, you probably are seeing a plane'. 'will fly into the Earth's shadow and then will suddenly disappear from view.'
- skymaps.comSECONDARY (The Evening Sky Map / Skymaps.com, Kym Thalassoudis, copyright 2000-2012; an astronomy publisher, not a university). 'Satellites are best seen about an hour after sunset or before sunrise.' Low-orbit satellites are not visible late at night because Earth's shadow blocks the sunlight. 'Satellites often appear as a steady point of light and require a few minutes to travel across the sky.' 'They will disappear from view when in the Earth's shadow.' It also notes exceptions: tumbling rocket bodies flash, and Iridium satellites flare.
Checked against these sources on October 23, 2026.