Starlink over Belgium: lights in a row in the sky
One of the most reported sightings in recent years: a row of evenly spaced white points of light moving in a straight line across the sky. Almost certainly a Starlink train from SpaceX — and Sky Lens can confirm it from current orbital data.
SpaceX is building a mega-constellation of satellites to deliver global internet from low Earth orbit (LEO). The scale of this project is unprecedented in the history of spaceflight.
Mass launches
SpaceX launches batches of typically 20–60 satellites at once on a Falcon 9 or Starship. After launch they fly close together in formation at an initial altitude of ~340 km — this is the visible 'train'. They then climb to their operational altitude.
Operational altitude
After the first 1–4 weeks the satellites reach their operational altitude of ~550 km and spread along their orbit. At this altitude they are individually visible as fairly bright, steadily moving points — but no longer as a recognisable train.
Scale of the constellation
There are now more than 6,000 Starlink satellites in orbit. SpaceX has applied for approval for up to 42,000 satellites. At any given moment, dozens of Starlink satellites are above Belgium, but only a few are visible to the naked eye per pass.
Impact on the sky
Astronomers are concerned about the impact on astronomical observations. SpaceX is working on 'visorsats' — sun shades that reduce the brightness of the satellites. Brightness varies greatly by model and orientation.
The following characteristics together make a Starlink train uniquely recognisable. No other object in the sky shows the same combination.
Pattern
5–20 evenly spaced points of light in a straight row. The spacing is uniform — like a string of lights on a taut line. Aircraft always fly alone.
Movement
Moves in a perfectly straight line across the sky. No turns, no deviation. Typically travels from west to east or south-west to north-east, depending on the orbital inclination.
Speed
~7 km/s orbital speed — they move noticeably fast across the sky. A full pass from horizon to horizon takes 2–6 minutes depending on the maximum elevation angle above your location.
Light character
No flicker — steady, constant light. Brightness may vary as they rotate (orientation effect), but there is never a rhythmic strobe like aircraft.
Sound
Completely silent. If you see a row of lights moving steadily across the sky — that is a strong argument for satellites and against aircraft or drones.
Colour
Bright white. No colour change, no red or green. Stars low on the horizon do flicker red and blue (scintillation), but Starlink satellites are high enough to avoid this effect.
The visibility window is limited — you cannot simply see Starlink in the middle of the night. The geometry of the sun, earth and satellite must align.
Twilight required
Satellites are only visible when they themselves are in sunlight, but the earth beneath them is already dark. This gives a window of 30–90 minutes after sunset and 30–90 minutes before sunrise. During the day they are invisible due to ambient light; in the middle of the night they are in Earth's shadow.
Variable pass times
Exact pass times vary every day by location. A satellite that passes today at 21:04 will be visible tomorrow at 21:19 (the orbit shifts ~15 minutes per day). Sky Lens calculates this precisely for your coordinates.
Seasonal visibility
In summer, when nights are short, satellites are sometimes visible late in the evening because the sun has not yet dropped far enough below the horizon. In winter the window is earlier but shorter.
Cloud cover
Cloud cover blocks the view of satellites completely. Sky Lens also shows the cloud cover at the time of your observation so you know whether it was physically possible to see the satellite.
Sky Lens has real-time access to TLE orbital data (Two-Line Element sets) for more than 14,000 objects in Earth orbit, updated multiple times per day.
Orbital calculation
Sky Lens calculates the exact position of every known satellite at any given time via the Skyfield library. For Starlink, all 6,000+ active satellites are included in the calculation.
Position and angle
For your location and time, Sky Lens calculates which satellites were above the horizon, at what elevation angle, in which direction they were moving and how bright they were (based on distance and sunlight geometry).
Candidate list
If Starlink satellites match your description (direction, elevation, direction of movement, time), they appear at the top of the probability list — with the calculated elevation angle and direction as evidence.
Enter your location and time. Sky Lens calculates which Starlink satellites were flying above your location at that moment and gives you the exact elevation angle and direction.