Satellite Visibility Calculator
Satellites shine by reflected sunlight, so they show up only when your sky is dark but they are still lit. This works out those windows for your city and date.
Satellite visibility
When a satellite can be seen from your sky, and how long a pass can last.
Height above the ground.
Sets how far north and south it travels.
10° clears most trees and buildings.
North positive, south negative.
East positive, west negative.
Pakistan Standard Time is UTC+5, with no daylight saving.
Choose a date to see when satellites can be seen.
How this is calculated
- 1
Orbital period and speed
From Kepler's third law, T = 2π √(a³ / GM), where a is the Earth's radius plus the altitude and GM = 398,600.4418 km³/s². The circular orbital speed is √(GM / a).
- 2
Footprint and pass length
The Earth central angle over which the satellite stays above the minimum elevation is λ = arccos(R cos el / (R + h)) − el. The longest pass is 2λ / 360 of an orbit, ignoring the Earth's rotation.
- 3
When it is still sunlit
A satellite overhead stays in sunlight until the Sun is arccos(R / (R + h)) below your horizon, about 20° for the ISS.
- 4
The viewing windows
Using the same solar maths as the Solar Position Calculator, the evening window runs from when the Sun is 6° below the horizon until it reaches that depth. The morning window is the mirror image before dawn.
Frequently asked questions
Can you see the ISS from Pakistan?
Yes. The ISS orbits at 51.6° inclination, so it passes over the whole of Pakistan, often several times a week in the evening or morning windows. Exact pass times come from tracking apps that use its current orbit.
Why can satellites only be seen after sunset or before sunrise?
They give off no light of their own. You need a dark sky to see them, but they must still be high enough to catch sunlight, which only happens in the hours around dusk and dawn.
How long does a satellite pass last?
For the ISS, a pass from 10° above one horizon to 10° above the other lasts at most about six and a half minutes. Most passes are shorter because they do not go straight overhead.
Can I see Hubble from Pakistan?
Yes, though from most of the country it stays in the southern sky. Hubble's orbit is inclined at 28.5°, so it never passes overhead north of that latitude, and from Islamabad it climbs no higher than about 40°.