When is the ISS visible?

The ISS is visible during twilight — shortly after sunset or before sunrise — when the station is in sunlight but the ground is in shadow. Passes last 1-6 minutes. Check NASA's Spot the Station or Heavens-Above for pass predictions specific to your location.

What camera settings should I use for the ISS?

For ISS trail shots, use a wide lens (14-24mm), f/2.8-4, ISO 400-800, and 15-30 second exposures. For detailed ISS photography through a telescope, use a very fast shutter (1/1000s-1/2000s) to freeze the rapid movement, the widest aperture available, and a moderate ISO (typically 400-1600, 800-3200 from dark sites). The ISS is sunlit and very bright — metering at roughly EV 12 — so it does NOT need extreme ISO. If your calculator suggests a tiny ISO it is because the freezing shutter is already very fast at a wide aperture; for telescopes at f/8-f/10 the ISO rises into the hundreds.

How fast does the ISS move across the sky?

The ISS orbits at about 28,000 km/h and appears to cross the sky at roughly 0.5-1° per second when overhead. A high overhead pass crosses from horizon to horizon in about 6 minutes; a low grazing pass lasts only about 2 minutes. It is the third brightest object in the sky after the Sun and Moon.

Can I photograph detail on the ISS?

Yes, with a telescope (1000mm+) and video capture at high frame rates, you can resolve the solar panels and modules. Directly overhead at about 416 km the ISS subtends roughly 0.9 arcminutes (about 54 arcseconds), rising to nearly 1 arcminute (60-63 arcseconds) on the very closest passes; on lower, more distant passes it shrinks well below that. Lucky imaging techniques (stacking the best video frames) produce the sharpest results.

ISS Pass Calculator — Plan ISS Photography Settings

Estimate camera settings for photographing the International Space Station during visible passes.

Max Elevation

Peak height above the horizon (90° = straight overhead). Higher passes are faster, brighter and last longer — overhead ~6 min, low ~2 min.

Focal Length

A long lens or telescope (600mm+, ideally 1000mm+) is needed to resolve ISS structure; short lenses only show a moving point of light.

Aperture (f-number)

Use the widest aperture (lowest f-number) for the brightest, fastest exposure. Telescopes are often f/8-f/10, which raises the suggested ISO.

How We Calculate This

The ISS orbits at approximately 416 km altitude and crosses the sky at up to 1° per second during overhead passes.

Angular speed ≈ 0.3 + 0.7 × sin(elevation) degrees/second

To freeze the ISS motion on the sensor, the maximum shutter time is set so the apparent trail stays under about 10 µm (~2 pixels): max shutter ≈ 0.01 mm ÷ (angular speed in rad/s × focal length).

The suggested ISO uses the standard exposure relation ISO = 100 × N² ÷ (t × 2^EV100), where the sunlit ISS meters at roughly EV 12 at ISO 100 (back-solved from documented real settings — ISO 1600 at f/6.3 and 1/1600s). Because the freezing shutter is already very fast at a wide aperture, the ISS rarely needs a high ISO; ISO climbs into the hundreds only at small telescope apertures (f/8-f/10).

Pass duration is estimated from the maximum elevation — a high overhead pass lasts about 6 minutes, a low grazing pass about 2 minutes — and the ISS angular size is derived from the slant range implied by that elevation.

For wide-field trail shots, longer exposures are used intentionally to capture the ISS path as a bright streak across the sky.

Frequently Asked Questions

Related Calculators

500 Rule Calculator

Calculate the maximum shutter speed for sharp stars using the 500 Rule. Enter focal length and crop factor for instant results. Free online astrophotography calculator.

NPF Rule Calculator

Calculate precise maximum exposure time using the NPF Rule for pin-sharp stars. More accurate than the 500 Rule for high-resolution sensors. Free calculator.

Star Trail Calculator

Plan star trail photography sessions with exposure count, interval timing and total duration. Calculate trail length for stunning circular star images. Free calculator.

Moon Phase Calculator

Calculate moon illumination percentage and phase for any date. Plan astrophotography shoots around moonless nights for dark skies. Free online calculator.

Milky Way Position Calculator

Estimate Milky Way galactic core visibility based on your date and location. Plan shoots during peak visibility windows for best results. Free calculator.

Last updated: February 2026

All calculations are estimates based on standard optical and photographic formulas. Results may vary with specific equipment.