How we calculate launch visibility
We tell you whether a rocket launch is visible from your exact location, where to look in the sky, and how long after liftoff it climbs into view. This page explains how — the geometry, the lighting model, the data sources, and the limits of what we can predict.
The core question
A rocket lifts off below your horizon and climbs downrange. Whether you can see it from where you are depends on four things: how far the pad is from you, how steeply the rocket gains altitude, how the line of sight bends around the curve of the Earth, and how much sunlight reaches the exhaust plume against the sky behind it.
Distance and bearing
For every launch we know the pad's latitude and longitude. From the location you enter, we compute the great-circle distance to the pad (the actual shortest path over the Earth's surface) and the initial compass bearing from you to the pad. The bearing is what we mean by "look toward the northeast" — it's the direction you face from your starting point along the great circle.
Will it actually climb above your horizon?
The trajectory model takes the rocket's typical ascent — a vertical kick followed by a pitch toward its target orbit — and projects the rocket's altitude and downrange position second-by-second after liftoff. At each second we check whether a straight line from you to the rocket is unblocked by the Earth's curvature. If it is, the rocket has cleared your horizon, and we record the time and the elevation angle.
For a viewer 200 miles from the pad, the rocket typically clears the horizon four to six minutes after liftoff. Closer than that and it's visible almost immediately; farther and it can take much longer — or not climb high enough at all.
Day, twilight, and night
Lighting transforms what you can see, dramatically. We compute the sun's elevation at the launch time and at your location to label every launch as day, twilight, or night:
- Daytime launches show up as a moving contrail and a bright spark — easy nearby, hard at distance.
- Night launches read as a fast-moving star with a flaring plume at stage separation.
- Twilight launches are the showstopper: the sky is dark but sunlight still catches the exhaust high above you, producing a fanning, glowing plume visible for hundreds of miles.
The five visibility tiers
We classify each launch into one of five tiers based on the closest the rocket gets to you (slant range) and the lighting at liftoff. The thresholds in miles:
| Tier | Day | Night | Twilight |
|---|---|---|---|
| Excellent — prime view | ≤ 90 mi | ≤ 150 mi | ≤ 230 mi |
| Good — clearly visible | ≤ 220 mi | ≤ 360 mi | ≤ 600 mi |
| Fair — low on the horizon | ≤ 360 mi | ≤ 560 mi | ≤ 1,050 mi |
| Marginal — hard to spot | ≤ 480 mi | ≤ 780 mi | ≤ 1,600 mi |
| Not visible | Past those distances, or the rocket never climbs more than ~1.5° above your horizon. | ||
A pass that only skims the horizon (peak elevation under 5°) is downgraded one tier — terrain and atmospheric haze hide low-angle passes in practice.
Weather overlay
Visibility geometry tells you what's possible; weather tells you what's likely. For each launch we pull the latest hourly forecast for the pad and the viewer location from Open-Meteo — cloud cover, visibility, precipitation, and wind — and classify the sky as clear, partly cloudy, or cloudy at liftoff. The cardinal direction word ("look east-northeast") and the visibility tier are free for everyone; the precise compass bearing in degrees, the minute-by-minute viewing timeline, and the launch-time weather forecast are Pro features in the app.
Data sources & refresh
- Launch schedule, pad coordinates, status, and mission data: TheSpaceDevs Launch Library 2.
- Weather: Open-Meteo hourly forecasts.
- The site rebuilds daily; the live finder fetches the latest schedule on every visit (with a short cache to keep loads fast).
Known limitations
- Terrain. We treat the Earth as smooth and the viewer at sea-level horizon. Mountains, buildings, or trees on the line of sight will block a launch we'd otherwise mark visible. Always have an open horizon in the direction we name.
- Light pollution. A "Marginal" night launch from a downtown is much harder to spot than from a dark site at the same distance. Our tiers don't model city lights.
- Trajectory variance. Each rocket flies a slightly different ascent. We use a representative orbital-rocket profile; specific missions (e.g. polar launches, Starship's flight test profile) can differ enough to shift the timeline by a minute or two.
- Weather only at liftoff. Cloud cover at liftoff matters most, but a fast-moving cloud bank can hide a launch you'd otherwise see — and clear it just as easily.
Questions or corrections? Email hello@looktospace.com.