How to Read a Rocket Launch Visibility Map
A rocket launch visibility map tells you two things: whether a launch will be above your horizon, and which direction to look. The underlying geometry is straightforward. A rocket gains altitude very quickly after liftoff, and once it is high enough, it is in line of sight for observers far away — the way a mountain peak is visible from across a plain. Understanding the numbers on a visibility display helps you get outside at the right time and face the right direction.
Compass Bearing: Which Way to Face
Compass bearing is the angle from true north, measured clockwise, that points from your location toward the launch site. A bearing of 0 degrees is due north; 90 degrees is due east; 180 degrees is due south; 270 degrees is due west. If LookToSpace shows a bearing of 95 degrees for your location, face slightly south of due east and that is where the rocket will rise.
The bearing does not change as the rocket ascends. The launch site is fixed on the ground, so you always look in the same compass direction. The rocket rises upward from that bearing rather than moving laterally across the sky, at least for the first few minutes. As it gains altitude and begins its downrange flight, it may slowly drift in compass direction, but the initial bearing is the most important number for getting oriented.
Elevation Angle: How High Up to Look
Elevation angle describes how far above the horizon the rocket is or will be at a given moment. Zero degrees is the horizon; 90 degrees is directly overhead. At launch, from a distant location, the rocket is at zero elevation — it is just rising above the horizon. As it climbs, the elevation angle increases slowly, then peaks when the rocket is at its highest apparent position before it moves downrange and the angle decreases again.
From 50 miles away, a Falcon 9 may reach a peak elevation angle of 30 to 40 degrees, which is well up into the sky. From 200 miles away, peak elevation may be only 10 to 15 degrees, meaning the rocket stays close to the horizon throughout its visible arc. Low elevation angles mean you need a very clear view of the horizon in the correct direction, with no tall trees, buildings, or terrain blocking the low sky.
Why Can You See a Rocket From So Far Away?
Earth’s surface curves away from an observer at roughly 8 inches per mile squared. At ground level, objects beyond 10 or 15 miles disappear below the horizon. But a rocket climbing to 50 miles of altitude is above the horizon for an observer 500 or more miles away in geometric terms. The rocket is visible because it has risen above the geometric curvature of the Earth, not because the light travels through the ground.
The same principle explains why you can see a satellite pass overhead when it is orbiting 250 miles above the Earth and hundreds of miles away horizontally. Altitude is the key. The faster a rocket climbs, the sooner it becomes visible to distant observers, and the longer it stays above the horizon before moving too far downrange to see.
Reading the LookToSpace Visibility Display
LookToSpace shows you bearing in degrees and as a compass direction label, so you see both 95 degrees and ENE for the same value. Distance to the pad is shown in miles. A visibility quality indicator summarizes whether the combination of distance, trajectory, and launch time makes this a worthwhile viewing opportunity from your location.
The countdown is keyed to liftoff, not to when the rocket becomes visible. If you are 150 miles from the pad, the rocket will not appear above your horizon until 60 to 90 seconds after liftoff. Step outside about two minutes before liftoff, face the indicated bearing, and scan just above the horizon line. That is where you will first see it appear.
Frequently asked questions
What does compass bearing mean in a rocket launch tracker?
Compass bearing is the direction from your location to the launch site, measured in degrees clockwise from north. A bearing of 90 means face due east; 270 means face due west. This tells you exactly which way to turn to see the rocket rise above the horizon.
What is elevation angle for a rocket launch?
Elevation angle is how far above the horizon you look to see the rocket. Zero degrees is the horizon; 90 degrees is straight up. From far away, rockets stay near the horizon, so a low elevation angle means you need a clear view without obstructions in the direction of the pad.
Why do rockets become visible from further away as they climb?
Because altitude overcomes Earth’s curvature. At ground level, objects disappear over the horizon after a few miles. A rocket at 50 miles of altitude is above the geometric horizon for observers hundreds of miles away, just as a mountain peak is visible from across flat terrain.
How do I know if a building or tree will block my view?
Check the elevation angle for your location. If the rocket peaks at 10 degrees elevation, any obstruction taller than about 1 degree of sky in that direction will potentially block it. Moving to an open area like a parking lot, field, or beach eliminates this problem entirely.
Do I need to move during the launch to keep tracking the rocket?
No. Stay facing the compass bearing shown for your location. The rocket rises above that point and climbs higher without moving much laterally at first. It will slowly drift in bearing as it moves downrange, but for the first few minutes the initial bearing is accurate enough to keep it in your field of view.