Solar eclipse guide
What Is a Solar Eclipse?
A solar eclipse happens when the Moon passes between Earth and the Sun and blocks some or all of the Sun from view.
The basic geometry is simple. The experience on the ground is not. Whether you see a total eclipse, a partial eclipse or no eclipse at all depends on where you are standing.
SunPoint helps with the practical part: turning an astronomical event into a direction you can actually use from where you are.
A solar eclipse occurs when the Moon passes across the Sun as seen from part of Earth.
A small change in observer location can mean the difference between totality, a partial eclipse or no eclipse.
Eclipses near sunrise or sunset can be hidden by buildings, trees, hills or terrain.
During partial phases, direct viewing requires appropriate solar viewing equipment or a safe indirect method.
What actually causes a solar eclipse?
The Moon is much smaller than the Sun, but it is also much closer to Earth. From our viewpoint, the two can appear surprisingly similar in size. When the Moon moves almost exactly between Earth and the Sun, its shadow falls across part of Earth.
This alignment does not happen every month because the Moon's orbit is tilted relative to Earth's orbit around the Sun. Most new moons pass slightly above or below the Sun in our sky.
Total, partial and annular solar eclipses
The Moon completely covers the Sun's bright visible surface for observers inside the narrow path of totality.
The Moon covers only part of the Sun. Some part of the bright solar surface remains visible.
The Moon passes in front of the Sun but appears too small to cover it completely, leaving a bright ring.
Why is an eclipse total in one place but partial somewhere else?
The Moon casts different parts of its shadow onto Earth. The darkest central shadow is the umbra. Around it lies the much larger penumbra. As Earth rotates and the Moon continues along its orbit, these shadows move across Earth's surface.
Observers in the narrow central shadow can experience totality.
Observers in the broader shadow see a partial eclipse instead.
Why your exact location matters
Your location affects when the eclipse begins, when maximum eclipse occurs, how much of the Sun is covered, whether totality is visible, where the Sun appears on your horizon and how high it is in the sky.
This becomes especially important for eclipses close to sunrise or sunset, when buildings, trees, hills or terrain can block a mathematically visible Sun.
Stand here. Look this way.
Choose your location and an eclipse date to see where the Sun will appear relative to your horizon.
- Local maximum time where supported
- Sun azimuth and compass direction
- Sun altitude at maximum
- Direction line on the map
Dynamic location output belongs in the map layer. Article examples below use sourced static circumstances only where stated.
Azimuth and altitude: the two numbers that tell you where to look
Azimuth tells you the compass direction of the Sun. Altitude tells you how high the Sun appears above the horizon. Together, they tell you where to face and how high to look.
Official horizon versus the horizon you can actually see
Astronomical calculations generally assume a defined geometric horizon. Real landscapes do not. A hill, skyline or building can delay when the Sun becomes visible or cause it to disappear early.
How to watch a solar eclipse safely
Never assume that an eclipse makes the Sun safe to look at. During a partial solar eclipse, some of the Sun's bright surface remains visible.
Use suitable solar viewing equipment that meets the relevant safety standard, or use a safe indirect viewing method such as projection. Ordinary sunglasses are not suitable.
Read UKHSA eclipse safety guidance →