Whereas lunar eclipses are safe to view with the naked eye, solar eclipses are not. You must take the necessary precautions to keep from harming your eyesight. In fact, you also need to use a “solar filter” to keep from harming your camera’s imaging sensor as well as for correct exposure.
A solar eclipse occurs whenever the moon’s shadow falls on Earth. This can only occur during a new moon, when the moon passes between the sun and Earth. There are two or more solar eclipses a year; which occur when the geometry lines up just right, so that part of the moon’s shadow falls on Earth’s surface and an eclipse of the sun is seen from that region.
Partial and Total Solar Eclipses
The moon’s cone-shaped shadow has two parts, the penumbra and the umbra. The penumbra is the moon’s faint outer shadow and partial eclipses are visible from within the penumbral shadow. The umbra is the moon’s dark inner shadow and total solar eclipses are visible from within the umbral shadow. The track of the moon’s umbral shadow across Earth is called the Path of Totality, and it covers less than 1 percent of Earth’s surface area (typically 10,000 miles long and about 100 miles wide.)
A solar eclipse begins as a small notch slowly appears along one edge of the sun. During the next hour, the moon will gradually cover more and more of the sun’s bright disk. If the eclipse is a total solar eclipse, the last remaining minutes of the partial phases can be dramatic. The crescent of the sun grows thinner as the moon’s shadow approaches. The abrupt darkness of totality is stunning to view, and the solar corona is an awe-inspiring sight. The sun’s corona can only be seen during the few brief minutes of totality.
Annular Solar Eclipses
A total solar eclipse occurs when the moon is on the near side of its elliptical orbit. When the moon is on the far side of its orbit, it appears smaller and can’t completely cover the sun. It is during these eclipses that the moon’s antumbra shadow (the extension of the umbra) reaches Earth, causing an annular eclipse for people who are within the track of the antumbra (also called the path of annularity). During this type of eclipse, you will see a ring or annulus of bright sunlight surrounding the moon at the maximum phase.
Just as with the partial eclipse of the sun, you must take precautions and use a solar filter to view the annular eclipse. Annularity can last up to 12 minutes.
A third type of solar eclipse, that may rarely occur, is called a hybrid eclipse. A hybrid eclipse is the name given to a total eclipse that changes to an annular eclipse or an annular eclipse that changes to a total eclipse. They are sometimes called annular/total eclipses. Hybrid eclipses occur when the curvature of Earth brings different points of the path into the total and annular shadows respectively.