An annular eclipse of the sun is a rare celestial event that occurs when the moon passes between the sun and the Earth, but does not completely block the sun's disc. Instead, the moon appears slightly smaller than the sun and its outer edge creates a ring of fire, or annulus, around the sun.
This phenomenon occurs because the moon's orbit around the Earth is elliptical, which means that its distance from the Earth varies as it travels around us. When the moon is at its furthest point from the Earth, known as apogee, it appears slightly smaller than the sun, which is why it cannot completely block out the sun's disc during an eclipse.
An annular solar eclipse is not to be confused with a total solar eclipse, in which the Moon does block the entire solar disk. A total solar eclipse reveals the Sun's beautiful, ghostly white corona stretching out from the Moon's black silhouette, during the "totality" phase. But during an annular eclipse, even the thin ring of sunlight is enough to overpower the corona, hiding it from view.
An annular eclipse can only occur during a new moon, when the moon is positioned between the sun and the Earth. The alignment must be precise, with the sun, moon, and Earth perfectly in line, and the moon must be at or near its apogee.
When the annular eclipse begins, the moon appears to take a bite out of the sun's disc, slowly covering more and more of the sun's surface until it reaches its maximum coverage. At this point, the sun appears as a bright ring of fire around the dark silhouette of the moon.
The annular phase of the eclipse typically lasts for a few minutes, after which the moon begins to move away from the sun, gradually uncovering the sun's surface until the eclipse ends.
Note that observers will only see the "ring" if they are in the path of annularity — everyone outside that narrow path will see only a partial eclipse of varying depth.
An annular eclipse is a fascinating event to observe, but it is important to take precautions to protect your eyes. Looking directly at the sun, even during an eclipse, can cause permanent damage to your eyes, so it is crucial to wear special eclipse glasses or use a solar filter to safely view the eclipse.
Annular eclipses are relatively rare, with only a few occurring each year in different parts of the world. The path of the eclipse is determined by the alignment of the sun, moon, and Earth, and can vary widely from one eclipse to the next.
Observing an annular eclipse is a unique and awe-inspiring experience, allowing us to witness the intricate dance of the sun, moon, and Earth as they move through space. Whether you are a seasoned astronomer or a curious observer, an annular eclipse is a sight that is not to be missed.
For information on the April 8, 2024 Total Solar Eclipse, click here.
ANNULAR SOLAR ECLIPSE
October 2, 2024
On October 14, 2023, the next annular eclipse will be visible from North America, Central America, and South America. The map below shows the path of this annular eclipse. To see the eclipse, you'll need to be located somewhere along the path.
CAUTION: Never look at the Sun, either directly or through a telescope, without a professionally made protective solar filter installed that completely covers the front of the instrument, or permanent eye damage could result. Note that in an annular eclipse, there is no period of "totality" as in a total solar eclipse.