You’ve probably noticed that the Moon appears larger when it lies just above the horizon. This is just an optical illusion. However, the Moon actually does vary in its distance from Earth because its orbit is eliptical. This, in turn, affects its apparent size also. When the Moon is nearest to Earth, it appears roughly 14 percent larger than when the Moon is farthest from Earth.
This variation in size is usually not readily apparent, but it becomes obvious during an annular solar eclipse. An annular eclipse occurs when the Moon is near apogee, its farthest point from Earth. The Moon passes directly in front of the Sun but is too far from Earth to cover the entire Sun. Instead of producing a total eclipse, this results in an eclipse in which the rim of the Sun is visible the whole way around the Moon.
An annular solar eclipse will occur in the Americas on October 14. The 125-mile-wide path of annularity will begin in the Pacific before crossing parts of Oregon, California, Nevada, Utah, Arizona, Colorado, New Mexico, and Texas. The path of annularity will then cross the Gulf of Mexico before passing over parts of Mexico, the Central American countries (except for El Salvador), Colombia, and Brazil. A partial solar eclipse will be visible from all of North and South America except for western Alaska and the southern parts of Chile and Argentina.
The Orionid meteor shower will peak on the night of October 21–22. The Orionid shower is an average performer, with peak meteor rates of about 20 per hour. This year, the Moon will set in the middle of the night on the peak night of the shower, leaving the early morning hours dark for meteor viewing.
A partial lunar eclipse will occur on the night of October 28–29. This eclipse will be visible from Europe, Asia, Africa, and most of Australia. All of the Moon will be dimmed slightly by Earth’s penumbra (partial shadow), but only the southeastern edge of the Moon will be eclipsed by the full shadow, or umbra. Maximum eclipse will occur at 20:14 UTC on October 28.
In Our Skies, September 2023: Annular Solar Eclipse
