Types of solar and lunar eclipses

Eclipses have been the subject of superstition and scientific curiosity throughout history. timeanddate.com explores the different types of eclipses.

Types of solar eclipses

A solar eclipse falls in the following categories:

• Total solar eclipse.
• Partial eclipse.
• Annular eclipse.

A total solar eclipse occurs when the moon completely covers the sun, as seen from earth. They happen because the sun is near one of the nodes of the lunar orbit, and the moon is at perigee (the point in the orbit of the moon or a satellite at which it is nearest to the earth) at this node at the same time. The solar eclipse has been linked to many ancient customs and traditions.

A partial solar eclipse occurs when only the lunar penumbra (the partially shaded outer region of the shadow cast by an object) touches the earth and the umbra casts off into space and misses the earth. The percentage of the sun varies depending on the observer’s location but regardless of a viewer’s position, the sun will only be partially eclipsed.

Annular eclipses occur when the moon appears smaller than the sun as it passes centrally across the solar disk and a bright ring, or annulus, of sunlight remains visible during the eclipse.

There is also a “hybrid” eclipse, which is a type of central eclipse where parts of the path are annular while other parts are total. At the extremes of the eclipse’s solar central path, the moon appears too small to mask the sun entirely and yields an annual eclipse. However, due to earth’s curvature, the moon’s size appears to increase to block the entire solar disk and produces a very short total eclipse. These eclipses are rare.

Check out some basic tips on viewing eclipses.

Types of lunar eclipses

The lunar eclipse occurs when the moon passes through the earth’s shadow and can only happen at a full moon. One of the major differences between a lunar and solar eclipse is that a lunar eclipse can be viewed from across the entire night side of the earth (depending on weather). Types of lunar eclipses include:

• The total lunar eclipse, which occurs when the moon’s travels completely into the earth’s umbra. The moon never complete disappears during a total lunar eclipse.
• The partial lunar eclipse, which occurs when the moon is oriented in a way that only part of it dips into the earth’s umbra.
• The penumbral lunar eclipse, which occurs when the moon passes through the faint penumbral portion of the earth’s shadow.

There is always a full moon on the night of a lunar eclipse. The eclipse’s type and length depends on the moon’s location relating to its orbital nodes (one or two points where an orbit crosses a plane of reference that it is inclined to). A lunar eclipse has two magnitude values – the penumbral magnitude and the umbral magnitude.

A popular activity during a partial lunar eclipse viewing is to videotape the eclipse through a telescope. However, others may prefer a lightweight camcorder for later analysis.

Interesting Fact

Totality of a solar eclipse can last about seven minutes and 31 seconds but these eclipses are rare. It is predicted that totality during the solar eclipse will last for seven minutes and 14 seconds in the year 2150, which is longer than any total solar eclipse since the ninth century. A period of totality is normally shorter than five minutes.

While a solar eclipse is seen over only a small part of the day side of earth and changes in appearance, a lunar eclipse can be viewed from across the entire night side of the earth (depending on weather) and will appear exactly the same for all observers on the earth’s night hemisphere.