Lunar Eclipses
Lunar eclipses happen when the Earth totally or partially prevents Sun's light from arriving to the moon. Our planet produces an umbral cone, within which the Sun is invisible, and a penumbral zone where the Sun is only partially visible. During an eclipse, the Moon may just enter the penumbra but not the umbra, or may enter the umbra, totally or partially. This classifies lunar eclipses in three categories (see the diagram):
- Total, when the Moon totally enters the umbral cone.
- Partial, if only part of the Moon entered the umbra.
- Penumbral, if it enters the penumbra but not the umbra.
Both total and partial eclipses have a penumbral phase when the Moon is inside the penumbra but not the umbra, and total eclipses have a partial phase when our satellite is only partially inside the umbra. While total or partial eclipses are noticeable and easy to observe, penumbral ones are not detected by the human eye.
The ephemerides list the circumstances of the eclipses, with the dates and times of the contacts of the lunar limb with the umbra (for total and partial eclipses) and the penumbra. The magnitude of the umbral eclipse (defined as the fraction of the lunar diameter that is obscured by the umbra at the time of maximum eclipse) is also given. A total eclipse has a magnitude greater or equal to 1, while a partial one has a magnitude below 1.
You can find other eclipse predictions here:
- Eclipses Online.
- IAU Working Group on Solar Eclipses Home Page.
- IMCCE (France, in French).
- GSFC Sun-Earth - Eclipse Homepage at NASA/GSFC Sun-Earth Connection Education Forum (Fred Espenak).
- Xavier Jubier's Solar Eclipse Interactive Google Maps.
- Arnold Barmettler's Maps for all Solar Eclipses in the 20th and 21th Century.