Solar Eclipse

What is a Solar Eclipse?

What is a solar eclipse? Not to be confused with a lunar eclipse, a solar eclipse occurs when the Moon lines up precisely in front of the Earth so that the Moon blocks the Sun’s rays and the Moon’s shadow falls upon the Earth. This relatively rare occurrence only happens during a new moon, when the Earth, Moon and Sun are exactly or very closely aligned, with the Moon in the middle. The shadow cast can partially or totally cover the Moon, which can result in a total eclipse, partial eclipse or annular eclipse for Earth’s viewing pleasure. The type and length of a solar eclipse depends upon the Moon’s location relative to its orbital nodes. A total solar eclipse lasts for only a few minutes and can only be viewed by those along a narrow path of the Earth’s surface. As it is dangerous to look directly at the Sun, observers should use special eye protection or indirect viewing techniques.

Solar Eclipse Frequency

If the Moon were in a circular orbit close enough to the Earth and in the same orbital plane, there would be total solar eclipses every single month. However, the Moon’s orbit is angled at more than 5 degrees to the earth’s orbit around the sun so its shadow at new moon often misses the Earth. The Earth’s orbit is called the ecliptic plane as the Moon’s orbit must cross this plane in order for an eclipse (both solar as well as lunar) to occur. In addition, the Moon’s actual orbit is elliptical, often taking it far enough away from the Earth so that its apparent size is not large enough to block the Sun totally. The orbital planes cross each year at a line of nodes resulting in at least two, and up to five, solar eclipses occurring each year; no more than two of which can be total eclipses. Total solar eclipses are nevertheless rare at any particular location because totality exists only along a narrow path on the Earth’s surface traced by the Moon’s shadow or umbra.

Solar eclipses can occur 2 to 5 times per year, at least once per eclipse season. Since the Gregorian calendar was instituted in 1582, years that have had five solar eclipses were 1693, 1758, 1805, 1823, 1870, and 1935. The next occurrence will be 2206.

Solar Eclipse vs. Lunar Eclipse

Unlike a lunar eclipse, which may be viewed from anywhere on the night side of the Earth, a solar eclipse can only be viewed from a certain relatively small area of the world. A a total solar eclipse lasts for only a few minutes at any given place due to the smaller size of the moon’s shadow, whereas a lunar eclipse lasts for a few hours. Also unlike lunar eclipses, solar eclipses are not safe to view without any eye protection or special precautions, as it is dangerous to look directly at the Sun.

Solar Eclipse Types

Solar Eclipse

Solar Eclipse

There are four types of solar eclipses. An eclipse that occurs when the Moon is near its closest distance to the Earth (i.e., near its perigee) can be a total eclipse because the Moon will appear to be large enough to cover completely the Sun’s bright disk, or photosphere. Conversely, an eclipse that occurs when the Moon is near its farthest distance from the Earth (i.e., near its apogee) can only be an annular eclipse because the Moon will appear to be slightly smaller than the Sun. Slightly more solar eclipses are annular than total because, on average, the Moon lies too far from Earth to cover the Sun completely. A hybrid eclipse occurs when the magnitude of an eclipse changes during the event from smaller than one to larger than one—or vice versa—so the eclipse appears to be total at some locations on Earth and annular at other locations.

  • Total Eclipse. A total eclipse occurs when the dark silhouette of the Moon completely obscures the intensely bright light of the Sun, allowing the much fainter solar corona to be visible. During any one eclipse, totality occurs at best only in a narrow track on the surface of the Earth.
  • Annular Eclipse. An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the outline of the Moon. The next annular eclipse is on May 10, 2013.
  • Hybrid Eclipse. A hybrid eclipse (also called annular/total eclipse) shifts between a total and annular eclipse. At certain points on the surface of the Earth it appears as a total eclipse, whereas at other points it appears as annular. Hybrid eclipses are comparatively rare.
  • Partial Eclipse. A partial eclipse occurs when the Sun and Moon are not exactly in line and the Moon only partially obscures the Sun. This phenomenon can usually be seen from a large part of the Earth outside of the track of an annular or total eclipse. However, some eclipses can only be seen as a partial eclipse, because the umbra passes above the Earth’s polar regions and never intersects the Earth’s surface.

Because the Earth’s orbit around the Sun is also elliptical, the Earth’s distance from the Sun similarly varies throughout the year. This affects the apparent size of the Sun in the same way, but not so much as with the Moon’s varying distance from the Earth. When the Earth approaches its farthest distance from the Sun in July, a total eclipse is somewhat more likely, whereas conditions favor an annular eclipse when the Earth approaches its closest distance to the Sun in January.

When is the next Solar Eclipse?

The solar eclipse calendar is a listing of all solar eclipses from 2010 through 2015. Times are expressed in Coordinated Universal Time (UT), the international basis for other time zones. The type and length of a solar eclipse depends upon the Moon’s location relative to its orbital nodes. A solar eclipse lasts for only a few minutes and can only be viewed from those located on a narrow path of the Earth’s surface. For additional solar eclipse dates, please see NASA’s solar eclipse page.

Solar Eclipse Year Date Duration Geographic Visability
Annular 2010 Jan 15 11m08s Africa, Asia
Total 2010 Jul 11 05m20s s S. America
Partial 2011 Jan 04 Europe, Africa, c Asia
Partial 2011 Jun 01 e Asia, n N. America, Iceland
Partial 2011 Jul 01 s Indian Ocean
Partial 2011 Nov 25 s Africa, Antarctica, Tasmania, N.Z.
Annular 2012 May 20 05m46s Asia, Pacific, N. America
Total 2012 Nov 13 04m02s Australia, N.Z., s Pacific, s. S. America
Annular 2013 May 10 06m03s Australia, N.Z., c Pacific
Hybrid 2013 Nov 03 01m40s e Americas, s Europe, Africa
Annular 2014 Apr 29 s Indian, Australia, Antarctica
Partial 2011 Oct 23 n Pacific, N. America
Total 2015 Mar 20 02m47s Iceland, Europe, n Africa, n Asia
Partial 2015 Sep 13 s Africa, s Indian, Antarctica

Solar Eclipse Cycle

If the date and time of any solar eclipse are known, it is possible to predict other eclipses using eclipse cycles. The saros is probably the best known and one of the most accurate eclipse cycles. A saros lasts 6,585.3 days (a little over 18 years), which means that after this period a practically identical eclipse will occur. The most notable difference will be a shift of 120° in longitude (due to the 0.3 days) and a little in latitude. A saros series always starts with a partial eclipse near one of Earth’s polar regions, then shifts over the globe through a series of annular or total eclipses, and ends at the opposite polar region. A saros series lasts 1226 to 1550 years and 69 to 87 eclipses, with about 40 to 60 central.

Solar Eclipse Mythology

A solar eclipse is a natural phenomenon. Nevertheless, in some ancient and modern cultures, solar eclipses have been attributed to supernatural causes or regarded as bad omens. A total solar eclipse can be frightening to people who are unaware of their astronomical explanation, as the Sun seems to disappear during the day and the sky darkens in a matter of minutes.

Moon Phases, Full Moons and Moon Calendars

As the Moon orbits Earth, it changes phase in an orderly way. Follow these links to understand the various phases of the moon.

Full Moons

Full Moon | Full Moon Names | Blue Moon | Wolf Moon | Snow Moon | Worm Moon | Pink Moon | Flower Moon | Strawberry Moon | Buck Moon | Sturgeon Moon | Harvest Moon | Hunters Moon | Beaver Moon | Cold Moon |

Moon Phases

Understanding Moon Phases | New Moon | Waxing Crescent Moon | First Quarter Moon | Waxing Gibbous Moon | Full Moon | Waning Gibbous Moon | Last Quarter Moon | Waning Crescent Moon |

Moon Calendars

Full Moon Calendar | Lunar Calendar | Lunar Eclipse Calendar | Solar Eclipse Calendar | Full Moon Calendar 2011 | Full Moon Calendar 2012 | Full Moon Calendar 2013 | Full Moon Calendar 2014 | Full Moon Calendar 2015 | Full Moon Calendar 2016 | Full Moon Calendar 2017 | Full Moon Calendar 2018 | Full Moon Calendar 2019 | Full Moon Calendar 2020 |

Eclipses & Moon Facts

Lunar Eclipse | Solar Eclipse | Solar Eclipse vs. Lunar Eclipse | Facts About The Moon |