What is an annular solar eclipse? When does this phenomenon occur? Read to find all the answers...
Life is a game of light and shadows and it continues on a grand cosmic scale in the form of solar and lunar eclipses.
As the large shadow of the Moon, positioned exactly between the Earth and Sun, passes rapidly over the spinning Earth, a solar eclipse can be observed in the path of the shadow, as it travels across the Earth's surface. Of the many types of eclipses that may be observed, Let us see a rare kind, the annular solar eclipse.
What Are Solar Eclipses?
Let us investigate what is this 'shady' business of eclipses, before moving on further to understand the special case of an annular solar eclipse. The Earth revolves around the Sun and Moon revolves around the Earth. A shadow is caused by the obstruction of light by any object as you hold it in front of a light source.
Both the Earth and Moon cast gigantic shadows across the space and once in a while they get aligned in a line with the Sun on one end, causing the events which are called 'eclipses'.
A lunar eclipse is caused when the Moon, Earth and Sun are aligned in a line and the Earth casts a shadow over the Moon 'eclipsing' it.
When the Moon gets aligned in a straight line between the Earth and the Sun (on a New Moon), the moon casts a shadow on the Earth. Any person standing in the path of the dense shadow (called Umbra) cast by the Moon, will see the Sun being covered by the lunar disk, giving rise to a total solar eclipse.
Those who stand outside the dense part of the shadow (in the penumbra of Moon's shadow), will observe a partial solar eclipse. The cone tip of the dense shadow (umbra) touching the Earth's surface is causing a total solar eclipse. An annular eclipse is where the Moon is further away from Earth and the 'Umbra' cone doesn't reach the Earth.
Thus, this special type of eclipse occurs when the tip of the moon's shadow cone (umbra) doesn't reach the Earth, due to which the moon's diameter cannot cover the Sun.
When Does an Annular Solar Eclipse Occur?
In the case of an annular eclipse, the whole solar disk is not completely covered by the Moon as its umbra cone tip never reaches the Earth. The tip of the umbra passes over the Earth's surface, the regions which are exactly opposite to it observe the moon covering the central part of the Sun.
It leaves a concentric bright 'Annular' ring visible around the central circular dark region during the eclipse. This is the reason why such eclipse is known by the name of an 'Annular' eclipse.
When Is the Next One?
On 26th December, 2019 the next annular eclipse will be seen but only through select regions of the world. Some of those are Eastern Europe, Asia, North-West Australia, East Africa, the Pacific, and the Indian Ocean.
Date and Regions of Visibility of Annual Solar Eclipses
Upcoming Annual Solar Eclipses are:
26 Dec, 2019~ East in Europe, Much of Asia, North/West Australia, East in Africa, Pacific, Indian Ocean
21 Jun, 2020~South/East Europe, Much of Asia, North in Australia, Much of Africa, Pacific, Indian Ocean
10 Jun, 2021~Much of Europe, Much of Asia, North/West Africa, Much of North America, Atlantic, Arctic
14 Oct, 2023~West in Africa, North America, South America, Pacific, Atlantic, Arctic
2 Oct, 2024~Much of South America, Pacific, Atlantic, Antarctica