A solar eclipse occurs when a portion of the Earth is engulfed in a shadow cast by the Moon which fully or partially blocks sunlight. This occurs when the
Sun, Moon and Earth are aligned. Such alignment coincides with a new moon indicating the Moon is closest to the ecliptic plane In a total eclipse , the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses, only part of the Sun is obscured.
AN ECLIPSE, IN GENERAL, IS DEFINED AS:
the total or partial obscuring of one celestial body by another
the passing into the shadow of a celestial body
Two types of eclipses
There are two types of eclipses, following each situation defined above.
LUNAR ECLIPSE
A lunar eclipse is caused by the moon passing through the Earth’s shadow. This phenomenon is relatively common since all it requires is two celestial bodies to be lined up. Once it does happen, half of Earth -- the half that can see the moon at night -- can observe the phenomenon.
SOLAR ECLIPSE
A solar eclipse occurs when the moon “eclipses” the sun. This means that the moon, as it orbits the Earth, comes in between the sun and the Earth, thereby blocking the sun and preventing any sunlight from reaching us.
There are four types of solar eclipses
Partial solar eclipse : The moon blocks the sun, but only partially. As a result, some part of the sun is visible, whereas the blocked part appears dark. A partial solar eclipse is the most common type of solar eclipse.
Annular solar eclipse: The moon blocks out the sun in such a way that the periphery of the sun remains visible. The unobscured and glowing ring, or “annulus,” around the sun is also popularly known as the “ring of fire.” This is the second most common type of eclipse.
Total solar eclipse : As the word "total" suggests, the moon totally blocks out the sun for a few minutes, leading to a period of darkness -- and the resulting eclipse is called a total solar eclipse. During this period of darkness, one can witness the solar corona, which is usually too dim to notice when the sun is at its full glory. Also noticeable is the diamond ring effect, or "Baily's beads," which occurs when some of the sunlight is able to reach us because the moon's surface is not perfectly round. These imperfections (in the form of craters and valleys) can allow sunlight to pass through, and this appears just like a bright, shining diamond.
Hybrid solar eclipse: The rarest of all eclipses is a hybrid eclipse, which shifts between a total and annular eclipse. During a hybrid eclipse, some locations on Earth will witness the moon completely blocking the sun (a total eclipse), whereas other regions will observe an annular eclipse.
How can your eyes be affected by a solar eclipse?
Exposing your eyes to the sun without proper eye protection during a solar eclipse can cause “eclipse blindness” or retinal burns, also known as solar retinopathy. This exposure to the light can cause damage or even destroy cells in the retina (the back of the eye) that transmit what you see to the brain. This damage can be temporary or permanent and occurs with no pain. It can take a few hours to a few days after viewing the solar eclipse to realize the damage that has occurred
A few common ways to safely watch a solar eclipse:
Pinhole projection : This is the safest and most inexpensive way to watch a solar eclipse. This helps you avoid looking directly at the eclipse by using a projected image. This do-it-yourself project includes making a pinhole in a cardboard paper with the sun on one side and a piece of paper three feet away without obstruction to project the image on the other side. Keep in mind not to look through the pinhole at the sun.
Welder’s glass: Number 14 welder’s glass provides effective protection and can be found at a local welder’s supply store. This glass will reduce the harmful rays that are emitted during the eclipse. Do not use if there are any scratches or damage to the glass.
Mylar filters: Aluminized mylar plastic sheets are available as eclipse vision glasses or can be cut and made into a viewing box.
How not to watch a solar eclipse
Be careful about how you watch a solar eclipse. It is not recommended to view it in the following ways:
Smartphone : Watching a solar eclipse on your smartphone camera can put you at risk of accidentally looking at the sun when trying to line up your camera. It could possibly also damage your smartphone camera. Don’t take the risk.
Camera viewfinder: Never look at a solar eclipse through the optical viewfinder of a camera. It can damage your eyes in the same way as looking directly at it Unsafe filter
When is the next solar eclipse?
The next solar eclipse is an annular, or "ring of fire" eclipse that will take place on June 21, 2020. It will be visible from much of Africa, southeast Europe and most of Asia, with a partial eclipse visible in northern Australia.