A Beginners Guide to Astronomy: Eclipses

A Beginners Guide to Astronomy: Eclipses

Eclipses are true wonders of nature. Although they are fairly frequent, opportunities to admire eclipses are rare. Indeed, there are four to seven solar or lunar eclipses annually, but they are visible only to people who find themselves in the shadow of the eclipse band


What is an eclipse?

An eclipse occurs when light from a celestial body (e.g., the Sun, the Moon, the planets) is temporarily blocked by another celestial body. Eclipses do not happen only on Earth: this phenomenon also occurs on other planets, such as Jupiter or Neptune.


What is a solar eclipse?

A solar eclipse occurs when the Moon passes between the Earth and the Sun and casts his shadow on Earth.

In places that lie in the path of the shadow of the Moon, we get the impression that the Sun is darkened. According to the distance between the Sun and the Moon and their position, it is possible to see three types of solar eclipses:

  • Total Eclipse: the Moon completely covers the Sun.
  • Annular Eclipse: the Moon is closer to the Sun. Thus, the moon appears smaller than the Sun from our point of view. A Sun ring is visible around the moon.
  • Partial Eclipse: the Sun and the moon are not perfectly aligned. Only a part of the Sun is hidden by the moon.



How to observe a solar eclipse in a safe way

During a solar eclipse, it is important to use filter glasses designed for the observation of eclipses (international standard ISO 12312-2). Simple sunglasses are unsuitable: they do not adequately protect your eyes for this type of observation. During a total solar eclipse, the band of shadow at maximum is about 110 to 115 kilometers width, where the Sun is entirely covered by the Moon for a short period (between two and three minutes). It is the time that is the most spectacular since the people lucky enough to be in this band of shade when the eclipse is total can see the solar corona, the chromosphere, solar prominences, and the ways jet ways. It is crucial to take security measures to protect the eyes of before and after the solar phase where the eclipse is total. For those who are outside the band of shadow, the Sun is partially covered by the Moon (partial eclipse). During a partial solar eclipse, eye protection is required at all times. If you do not use filter glasses designed for the observation of eclipses, there are other ways to observe, for example by using a solar eclipse box you can easily make at home.