What is a lunar eclipse?

Astronomically, lunar eclipses are a fairly common phenomenon, with about three occurring each year. According to the Time&Date website, approximately 29% of lunar eclipses are total. So, on average, a total lunar eclipse can be observed once every 2.5 years.

Lunar eclipses usually last a few hours, and the duration of total darkness of the moon ranges from thirty minutes to over an hour. This event is easier to observe than a solar eclipse because any observer with the moon above his horizon can see them with the naked eye. In addition, the total solar eclipse lasts a maximum of seven and a half minutes; This difference is due to the much smaller diameter of the moon compared to the sun.

Although the Earth’s moon is full once a month, we do not see an eclipse every month. The reason is that the moon’s orbit around the earth is not in a flat plane and its angle is about five degrees. So when the moon goes around the earth, it passes over or under its shadow.

A lunar eclipse is one of the easiest sky events to observe. To watch it, simply go outside, look at the sky and enjoy! Almost everyone on the night side of the Earth will be able to see the total lunar eclipse. For this reason, most people have a better chance of seeing a lunar eclipse than a total solar eclipse.

You do not need a telescope or other special equipment to watch the eclipse. However, binoculars or small telescopes can be interesting to see the surface details.

Scientists also like to watch lunar eclipses. Throughout history, they have gained a very good knowledge of what happens during a total lunar eclipse. Much of our current knowledge comes from studying the moon and sun during eclipses.

In ancient times, eclipses, in addition to fiction and creating panic among people, raised many questions about the geometry of the solar system. What makes the moon and the sun disappear? What is the pattern in this? This caused the ancient Greeks to infer that the earth is spherical by studying the shadow of the earth on the moon. “Aristarchus of Samos” also estimated the diameter of the moon in the 3rd century BC by predicting the lunar eclipse.

The color of the moon can give us information about Earth’s weather conditions and pollution. Analysis of the refracted light of the Earth’s atmosphere during the lunar eclipse that causes the blood moon showed that atmospheric ozone is confined to a layer between 50 and 80 kilometers above the Earth’s surface.

Nowadays, studying the moon during an eclipse is not very useful. We seem to have learned all we need to from them, and other studies have become easier with satellites. Now the only importance of this event is cultural and visual.

There are two lunar eclipses in most calendar years. Some years there are one or three eclipses and some years none. An observer who remains in the same place can see 19 or 20 lunar eclipses in 18 years if the sky is not cloudy.

During that period, three or four total eclipses and six or seven partial eclipses may be visible from start to finish. It is possible that five total eclipses and four or five partial eclipses will be visible to some extent. All these numbers can be obtained from the geometry of eclipses.

The geometry of eclipses includes three components: the Earth, the Sun, and the Moon. The geometric stages include two types of total and partial lunar eclipses. Astronomers predict the time of eclipses by considering the geometrical principles and the angles between the three bodies.

Examining the repeated patterns of eclipses in the past and using astronomical software can also be useful to know the time of the next eclipse.

In the table below, you can check the information of the next five lunar eclipses with other details.