Lunar Eclipse

In a lunar eclipse, the sun, the earth, and the moon all play a role. Lunar eclipse happens when the Earth passes between the sun and the moon. When this happens, the earth’s shadow covers the moon, causing it to be temporarily darkened.

How Does Lunar Eclipse Occur:

A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the Sun, Earth, and Moon are aligned exactly in a straight line, or very closely, with the Earth in the middle. Hence, a lunar eclipse can only occur at the night of a full moon. The type and length of an eclipse depend upon the Moon’s location relative to its orbital nodes.

A lunar eclipse occurs only when the full moon is at one of the nodes of the lunar orbit, a place where two tracks intersect. The lunar orbit is the orbit of the moon around the earth. The lunar orbit is elliptical (like a stretched circle). At the start of the eclipse, a shadow, or the penumbra, will slowly start to cover the moon. As the moon moves further into the Earth’s shadow, it will eventually cover the entire moon.

Lunar Eclips

Lunar Eclips Dates:

15-06-2011, total lunar eclipse

19-10-2013, the lunar eclipse in the penumbra

04-03-2007, partial lunar eclipse

Types of Lunar Eclipses:

An eclipse of the Moon (or lunar eclipse) can only occur at Full Moon, and only if the Moon passes through some portion of Earth’s shadow. That shadow is composed of two cone-shaped components, one nested inside the other. The outer or penumbral shadow is the zone where the Earth blocks partly which means  the Sun’s rays are partly reflecting on the Moon. In contrast, the inner or umbral shadow is a region where the Earth blocks all direct sunlight from sun to the Moon.

Astronomers recognize three basic types of lunar eclipses:

1. Penumbral Lunar Eclipse
◾ The Moon passes through Earth’s penumbral shadow.
◾ These events are of only academic interest because they are subtle and hard to observe.

2. Partial Lunar Eclipse
◾ A portion of the Moon passes through Earth’s umbral shadow.
◾These events are easy to see, even with naked eye.

3. Total Lunar Eclipse (Blood Moons)
◾ The entire Moon passes through Earth’s umbral shadow.
◾These events are quite striking due to the Moon’s vibrant red color during the total phase (totality).

Now you might be wondering: If the Moon orbits Earth every 29.5 days and lunar eclipses only occur at Full Moon, then why don’t we have an eclipse once a month during Full Moon?”. You see, the Moon’s orbit around Earth is actually tipped about 5 degrees to Earth’s orbit around the Sun. This means that the Moon spends most of the time either above or below the plane of Earth’s orbit. And the plane of Earth’s orbit around the Sun is important because Earth’s shadows lie exactly in the same plane. During Full Moon, our natural satellite usually passes above or below Earth’s shadows and entirely misses them and thus no eclipse takes place. But two to four times each year, the Moon passes through some portion of the Earth’s penumbral or umbral shadows and one of the above three types of eclipses occurs.

When an eclipse of the Moon takes place, everyone on the night side of Earth can see it. About 35% of all eclipses are of the penumbral that are difficult to see even with a telescope. Another 30% are partial eclips that  are easy to see with an eye. The final 35% or so are total eclipses, and these are quite extraordinary events to observe.

How many lunar eclipses occur per year?

Approximately two to three total lunar eclipses occur in any given year. Unlike a solar eclipse, which can only be viewed from a certain relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of the Earth. A lunar eclipse lasts for a few hours, whereas a total solar eclipse lasts for only a few minutes at any given place, due to the smaller size of the moon’s shadow. Also unlike solar eclipses, lunar eclipses are safe to view without any eye protection or special precautions, as they are dimmer than the full moon.

Observable lunar eclipses in the Benelux region for the next two years (2015-2017) are:
Date Time Type embezzlement
September 28, 2015 04:47 pm total
September 16, 2016 20:54 pm penumbra
February 11, 2017 01:44 pm penumbra
August 7, 2017 20:21 pm partially