What is a Penumbral Lunar Eclipse?
Next Eclipse: Annular Solar Eclipse – Thu, Sep 1, 2016 … See animation
Next Penumbral Lunar Eclipse: Fri, Sep 16, 2016 … See animation
A penumbral lunar eclipse takes place when the Moon moves through the faint, outer part of the Earth's shadow. This type of eclipse is often mistaken for a normal full Moon.
The Moon shines because its surface reflects the Sun's rays. A lunar eclipse happens when the Earth comes between the Sun and the Moon and blocks sunlight from directly reaching the Moon.
A penumbral lunar eclipse occurs when the Sun, Earth, and Moon align in an almost straight line. When this happens, the Earth blocks some of the Sun's light from directly reaching the Moon's surface, and covers a part of the Moon with the outer part of its shadow, also known as the penumbra. The rest receives the same amount of sunlight as usual and is as bright as a full Moon.
Upcoming 5 Penumbral Lunar Eclipses
|Dates||Path of the eclipse|
|Sep 16 / Sep 17, 2016|
|Feb 10 / Feb 11, 2017|
|Jan 10 / Jan 11, 2020|
|Jun 5 / Jun 6, 2020|
|Jul 4 / Jul 5, 2020|
Because of this, it is often hard to differentiate between a normal full Moon and a penumbral eclipse of the Moon.
Two celestial events must happen at the same time for a penumbral lunar eclipse to occur:
- the Moon should be a full Moon, and
- the Sun, Earth and Moon must be imperfectly aligned in a straight line.
The reason we do not see a lunar eclipse every full Moon night is because of the inclination of the Moon's orbital path. The plane of the Moon's orbit around the Earth is inclined at an angle of 5° to the Earth's orbital plane (ecliptic) around the Sun. The points where the two orbital planes meet are called lunar nodes. Lunar eclipses can only take place when a full Moon occurs near one of the lunar nodes.
How to See a Penumbral Lunar Eclipse?
About one-third of all lunar eclipses are penumbral. They are, however, easy to miss because when they happen, the eclipsed Moon tends to look very similar to a full Moon. In fact, it is impossible to observe the start and end of a penumbral lunar eclipse, even with telescopes.
Only penumbral eclipses where a large portion of the Moon is in the Earth's penumbral shadow may be detectable to observers on Earth. Trained eyes can usually see penumbral eclipses with a penumbral magnitude that is more than 0.60.
Next eclipse begins in
Sep 1, 2016 at 6:13 AM UTC … See more
- Different Types of Eclipses
- What are Solar Eclipses?
- Total Solar Eclipses
- Partial Solar Eclipses
- Annular Solar Eclipses
- Solar Eclipses in History
- Solar Eclipse Myths and Superstitions
- Magnitude of Eclipses