How T0 See A Penumbral Lunar Eclipse? and Total Eclipse of Moon Looks Like
Unlike solar eclipses, which can only be seen along a narrow path on Earth, eclipses of the Moon can be observed all across the night-side of Earth when the eclipse happens.
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 apenumbral magnitude that is more than 0.60.
Lunar eclipses are some of the most easy-to-watch astronomical events. All you need is to see them, are clear skies and a pair of eyes.
Lunar eclipses occur on a full Moon night when the Sun, Earth and Moon are aligned in a straight line or almost straight line in space. Anyone on the night-side of the Earth at the time of the eclipse can see it.
Viewing a lunar eclipse, whether it is a partial,penumbral or total eclipse of the Moon, requires little effort. All you need is a clear view of the Moon and the Sky, clothes to keep your warm at night, and a chair so that you can be comfortable while watching the eclipse.
The Moon does not have its own light, but shines because its surface reflects the Sun’s rays.
Eclipses of the Moon happen when the Sun, Earth and Moon are aligned to form an exact or an almost straight line. The technical term for this is syzygy, which comes from the Greek word for being paired together.
Why do Total Lunar Eclipses happen?
During a Total Lunar Eclipse, the Sun, Earth and Moon form a straight line. The Earth blocks any direct sunlight from reaching the Moon. The Sun is behind the Earth, so the Sun’s light casts the Earth’s shadow on the Moon. This shadow covers the entire Moon and causes a Total Lunar Eclipse.
Upcoming 5 Total Lunar Eclipses
|Dates||Path of the eclipse|
|31 Jan 2018|
|27 Jul / 28 Jul 2018|
|20 Jan / 21 Jan 2019|
|26 May 2021|
|15 May / 16 May 2022|
More details about upcoming Eclipses
Earth’s Three Shadows
The Earth’s shadow can be divided into three parts:
- Penumbra – the outer part.
- Umbra – darker, central part.
- Antumbra – a partly shaded area beyond the umbra.
Sun, Earth and Moon Aligned
For a lunar eclipse to occur, the Sun, Earth and Moon must be roughly aligned in a straight line. If the Sun, Earth and Moon do not align, the Earth cannot cast a shadow on the Moon’s surface and an eclipse cannot happen.
When the Sun, Earth and Moon are not perfectly aligned, only the outer part of the Earth’s shadow covers the Moon. Such an eclipse is called a penumbral lunar eclipse. In a Total Lunar Eclipse, the Earth’s umbra completely covers the Moon.
The Earth’s umbra is about 870,000 miles (1.4 million km) wide.
Only at Full Moon
Total Lunar Eclipses happen only when:
- The Sun, Earth and Moon are in a straight line.
- There is a full Moon.
Full Moon and Total Lunar Eclipses
Why don’t we see a lunar eclipse every month if a full Moon is needed for a Total Lunar Eclipse?
This is because the plane of the Moon’s orbital path around the Earth is inclined at an angle of 5° to the Earth’s orbital plane, also known as the ecliptic, around the Sun. The points where the 2 orbital planes meet are calledlunar nodes. Eclipses can only take place near the lunar nodes and lunar eclipses occur when a full Moon happens near a lunar node.
The Moon Looks Red
Even though the Earth completely blocks sunlight from directly reaching the surface of the Moon, the Moon is still visible to the naked eye during a Total Lunar Eclipse. This is because the Earth’s atmosphere refracts sunlight and indirectly lights up the Moon’s surface.
The Earth’s atmosphere removes or blocks parts of the sunlight’s spectrum leaving only the longer wavelengths. Because of this, a totally eclipsed Moon usually looks red.
Eclipses in Different Colors
A lunar eclipse can also be yellow, orange, or brown in color. This is because different types of dust particles and clouds in the Earth’s atmosphere allow different wavelengths to reach the surface of the Moon.
Seven Stages of the Eclipse
A Total Lunar Eclipse usually happens within a few hours. Totality can range anywhere from a few seconds to about 100 minutes. The July 26, 1953 Total Lunar Eclipse had one of the longest periods of totality in the 20th century – 100 minutes and 43 seconds.
There are seven stages of a Total Lunar Eclipse:
- Penumbral eclipse begins: This begins when the penumbral part of Earth’s shadow starts moving over the Moon. This phase is not easily seen by the naked eye.
- Partial eclipse begins: The Earth’s umbra starts covering the Moon, making the eclipse more visible.
- Total eclipse begins: Earth’s umbra completely covers the Moon and the Moon is red, brown or yellow in color.
- Maximum eclipse: This is the middle of the total eclipse.
- Total eclipse ends: At this stage, the Earth’s umbra starts moving away from the Moon’s surface.
- Partial eclipse ends: The Earth’s umbra completely leaves the Moon’s surface.
- Penumbral eclipse ends: At this point the eclipse ends and the Earth’s shadow completely moves away from the Moon.