December 26 – Waiting for the partial solar eclipse after three years of absence

On December 26, Vietnamese have the opportunity to observe the incredible partial solar eclipse with a coverage rate of 30-67% (depending on location). The entire partial eclipse will take over 3 hours. In Vietnam, it is a rare solar eclipse after 3 years of absence, since the last time in March 2016.

What is a solar eclipse?

The Earth revolves around the Sun and the Moon revolves around the Earth. Sometimes these three objects will line up. If the Moon is located between the Sun and the Earth, preventing sunlight from reaching our planet, then the phenomenon will take place. eclipse.

Although the Sun is about 400 times larger than the Moon, the distance from our Earth to the Sun is 400 times the distance to the Moon, so when viewed from Earth, the two objects appear to be the same size. A beautiful creative arrangement!

Causes of eclipses: Where the Moon is completely in shadow, a total eclipse will occur, while where it is only in penumbra, a total eclipse will occur outside of Partial Eclipse. Source: Tyler Morning Telegraph

Depending on the relative position between the three celestial bodies of the Sun, Earth and Moon, 3 types of eclipses are observed:

• total solar eclipse: occurs when the Earth, the Moon and the Sun are exactly on the same line, and the Moon will perfectly fit the Sun. This type of eclipse can only be observed at places located in the middle of the shadow (umbra) of the Moon. The sky will then be as dark as dusk.
• Partial eclipse: occurs when the Earth, Moon and Sun are not actually in a straight line. At that time, the Moon only partially blocked the Sun.
• Annular solar eclipse: Appears when the Moon is farthest from Earth. The farther it is from Earth, the smaller the Moon appears, so that it does not completely obscure the Sun, but just as a small disk placed above the larger disk behind the Sun. This type of eclipse creates a ring-like outline around the Moon.

From left to right, three types of eclipses: partial, total and annular. Source: whenistheexteclipse

How will the solar eclipse of December 26, 2019 unfold?

The December 26 solar eclipse is an annular solar eclipse, but only a partial eclipse can be seen in Vietnam. This annular eclipse will begin in Saudi Arabia, move over southern India, northern Sri Lanka, parts of the Indian Ocean and Indonesia before ending in the Pacific Ocean. The partial eclipse will appear over most of Asia and northern Australia.

Simulate the trajectory of the Moon’s shadow on Earth during this eclipse. Source: Time and date

In Vietnam, people in the south will see a partial eclipse with a higher maximum coverage rate than people in the north. Concretely, in the South, the coverage rate can go up to 67%, while in the North from 30% to less than 40%.

The table below lists the eclipse progression for 5 major cities in Vietnam. You can check the progress of the eclipse and the maximum coverage rate for you via the two websites Time&Date and In-the-sky.

(Nguồn: time and date, in the sky)

Partial solar eclipse behind the Empire State Building in New York, USA, 2013. Author: Chris Cook

How to observe the eclipse safely?

NASA recommends not staring at the Sun with bare eyes or using regular sunglasses and goggles. Sunglasses can reduce the amount of visible light, but cannot block intense ultraviolet rays.

More dangerously, absolutely do not view the Sun through viewing equipment such as binoculars or telescopes without the proper filters, as focused sunlight can burn the retina in a fraction of a second.

The safe way to observe a solar eclipse is to make a small pencil-sized hole in a piece of paper or cardboard, then let sunlight shine through the hole onto a temporary screen like piece of paper. The image displayed on the viewing screen is temporarily safer for your eyes.

More professional you can find buy eclipse glasses (eclipse glasses) – a compact viewing device that looks like sunglasses but is able to block harmful radiation from the sun. For binoculars or telescopes, you need to attach a specialized light filtering device called solar filter. You can refer to buy at the Association shop: https://deepsky2000.net/cuahang/danh-muc/do-thien-van-hoc-khoa-hoc/

But even so, observing the Sun through a telescope still carries many potential risks, forcing you to be careful throughout the observing process.

Tham khảo: National Geographic, NASA, Earthsky, Study.com, In-the-sky.org

Edited by: Hong Nhung, Thu Huong, Earthgrazer

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