Astronomical event: Solar Eclipse 2021

26 May 2021

OSR blog post

Discover the solar eclipse of June 2021. Find out exactly what a solar eclipse is, why it takes place and how you can best view the solar eclipse in 2021.

What is a solar eclipse?

A solar eclipse is the moment when the Earth is engulfed by the shadow of the Moon. The shadow of the Moon blocks the sunlight. A solar eclipse only occurs when the Sun, Moon and the Earth are all aligned and when it is a new moon. This alignment is only the case when it is the so-called ‘eclipse season’. This is the moment when the Sun is close to either the ascending or descending node of the Moon.

In ancient times, solar eclipses were associated with supernatural causes and regarded as bad omen. These days, we know an eclipse is a natural phenomenon and that there is nothing to worry about.

Different types of solar eclipses

There are four different types of eclipses: a total, an annular, a hybrid and a partial eclipse. 

  1. A total eclipse occurs when the Moon completely blocks out the light of the Sun. 
  2. An annular eclipse occurs when the Sun and Moon are exactly in line with the Earth, but the apparent size of the Moon is smaller than that of the Sun. If this occurs, the dark disk of the Moon is surrounded by the bright ring of the Sun. 
  3. A hybrid eclipse shifts between a total and annular eclipse. At certain points on the surface of Earth, it appears as a total eclipse, whereas at other points it appears as an annular eclipse. Hybrid eclipses are comparatively rare. 
  4. Finally, a partial eclipse occurs when the Sun and Moon are not exactly in line with the Earth and the Moon only partially obscures the Sun. Partial eclipses are virtually unnoticeable in terms of the Sun’s brightness, as it takes well over 90% coverage to notice any darkening at all. Even at 99%, it would be no darker than twilight.

How often does a solar eclipse occur?

The event of a total solar eclipses happens rarely. Although they occur somewhere on Earth every 18 months on average, it is estimated that they recur at any given place only once every 360 to 410 years, on average. So when you’re in luck: make sure to view this rare  event!

How long does a solar eclipse last?

A total eclipse only lasts a few minutes at any location, because the Moon is continuously moving. A total eclipse can never last more than 7 minutes and 32 seconds. However, this duration changes over the millennia and is currently decreasing because the Moon is slowly spinning away from the Earth and relocating itself.

Viewing the solar eclipse in 2021

Even when solar eclipses do occur, they are not visible to the whole world. On Thursday the 10th of June 2021 the annular solar eclipse can be seen from Canada, Greenland and Russia. The annular phase will last for a maximum of 3m51s at the point of greatest eclipse.

At the same time a partial eclipse will be much more widely visible from countries like the United States, China and countries in Scandinavia.

Please be aware that viewing the Sun during partial and annular eclipses requires special eye protection, or indirect viewing methods. This is to avoid eye damage. One way to safely view the solar eclipse is to use appropriate filtration to block the harmful part of the Sun’s radiation. 

Please be aware: Sunglasses do not make viewing the Sun safe. Only properly designed and certified solar filters should be used for direct viewing of the Sun’s disk!

Discover the astronomical event of June!

This year Canada, Greenland and Russia are lucky in being able to view an annular solar eclipse, which won’t occur at the same location again in about 360 to 410 years! If you’re located in the northern hemisphere you may be able to view a partial eclipse. Wherever you are, make sure to enjoy the eclipse season! Want to see more of the night sky after the solar eclipse?

Download the OSR Star Finder app!