Astronomy Essentials

Annular solar eclipse on June 21, 2020

Three gold rings around black circles, the two on the outside incomplete.
View at EarthSky Community Photos. | Progression into and out of the December 26, 2019, annular solar eclipse, caught from Tumon Bay, Guam, by Eliot Herman of Tucson, Arizona. Thank you, Eliot!

In June 2020, the moon turns new fewer than nine hours after the June 20 solstice. This new moon will sweep right in front of the sun on Sunday, June 21, 2020, to stage an annular – ring of fire – solar eclipse for a narrow but long slice of the world’s Eastern Hemisphere. A much larger swath of Earth will see varying degrees of a partial solar eclipse.

Read more: June 20 marks the middle of an eclipse season

We in the Americas won’t be able to view this solar eclipse at all. It’ll happen during nighttime hours for us on the night of June 20 (early morning of June 21). By the time the sun rises over the Americas on June 21, the eclipse will be long over. Yet, we in the Americas have a slight chance of catching a very young moon – an exceedingly slim crescent, visible only shortly after sunset – on the evening of June 21.

Read more: Young moon after sunset June 22, 23 and 24, 2020.

Also, if the weather holds in various parts of Africa and Asia, it’ll be possible to watch the eclipse online via the Virtual Telescope Project. Gianluca Masi of Virtual Telescope is putting together an international team of observers along various parts of the eclipse path. Note that, for observers in the Americas, the eclipse will take place during the night of June 20. See the poster below, and find details of Virtual Telescope’s eclipse livestream here.

A Virtual Telescope Project poster advertising the June 21, 2020, annular solar eclipse.
The Virtual Telescope Project live feed of the June 21 annular solar eclipse will happen during the night of June 20, 2020, for us in the Americas. The feed will start on June 21 at 05:30 UTC (June 21 at 1:30 a.m. EDT and 12:30 a.m. CDT; June 20 at 11:30 p.m. MDT and 10:30 p.m. PDT; translate UTC to your time).

If you are watching the eclipse in your sky, proper eye protection must be used throughout the entire June 21 solar eclipse. That’s because an annular eclipse is, essentially, a partial eclipse. Like a total eclipse of the sun, the new moon will move directly in front of the sun. Unlike a total solar eclipse, the new moon during an annular eclipse is too far away to cover the solar disk completely. At mid-eclipse, an annulus – or thin ring – of the sun’s surface will surround the new moon silhouette. Important reminder: No matter where you are, use proper eye protection at all times during the June 21 solar eclipse!

Read more: Top 7 tips for safe solar eclipse viewing

Diagrams showing moon in different positions between Earth and sun, casting shadows.
A = total solar eclipse, B = annular eclipse C = partial solar eclipse.

We refer you to the worldwide map and animation below. The long, skinny annular eclipse path in red will swing a solid 1/3 the way around the world, but spans only 53 miles (85 km) at its widest point. Although the entire annular eclipse on a worldwide scale lasts for about 3 3/4 hours, the maximum length of the annular eclipse at any one place is only 1 minute and 22 seconds.

The annular eclipse starts at sunrise in Africa, and then – some 3 3/4 hours later – ends at sunset over the Pacific Ocean. Greatest eclipse will take place at the border of India, Nepal and China. There, the path width shrinks to a minimum of 13 miles (21 km) with annularity lasting a scant 38 seconds.

View an interactive map of the annular eclipse path via Hermit Eclipse

World globe with red line curving from Africa through Middle East, Asia, and Pacific Ocean.
The long yet skinny red path of the annular eclipse starts at sunrise in Africa, and then, about 3 3/4 hours later, ends at sunset over the Pacific Ocean. A much greater swath of the world is in a position to watch a partial solar eclipse. The numbers from 0.20 to 0.80 refer to eclipse magnitude (the portion of the solar diameter covered over by the moon). Image via Fred Espenak/ NASA GSFC.
World globe showing animated shadow moving across Eastern Hemisphere.
The eclipse starts at sunrise in Africa and ends at sunset over the Pacific Ocean. The tiny black dot depicts the annular eclipse while the much larger gray circle represents the area of the partial solar eclipse.

On a worldwide scale, the partial solar eclipse starts about one hour before the annularity first begins, and ends about one hour after the annular eclipse comes to an end. Here are the eclipse times on a worldwide scale in Universal Time (UTC):

Partial solar eclipse first begins: 03:46 UTC on June 21, 2020
Annular eclipse first begins: 04:48 UTC on June 21, 2020
Greatest or maximum eclipse: 06:40 UTC on June 21, 2020
Annular eclipse finally ends: 08:32 UTC on June 21, 2020
Partial solar eclipse finally ends: 09:34 UTC on June 21, 2020

Local eclipse times for your part of the world

To find out the local eclipse times for your time zone (no conversion is necessary):

Search for a location via TimeandDate.com eclipse map

Eclipse times for hundred of cities via EclipseWise.com

Why is the annular eclipse so short at greatest eclipse?

Along the annular eclipse path, the duration of annularity is greatest at the path’s beginning (just after sunrise) and ending (just before sunset). The duration is the least at the “greatest” eclipse (at and near noon).

The annular eclipse is 1 minute 22 seconds at the beginning of the eclipse path, and 1 minute and 17 seconds at the end. Midway through the path, at the greatest eclipse, the annular eclipse is only 38 seconds long.

Keep in mind that when the moon is nearer the horizon, it is farther away from where you reside on the Earth’s surface than when the moon is high overhead. Because the moon is relatively close to Earth while the sun resides so far away, the apparent size of the moon changes appreciably during the day whereas the sun’s apparent size does not.

Two circles labeled Earth and moon with two stick figures on the Earth circle.
Illustration via Phil Plait. Phil goes on to explain, “The guy at the top of the Earth in the diagram sees the moon on his horizon, and the guy on the side of the Earth sees it overhead. But you can tell the distances aren’t the same: the moon is closer to the guy who sees it as overhead (by an amount roughly equal to the Earth’s radius).”

If this annular eclipse takes place near the horizon, at early morning or late afternoon, then the smaller moon takes more time to cross the solar disk, resulting in a longer annular eclipse.

On the other hand, if the annular eclipse takes place at or around noon, the closer and larger moon takes less time to cross the solar disk, resulting in a shorter annular eclipse.

Exactly six lunar months (six new moons) after this annular eclipse, there’ll be a total eclipse of the sun on December 14, 2020. The new moon will be closer (and therefore larger) than during the June 2020 annular eclipse, so it’ll be a total solar eclipse instead. Yet, the moon will still be more distant (and smaller) at the beginning and the end of the worldwide path of the total solar eclipse, and closer (and larger) at the middle of the path. So it’ll be a shorter total solar eclipse at the beginning and ending of the eclipse path, but a longer total solar eclipse near the middle.

Four columns of dates and times.
The moon phases in the year 2020 via AstroPixels. A = annular solar eclipse, T = total solar eclipse, and n = penumbral lunar eclipse. The year 2020 has 13 full moons, two of which take place in the month of October.

Bottom line: If you live in the world’s Eastern Hemisphere, you might be in a position to watch the annular solar eclipse on June 21, 2020. If so, please remember to use proper eye protection. Eclipse times, links and viewing charts here.

Posted 
June 19, 2020
 in 
Astronomy Essentials

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