Annular Eclipses of the Sun

occurrence - annular eclipses seen


Introduction

Annular Eclipses are a type of solar eclipse where the Moon is too far from the Earth to cover the Sun completely, leaving a ring (or "annulus") of Sunlight visible.


Occurrence and Types of Eclipses

There are four types of solar eclipses.

When the Moon's shadow misses the Earth but passes very close to it, only a Partial eclipse is visible. These types of eclipse tend to be visible away from the tropics.

When the Moon's shadow hits the Earth and the Moon is close to the Earth, then a Total eclipse is visible along the narrow path of Totality. (A Partial eclipse occurs on either side of the path of Totality). For a Total eclipse, the Moon can appear to be as much as 6.5% larger than the Sun. The maximum duration of Totality is 7m 31s. Eclipses over seven minutes long are rare; only three occurred during the 20th Century and none will happen in the 21st Century. Longer eclipses tend to occur nearer the tropics.

When the Moon's shadow hits the Earth but the Moon is far from the Earth, it will not be large enough to cover the Sun completely. A ring of Sun remains around the Moon. This ring-shaped partial eclipse is called an Annular Eclipse (from annulus the Latin for ring). At its most extreme, the Moon can be 10.9% too small to cover the Sun. The maximum duration of Annularity is 12m 30s.

A Hybrid Eclipse is where the Moon is at such a distance that the eclipse is Annular in some areas and Total in other areas. The duration is usually very short for these types of eclipses.

In any calendar year there must be TWO solar eclipses and there can be as many as FIVE. Slightly more will be Annular than Total. The table below shows all Solar Eclipses occurring between 2010 and 2030.

Year Total Annular Hybrid Partial
2010 1 1    
2011      4
2012 1 1    
2013   1 1  
2014   1   1
2015 1     1
2016 1 1    
2017 1 1    
2018       3
2019 1 1   1
2020 1 1    
2021 1 1    
2022       2
2023   1 1  
2024 1 1    
2025       2
2026 1 1    
2027 1 1    
2028 1 1    
2029       4
2030 1 1    
Totals 13 15 2 18


The Saros

All types of eclipses occur when the Sun, Moon and Earth are in almost exact alignment. Their motions are such that they almost repeat after approximately 18 years 11 days and 8 hours. This period is known as the Saros.

If an eclipse occurs, a similar one will happen after one Saros. The long total solar eclipse eclipse of 11 July 1991 is followed by another on 22 July 2009. The extra 8 hours of the Saros period allows the Earth to spin a third of its daily rotation, a turn of 120 degrees. This means that the 1991 eclipse was total in the Eastern Pacific and the Americas but the 2009 eclipse was total in Eastern Asia and the Western Pacific, 120 degrees to the West. Eclipses related in this way are said to belong to a Saros Series.

The repeat of the Sun, Moon and Earth every Saros is not exact, however. The path of totality moves either north or south. Given enough time the location of the eclipse slowly drifts and will eventually leave the Earth. Each eclipse belongs to a Saros Series which is given a number. As an example we will examine the properties of Saros Series number 139.

Saros Series 139 began on 17 May 1501 with a small partial eclipse visible over one of the northern polar regions. The Moon's umbra missed the Earth but passed close enough for a small partial eclipse (covering 9.1% of the Sun) to be visible. The next eclipse in the Saros Series occured 18 years 11 days and 8 hours later. The Moon's umbra passed closer to the Earth than the previous eclipse but still not close enough to produce a total eclipse. It was a slightly bigger partial eclipse (23.5%) at the same pole on 28 May 1519.

Each successive eclipse was partial but of increasing magnitude. Eventually after seven partial eclipses, the umbra hit the Earth producing a hybrid eclipse around the same northern polar region on 11 August 1627. The duration of totality was very short: 0m 01s. The type of eclipse depends on how far the Moon is from the Earth and at this time the Moon was too far to make a purely total eclipse.

Saros number 139 continued with each successive eclipse moving closer to the equator and with the Moon moving closer to the Earth. This produced a series of 12 hybrid eclipses, the final one on 9 December 1825. The duration of totality was 1m 34s. The next eclipse (21 December 1843) was total along its entire path (duration 1m 43s). The eclipses continued moving south towards the equator and getting longer.

On 18 March 1988, the 28th eclipse of the series occured in the Pacific Ocean. A totality of 3m 22s (from a maximum of 3m 46s) was observed by Kryss in the Philippines. The 29th eclipse of the series occured on 29 March 2006 across Africa and Eurasia and was seen by Kryss and Talaat from Turkey.

On 13 June 2132 the middle eclipse of Saros 139 will occur. The duration will be 6m 55s. After this the successive eclipses will cross into the southern hemisphere. They will continue to increase in length until 16 July 2186 when totality will last for 7m 29s, only two seconds short of the maximum theoretical length. This Saros will produce five eclipses longer than seven minutes.

The total eclipses continue to move south but now decrease in length. The final total eclipse of the series will occur on 26 March 2601. After that there will be nine partial eclipses in the southern polar regions ending with a small partial eclipse of 5.8% ocurring on 3 July 2763.

Saros 139 began on 17 May 1501 and will end on 3 July 2763. It will last 1262 years and produce 71 eclipses comprising 43 totals, 12 hybrids and 16 partials.

As of 2020 there are 40 solar Saros series active. The latest (Saros 156) began on 1 July 2011. Saros 117 will end on 3 August 2054.


Annular Solar Eclipses Seen / Experienced

This table summarises the Annular Eclipses of the Sun that have been seen or experienced by Kryss Katsiavriades.

Eclipse
Number
Eclipse
Click here to read report and see photos
Date and Location
Red for totality completely clouded out
Duration
of
Totality
Length
of
Trip
Countries
Visited
Eclipse country in bold
1
Qatar 2019
26 December 2019 : Sealine Beach south of Doha, Qatar.

2m 41s
Cloud
5
weeks
Jordan
Israel / Palestine
Kuwait
Qatar
Annular Eclipse Successes   
0 out of 1
Duration of Anularity Seen   
0m 0s
Duration of Anularity Not Seen   
2m 41s


KryssTal Related Pages

The total solar eclipses seen by Kryss Katsiavriades.


External Eclipse Links

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Interactive Eclipse Maps
by Xavier M. Jubier

Live@Exploratorium
A fascinating eclipse and astronomy site with excellent historical accounts of eclipses and contributions from eclipse chasers.

Eclipse Glasses
Small or large amounts of CE approved eclipse glasses as used by the BBC.

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