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| Astronomy Essentials | Space on Oct 02, 2014

How many solar and lunar eclipses in one calendar year?

Each calendar year has at least four eclipses – two solar and two lunar. Most years have four, but five, six or even seven eclipses are also possible.

Eclipses of the sun and moon excite more interest than any other event in astronomy. And no wonder. It’s a thrill to go outdoors, witness these grand spectacles of nature, and stand in line with the sun, Earth and moon. How rare are these events? Follow the links below to learn more about lunar and solar eclipses.

How many solar or lunar eclipses occur in one calendar year?

Four eclipses in the year 2014

Is it possible to have three eclipses in one month?

Some cool things about years with seven eclipses.

Is it possible to have eight eclipses in one year?

Total eclipse of Blood Moon on night of October 7-8

North Americans see partial solar eclipse on October 23

Composite total solar eclipse Aug. 1999 by Fred Espenak.

A total solar eclipse in August, 1999 by Fred Espenak. It’s a combination of 22 photographs that were digitally processed to highlight faint features. The outer pictures of the sun’s corona were digitally altered to enhance dim, outlying waves and filaments. The inner pictures of the usually dark moon were enhanced to bring out its faint glow from doubly reflected sunlight. This image was NASA’s Astronomy Picture of the Day for April 8, 2001.

This is what a total eclipse looks like.  This is the total eclipse of October 27, 2004 via Fred Espenak of NASA, otherwise known as Mr. Eclipse.  Visit Fred's page here.

This is what a total eclipse of the moon looks like. This is the total lunar eclipse of October 27, 2004 via Fred Espenak of NASA, otherwise known as Mr. Eclipse. Visit Fred’s page here.

View larger A total solar eclipse can happen only at new moon, when the moon passes directly between the sun and Earth.  Why aren't there eclipses at every full and new moon?

View larger A total solar eclipse can happen only at new moon, when the moon passes directly between the sun and Earth. Why aren’t there eclipses at every full and new moon?

View larger A lunar eclipse happens when the Earth, sun and moon align in space, with Earth in the middle. Why aren't there eclipses at every full and new moon?

View larger A lunar eclipse happens when the Earth, sun and moon align in space, with Earth in the middle. Why aren’t there eclipses at every full and new moon?

How many solar or lunar eclipses occur in one calendar year? The answer very much depends on the year. One calendar year has a minimum of four eclipses – two solar eclipses and two lunar eclipses. Most years – such 2014 – have only four eclipses, although you can have years with five eclipses (2013, 2018 and 2019), six eclipses (2011 and 2020) or even as many as seven eclipses (1982 and 2038).

It is rare to have seven eclipses in one calendar year, however. The last time was 1982 and the next time will be 2038. Any calendar year presenting the maximum seven eclipses must have the first eclipse coming in early January, so as to leave enough room for the seventh eclipse to take place in late December. Then the middle part of the year has to stage three eclipses within the framework a single lunar month – the period of time between successive new moons or full moons. The lunar (or synodic) month has a mean duration of 29.53059 days.

Four eclipses in the year 2014

April 15: total lunar eclipse
April 29: annular solar eclipse
October 7-8: total lunar eclipse
October 23: partial solar eclipse

Total lunar eclipse of Hunter’s Moon on night of October 7-8

Is it possible to have three eclipses in one month? It’s quite rare to have three eclipses in one calendar month. The last time it happened was in the year 2000, and the next time won’t be until the year 2206!

It’s more common to have three eclipses within one lunar month. A lunar month refers to time period between successive new moons, or successive full moons. The last time three eclipses happened in a lunar month was in the year 2013. The next time will be 2018.

Three eclipses in a month can be either two solar eclipses and one lunar eclipse, or two lunar eclipses and one solar eclipse. If the first of three eclipses is a solar eclipse, then the third eclipse will be solar and the middle one lunar. If, on the other hand, the first eclipse is lunar, the third will be lunar and the middle one solar. That’s because a solar eclipse happens within one fortnight (two weeks) of a lunar eclipse – and vice versa.

Read more: Three eclipses in one month

Some cool things about years with seven eclipses. Notice the two-week separations accompanying the eclipse pairs and eclipse triplets in the lists below. We list the seven eclipses for the years 1982 (4 solar/3 lunar) and 2038 (3 solar/4 lunar):

1982 (Seven eclipses: 4 solar/3 lunar) 2038 (Seven eclipses: 3 solar/4 lunar)
Jan 9 lunar eclipse Jan 5 solar eclipse
Jan 25 solar eclipse Jan 21 lunar eclipse
Jun 21 solar eclipse Jun 17 lunar eclipse
Jul 6 lunar eclipse Jul 2 solar eclipse
Jul 20 solar eclipse Jul 16 lunar eclipse
Dec 15 solar eclipse Dec 11 lunar eclipse
Dec 30 lunar eclipse Dec 26 solar eclipse

A year containing seven eclipses can harbor a maximum of five solar or five lunar eclipses. In this scenario, two lunar months contain three eclipses each (for a total of six eclipses), and a single eclipse happens in late December or early January.

1935 (Seven eclipses: 5 solar/2 lunar) 2132 (Seven eclipses: 2 solar/5 lunar)
Jan 5 solar eclipse Jan 2 lunar eclipse
Jan 19 lunar eclipse
Feb 3 solar eclipse May 30 lunar eclipse
Jun 13 solar eclipse
Jun 30 solar eclipse Jun 28 lunar eclipse
Jul 16 lunar eclipse
Jul 30 solar eclipse Nov 23 lunar eclipse
Dec 7 solar eclipse
Dec 25 solar eclipse Dec 22 lunar eclipse

Seven eclipses occur in a minimum of 12 lunar months (about 354.37 days). Given that the calendar year is only about eleven days longer than 12 lunar months, the first of the seven eclipses has to come in early January for the seventh eclipse to occur before the end of the year.

A solar eclipse always happens within one fortnight (two weeks) of a lunar eclipse – or vice versa. Yet it’s still possible that eclipses separated by a fortnight can occur in different calendar years. For instance, the solar eclipse at the end of the year on December 25, 1935, was followed by a lunar eclipse one fortnight (two weeks) later on January 8, 1936. In another example, the lunar eclipse at the beginning of the year on January 2, 2132, will come one fortnight after the solar eclipse of December 19, 2131.

Can there be eight eclipses in a calendar year? No. Eight eclipses occur in a minimal period of 12.5 lunar months (about 369 days), making it impossible for eight eclipses to fit within the framework of a calendar year (365 or 366 days).

Although a minimum of two lunar eclipses happen every year, one or both could be penumbral, meaning the moon never enters the Earth's dark umbral shadow. In the year 2016, both lunar eclipses will be penumbral. The diagram illustrates the penumbral lunar eclipse of March 23, 2016.

Although a minimum of two lunar eclipses happen every year, one or both could be penumbral, meaning the moon never enters the Earth’s dark umbral shadow. In the year 2016, both lunar eclipses will be penumbral. The diagram illustrates the penumbral lunar eclipse of March 23, 2016.

Bottom line: Any calendar year has a minimum of four eclipses – two solar and two lunar. Most years have only four eclipses, but depending on the year, it’s possible to have five eclipses, six eclipses or even as many as seven eclipses in one-year’s time.

Why aren’t there eclipses at every full and new moon?

How often do 7 eclipses occur in 365 days?