EclipseGeeks - Solar Eclipses and Lunar Eclipses


All you ever wanted to know about eclipses and other celstial bodies

Everything you need to know about a Supermoon / Perigee Full Moon

Supermoons are extraordinarily quite ordinary.


Supermoons are quite ordinary. A so called supermoon is nothing more than when a Full Moon that coincides when at perigee (nearest distance to Earth. Any Full Moon low on the horizon will look impressive, but once high in the sky, as for size, you would not easily be able to see much – if any – difference to Full Moon at apogee (most distance form Earth). They do however appear to be bright, but again a lot has to do with the atmosphere and clarity of the sky


It can be impressive when the Moon is viewed close to the horizon, and it is very much worthwhile going outside to take a look,  However, once the Moon is high in the sky (at its highest zenith), and free of any Earth buildings, trees, hills or mountains; there is no reference to gauge it against and its apparent size will look little different to a normal Full Moon. The difference in its apparent size compared to a normal Full Moon is negligible and is much more difficult to detect.

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Super Moon - Perigee Full Moon, 23rd June 2013

Supermoon - Perigee Full Moon.


image credit; Andrea Tikki Bond


Crescent Beach, British Columbia, Canada 

A superb photograph. Super Moon framed by trees, Crescent Beach, British Columbia, Canada. (hand-held 70-300m lens) Check out her wonderful photographs of nature on Click on image to enlarge.

Flickr; Claire Stephan: gks18

Supermoon - Perigee Full Moon, Queensland, Australia.

Super Moon, Perigee Full Moon, 23 June 2013, Queensland, Australia. A wonderful image of the Perigee Full Moon.

Click on image to enlarge.

Supermoon – Perigee Full Moon, and background stars.

Perigee Full moon

(Hand-held 300m lens) See more of Gail Stephen’s wonderful photographs on Flickr: gks18. Click on image to enlarge.


Credit image, Gail Stephan. Claire Stephan,Flickr

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Photo credit; Andrea.

credit image Gail Stephan

A Super Moon is known by astronomers  technically as a:

Perigee-Syzygy of the Earth-Moon-Sun system.


Perigee means: closest approach to The Earth.

Apogee means: farthest distance from The Earth.

Syzygy means:  an alignment of three celestial objects.


For example: A syzygy in the Sun-Earth-Moon system occurs at the time of a Full Moon and New Moon.



A New Moon at perigee cannot be observed because the phenomena occurs during the daytime,  and although astrologers classify it as a Supermoon and may hold value to those who are interested in Zodiac Star Signs, to astronomers a New Moon Supermoon holds minimum value, because it cannot be observed.


How much bigger is a Supermoon compared to a normal Full Moon? 


How much brighter is a Supermoon compared to a normal Full Moon?

A Perigee Syzygy Full Moon, or Super Moon is approximately 14% larger than a Full Moon at apogee (farthest away) and about 30% brighter. A Supermoon compared to an average Full Moon looks about 7% larger and about 16% brighter.


What is an astronomers technical name for a supermoon?

The technical name of a Super Moon used by astronomers is: a perigee-syzygy of the Earth–Moon–Sun system.


Why do we call it a Supermoon?

The term Supermoon is not astronomical, but originates from astrology by an astrologer (not an astronomer) named Richard Nolle who first coined the word ‘Supermoon’ and defined both a Full Moon and New Moon as a Super when the Moon is within 90% of its perigee with the Earth


Occasionally, a 'Full Moon' Super Moon coincides with Total Lunar Eclipse. The most recent date of this was 28th September 2015, and the next will be on 8th October 2033. In a similar way a 'New Moon' Supermoon sometimes coincides with a Solar Eclipse.


Exaggerated and Hyperbole Claims about a Supermoon

When supermoons are in the news, you might hear from some sources exaggerated statistics about the size and brightness of a Supermoon, however, although we encourage you to look at the Moon, eclipses, and other astronomical phenomena as and when they occur, a Supermoon high in the sky, looks pretty much like any other Full Moon. You may also hear of claims and associations that a Supermoon may increase the risk of physical events such as earthquakes and volcanic eruptions, but there is no evidence that Supermoons are the cause of such events.

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What's in a name... ? a perigee syzygy Full Moon, or a perigee-syzygy of the Earth–Moon–Sun system; or Supermoon.

The term Supermoon is not generally used within the astronomical community, whom instead usually prefer the term, perigee-syzygy or perigee Full/New Moon.


However, with the increase of social media the term ‘Supermoon’ has become widespread and is in common use amongst many people. After all it is a lot easier to say ‘Supermoon’ than to say the full technical name; ‘a perigee-syzygy of the Earth–Moon–Sun system’ so it’s no wonder why the term ‘Supermoon’ has become popular. So call it what you prefer, a Supermoon, a perigee syzygy Full Moon, a perigee Full/New Moon, or a perigee-syzygy of the Earth–Moon–Sun system.


Supermoon Effect on Tides on Earth:

The effect that the Sun and the Moon have on the oceans of the Earth are greatest when there is either a Full or New Moon. The tidal force of Earth’s oceans by a Supermoon at perigee has a slightly stronger effect than a normal Full or New Moon, but the gravitational force is relatively weak and compared to a normal Full or New Moon, may cause tides to rise by an extra inch or two, (2cm or slightly more).  


A reminder about the etymology of the name: Supermoon.

As previously mentioned, astrologer Richard Nolle also described a New Moon as a Supermoon when it is within 90% of its perigee (closest distance) with the Earth. However, as many of you may already know, a New Moon is in the sky during daytime; it rises in morning; is in the sky during the day, and sets at around dusk; and unless there is a Solar Eclipse, a New Moon does not show itself during the height of daytime.


Natural disasters connections (or not) and Supermoons

There is no concrete evidence of interrelationships between Supermoons and major Earthquakes or tsunamis. Irrespective of evidence the press and TV sometimes make claims and speculations that Supermoons and natural disasters are linked.


Connections made by the media between the occurrence of Supermoons and natural disasters including the 2004 Indian Ocean earthquake and tsunami; the 2011 earthquake and tsunami in Tōhoku, Japan; and the large 7.5 magnitude earthquake centred approximately 9 miles (15 km) north-east of Culverden, New Zealand on 14th November  2016, none of which have been scientifically proven.

A Supermoon and a Full Moon at apogee;

side by side comparison.


The apparent size of a Supermoon compared to a normal average Full Moon isn’t that much.

In a side-by-side comparison, a difference in size can be spotted, but when the Moon is on its own high in the sky, judging a difference in size between one Full Moon and another becomes much more challenging.


(To enlarge: click on 'perigee / apogee' photo.)

Supermoon compared to Full Moon at apogee.

The Moon orbits Earth in an elliptical path; average distance is approximately:

238,00 miles (382,900 km).

The diagram on the left is an example of the Moon’s orbit around the Earth. Perigee is when the Moon is closest to Earth and apogee when the Moon is at its farthest distance from Earth.


What is a Super Moon? A Supermoon is a Full or New Moon at perigee (nearest approach to Earth.) Many astronomers prefer using the term: a perigee Full Moon as opposed to a supermoon.


When does a Supermoon occur? A Super Moon occurs at Full or New Moon when it coincides with its closest approach (perigee) to the Earth or when it is at, or within 90% of its apogee with Earth (223,000 miles/359,000 km).


A Full Moon at perigee produces the largest apparent diameter of the lunar disc as viewed from Earth.


Qestions on a Super Moon answered here:

Super Moon Facts and information

A Supermoon is in fact Extraordinarily quite Ordinary

What is a Super Moon?


Why do we call it a Supermoon?

How much bigger and brighter is a Supermoon

compared to a normal Full Moon?


What is an astronomer’s technical name

for a supermoon?

What effects does a Super Moon have on Tides on Earth?  


Are Natural disasters connected with Supermoons?

A brief introduction to a Super Moon:

The main things to know about a Super Moon.

Separating Super Moon Facts from Super Moon Myths.


The term Super Moon was first thought up in 1979 by astrologer (not astronomer) Richard Nolle. He defined a Super Moon as a New or Full Moon at or near (within 90% of) its closest approach to Earth in a given orbit.   The technical name of a Super Moon used by astronomers is: a perigee-syzygy of the Earth Moon Sun system. It can also be referred to as a perigee syzygy Full Moon.


Supermoons are extraordinarily quite ordinary and Supermoons are not rare.  Any rising Full Moon close to the horizon will look large and impressive. A perigee-syzygy Full Moon (Supermoon) as about 14% larger than a Full Moon at apogee (farthest away from Earth) and about 30% brighter; and a Supermoon compared to an average Full Moon looks about 7% larger and about 16% brighter.


There is not any scientific evidence that Supermoons cause Earthquakes or volcanoes. A Super Moon will not fill the sky. When a Supermoon is high in the sky it is difficult to tell the difference between a Supermoon or a normal Full Moon.


New Moon Supermoons:  2017 to 2021:

Dates, Time, and Distance.

Perigee-Syzygy of Earth-Moon-Sun system: 2017 to 2021


This calendar shows 'New Moon' Supermoons.



2017: Thursday 25th May: New Moon 19:44 GMT/UT |

Perigee: Friday 26th May, 01:24 GMT/UT | Distance: 221,959 miles /357,209 km


2017: Saturday 24th June: New Moon 02:31 GMT/UT |

Perigee: Friday 23rd June, 10:50 GMT/UT | Distance: 222,411 miles  / 357,937 km


2018: Friday 13th, July: New Moon 02:48 GMT/UT |

Perigee: Friday 13th July, 08:30 GMT/UT |Distance: 222,097 miles /357,431KM. Solar eclipse.


2018: Saturday 11th August: New Moon 09:58 GMT/UT | Perigee: Friday 10 August, 18:06 GMT/UT | Distance: 222,327 miles /358,082km. Solar Eclipse.


2019: Saturday 28th September: New Moon 18:26 GMT/UT | Perigee: Saturday 28h September, 02:28 GMT/UT | Distance:  357,802km


2020: Friday 16th October: New Moon 19:31GMT/UT |

Perigee: Friday 16th October: 23:48 GMT/UT | Distance: 221,774 miles /356,912km


2020: Sunday 15th November: New Moon 05:07 GMT/UT | Perigee: Saturday 14 November 11:49 GMT/UT | Distance: 222,350  / 357,838 km.


2021: Saturday 04th December: New Moon 07:43 GMT/UT | Perigee: Saturday 04th December, 10:02 GMT/ UT. | 221,700 miles/356,793 km

Super Moons 2017 to 2021: Dates, Time, and Distance.

Perigee-Syzygy of Earth-Moon-Sun system: 2017 to 2021


This calendar shows 'Full Moon' Supermoons.


These dates show the Super Moon at maximum Full Moon, plus the time and date when The Moon reaches its Perigee (closest approach) to Earth.


2017: Sunday 3rd December: Full Moon 15:47 GMT/UT | Perigee: Monday 04th December, 08:43 GMT/UT: Distance: 222,137 miles/ 357,495km.


2018: Tuesday 2nd January:  Full Moon 02:24 GMT/UT | Perigee: Monday 01st January,     21:56 GMT/UT. Distance:  221,559 miles/ 356,565km


2019: Monday 21st January: Full Moon 05:16 GMT/UT | Perigee: Monday 21st January,19:59 GMT/UT. Distance:  222,043 miles/  357,344km


2019: Tuesday 19th February: Full Moon 15:53 GMT/UT | Perigee: Tuesday 19th February, 09:07 GMT / UT. Distance: 221,681 miles/  356,761km


2020: Saturday 09th February: Full Moon: 09th Feb 07:34 GMT/UT | Perigee: Monday 10th February, 20:32 GMT/UT. Distance:  225,234 miles /362,479km (not all astronomers define this Moon as a Supermoon).        


2020: Monday 9th March: Full Moon 17:48 GMT/UT | Perigee: Tuesday 10th March, 06:34 GMT / UT. Distance:     221,905 miles/  357,122 km


2020: Wednesday 8th April: Full Moon 02:35 GMT/UT | Perigee: Tuesday 07th April, 18:10 GMT / UT. Distance: 221,772 miles/ 356,908km


2020: Thursday 07th May: Full Moon 10:46  GMT/UT | Perigee: Wednesday 06th May, 03:05 GMT /UT. Distance:  222,064 miles/ 357,378km


2021: Saturday 4th December: Full Moon 07:43 GMT/UT | Perigee: Saturday  04th December, 10:02 GMT/UT. Distance: 221,700 miles/

To enlarge: click on Earth - Moon diagram


The Moon is moving away from Earth at 1.48 inches/3.78cm a year. It’s about the same speed at which our fingernails grow.