Supermoon

by Dominic Ford, Editor
Last updated: 29 Jan 2021
Supermoon

Full Moon. Image courtesy of Tom Ruen.

A supermoon is, according to some publications, a full moon or new moon which occurs when the Moon is closer than usual to the Earth.

The term originated among astrologers in the late 1970s, and does not have a precise definition. Although the term has recently begun to be used by stargazers as well as astrologers, in practice a supermoon looks little different from any other moon.

The term first appeared in the Dell Horoscope in 1979, where it was introduced by the astrologer Richard Nolle. In subsequent publications, Nolle has presented various differing definitions of how close the Moon needs to be to the Earth to qualify as a supermoon, and as a result, lists of such events are rarely consistent. These various definitions are summarised in detail by Wikipedia here.

The Moon's elliptical orbit

The Moon orbits the Earth in an elliptical orbit, which means its distance from the Earth changes over time, oscillating with a 27.55-day period, called an anomalistic month. The variation is extremely slight, however: the Moon never comes closer than 362,600 km (perigee), or recedes further than 405,400 km (apogee) – a maximum difference of only 12%. This leads to an extremely slight change in the Moon's apparent size of about 14%.

The chart below illustrates the two extremes of this variation in the size.

The Moon
Full Moon
at perigee
The Moon
Full Moon
at apogee

Even in months without supermoons, the Moon's apparent size subtly changes from week to week, oscillating between these two extremes. The effect goes entirely unnoticed, since the change is so small that it is right at the limit of what even the best human eyesight can perceive.

The only way in which a supermoon is any different from other months is that the date of full moon happens to coincide with when the Moon appears at its largest. In the other months of the year, the Moon's size will fall somewhere between the two extremes shown above on the day of full moon.

For this reason, supermoons are of little interest to stargazers. Anyone who is tempted to rush outdoors to observe one is likely to be disappointed. Indeed, if the Moon does seem to appear abnormally large, this is far more likely to be an optical illusion than anything to do with the Moon's distance from the Earth. This extremely common illusion is called the Moon illusion.

The Moon illusion

Although the angular size of the Moon only changes by a very modest amount in reality, it is very common for the Moon to be perceived as appearing much larger than it really is when it is close to the horizon. This is called the Moon illusion – and is nothing more than an optical illusion. Any photograph will reveal that the Moon is exactly the same size regardless of whether it appears on the horizon or directly overhead.

The reason why we perceive this optical illusion is hotly debated. However, it may explain why some people who go out in the early evening to observe a supermoon may be convinced that the Moon appears unusually large, despite the actual changes in its true size being so small.

Defining a supermoon

As a result of Richard Nolle's multiple inconsistent definitions of what qualifies as a supermoon, various websites produce different lists of such events, based on their own definitions. For example, Sky & Telescope uses the term when the Moon is closer than 358,884 km. TimeandDate.com, meanwhile, uses the term when the Moon is closer than 360,000 km.

Fred Espenak has attempted to interpret Richard Nolle's definitions literally – which leads to a more complicated definition. Espenak compares the Moon's distance on the day of full moon with the distances of its closest approach (perigee) with its furthest recess (apogee) in that same month. The full moon is said to be a supermoon if the Moon's distance on that day is at least ten times closer to its perigee distance than its apogee distance.

Micromoons

A term which has come into even more recent usage is micromoon. This refers to a full moon which occurs when the Moon is close to apogee, and is therefore at its further recess from the Earth. Needless to say, micromoons are of even less observational interest than supermoons.

List of supermoons 1950–2299

The following full moons occur when the Moon is closer than 358,884 km from the Earth:

Date Distance
02 May 1950356902 km
31 May 1950358877 km
19 Jun 1951356913 km
05 Aug 1952357059 km
23 Sep 1953356743 km
22 Oct 1953358882 km
12 Oct 1954358720 km
10 Nov 1954356565 km
29 Nov 1955358377 km
28 Dec 1955356603 km
16 Jan 1957357768 km
14 Feb 1957356599 km
05 Mar 1958357692 km
03 Apr 1958357068 km
23 Apr 1959357757 km
22 May 1959357257 km
09 Jun 1960357694 km
08 Jul 1960357274 km
27 Jul 1961357847 km
25 Aug 1961357374 km
14 Sep 1962357523 km
13 Oct 1962357087 km
01 Nov 1963357151 km
30 Nov 1963357158 km
18 Dec 1964356950 km
17 Jan 1965357448 km
05 Feb 1966356633 km
06 Mar 1966357716 km
25 Mar 1967356860 km
24 Apr 1967358307 km
12 May 1968357003 km
10 Jun 1968358430 km
29 Jun 1969356979 km
28 Jul 1969358441 km
16 Aug 1970357080 km
15 Sep 1970358534 km
04 Oct 1971356720 km
02 Nov 1971358377 km
20 Nov 1972356524 km
20 Dec 1972358775 km
09 Dec 1973358777 km
08 Jan 1974356548 km
27 Jan 1975358158 km
25 Feb 1975356537 km
15 Mar 1976358097 km
14 Apr 1976356976 km
03 May 1977358150 km
01 Jun 1977357111 km
20 Jun 1978358065 km
19 Jul 1978357089 km
07 Aug 1979358176 km
06 Sep 1979357151 km
24 Sep 1980357791 km
23 Oct 1980356840 km
11 Nov 1981357378 km
11 Dec 1981356916 km
30 Dec 1982357151 km
28 Jan 1983357194 km
16 Feb 1984356832 km
17 Mar 1984357439 km
05 Apr 1985357055 km
04 May 1985357975 km
23 May 1986357164 km
21 Jun 1986358038 km
10 Jul 1987357106 km
09 Aug 1987358017 km
27 Aug 1988357161 km
25 Sep 1988358087 km
14 Oct 1989356753 km
13 Nov 1989357933 km
02 Dec 1990356541 km
31 Dec 1990358346 km
19 Jan 1992356551 km
18 Feb 1992358844 km
06 Feb 1993358602 km
08 Mar 1993356531 km
27 Mar 1994358561 km
25 Apr 1994356939 km
14 May 1995358601 km
13 Jun 1995357024 km
30 Jun 1996358493 km
30 Jul 1996356964 km
18 Aug 1997358559 km
16 Sep 1997356987 km
05 Oct 1998358109 km
04 Nov 1998356652 km
23 Nov 1999357655 km
22 Dec 1999356731 km
09 Jan 2001357405 km
08 Feb 2001356992 km
27 Feb 2002357087 km
28 Mar 2002357208 km
16 Apr 2003357306 km
15 May 2003357691 km
03 Jun 2004357381 km
02 Jul 2004357698 km
21 Jul 2005357288 km
19 Aug 2005357648 km
07 Sep 2006357295 km
06 Oct 2006357697 km
26 Oct 2007356838 km
24 Nov 2007357545 km
12 Dec 2008356611 km
10 Jan 2009357968 km
30 Jan 2010356607 km
28 Feb 2010358432 km
19 Mar 2011356577 km
17 Apr 2011358796 km
05 May 2012356955 km
23 Jun 2013356991 km
10 Aug 2014356896 km
27 Sep 2015356879 km
16 Oct 2016358473 km
14 Nov 2016356520 km
03 Dec 2017357983 km
01 Jan 2018356602 km
21 Jan 2019357715 km
19 Feb 2019356843 km
09 Mar 2020357400 km
07 Apr 2020357030 km
26 Apr 2021357616 km
26 May 2021357461 km
14 Jun 2022357656 km
13 Jul 2022357418 km
01 Aug 2023357528 km
30 Aug 2023357341 km
17 Sep 2024357485 km
17 Oct 2024357367 km
05 Nov 2025356978 km
04 Dec 2025357218 km
23 Dec 2026356738 km
22 Jan 2027357644 km
10 Feb 2028356721 km
10 Mar 2028358071 km
29 Mar 2029356681 km
28 Apr 2029358382 km
17 May 2030357029 km
15 Jun 2030358782 km
04 Jul 2031357018 km
02 Aug 2031358653 km
20 Aug 2032356886 km
19 Sep 2032358651 km
08 Oct 2033356829 km
06 Nov 2033358802 km
27 Oct 2034358883 km
25 Nov 2034356446 km
14 Dec 2035358360 km
13 Jan 2036356529 km
31 Jan 2037358080 km
01 Mar 2037356747 km
20 Mar 2038357771 km
19 Apr 2038356902 km
08 May 2039357982 km
06 Jun 2039357284 km
24 Jun 2040357989 km
23 Jul 2040357192 km
11 Aug 2041357820 km
10 Sep 2041357089 km
29 Sep 2042357723 km
28 Oct 2042357094 km
16 Nov 2043357168 km
16 Dec 2043356943 km
03 Jan 2045356918 km
01 Feb 2045357371 km
20 Feb 2046356890 km
22 Mar 2046357753 km
10 Apr 2047356840 km
09 May 2047358014 km
27 May 2048357159 km
25 Jun 2048358355 km
14 Jul 2049357101 km
13 Aug 2049358188 km
01 Sep 2050356931 km
30 Sep 2050358180 km
19 Oct 2051356831 km
18 Nov 2051358329 km
06 Dec 2052356426 km
04 Jan 2053358482 km
25 Dec 2053358786 km
23 Jan 2054356511 km
11 Feb 2055358501 km
13 Mar 2055356705 km
31 Mar 2056358202 km
29 Apr 2056356831 km
18 May 2057358409 km
16 Jun 2057357164 km
05 Jul 2058358378 km
04 Aug 2058357025 km
23 Aug 2059358168 km
21 Sep 2059356896 km
09 Oct 2060358012 km
07 Nov 2060356878 km
27 Nov 2061357409 km
26 Dec 2061356728 km
14 Jan 2063357156 km
13 Feb 2063357151 km
03 Mar 2064357118 km
01 Apr 2064357489 km
20 Apr 2065357059 km
19 May 2065357699 km
Date Distance
07 Jun 2066357349 km
07 Jul 2066357986 km
26 Jul 2067357244 km
24 Aug 2067357783 km
11 Sep 2068357033 km
10 Oct 2068357768 km
29 Oct 2069356888 km
28 Nov 2069357915 km
17 Dec 2070356463 km
15 Jan 2071358076 km
03 Feb 2072356550 km
04 Mar 2072358772 km
23 Mar 2073356719 km
11 Apr 2074358692 km
10 May 2074356813 km
28 Jun 2075357103 km
16 Jul 2076358824 km
14 Aug 2076356916 km
02 Sep 2077358564 km
01 Oct 2077356760 km
20 Oct 2078358348 km
19 Nov 2078356718 km
08 Dec 2079357699 km
06 Jan 2080356566 km
24 Jan 2081357445 km
23 Feb 2081356980 km
14 Mar 2082357401 km
12 Apr 2082357270 km
01 May 2083357334 km
31 May 2083357435 km
18 Jun 2084357596 km
17 Jul 2084357671 km
05 Aug 2085357441 km
03 Sep 2085357434 km
22 Sep 2086357188 km
22 Oct 2086357414 km
10 Nov 2087356998 km
09 Dec 2087357557 km
27 Dec 2088356552 km
26 Jan 2089357721 km
14 Feb 2090356643 km
15 Mar 2090358384 km
03 Apr 2091356787 km
03 May 2091358694 km
21 May 2092356853 km
19 Jun 2092358867 km
08 Jul 2093357100 km
25 Aug 2094356867 km
24 Sep 2094358821 km
13 Oct 2095356682 km
31 Oct 2096358731 km
29 Nov 2096356615 km
18 Dec 2097358042 km
17 Jan 2098356461 km
05 Feb 2099357792 km
06 Mar 2099356863 km
25 Mar 2100357744 km
24 Apr 2100357106 km
13 May 2101357669 km
11 Jun 2101357228 km
30 Jun 2102357902 km
29 Jul 2102357418 km
17 Aug 2103357696 km
16 Sep 2103357146 km
04 Oct 2104357397 km
02 Nov 2104357119 km
21 Nov 2105357161 km
21 Dec 2105357256 km
09 Jan 2107356699 km
07 Feb 2107357418 km
26 Feb 2108356791 km
27 Mar 2108358043 km
15 Apr 2109356911 km
14 May 2109358287 km
02 Jun 2110356949 km
01 Jul 2110358413 km
20 Jul 2111357154 km
19 Aug 2111358546 km
06 Sep 2112356872 km
05 Oct 2112358317 km
24 Oct 2113356660 km
22 Nov 2113358541 km
12 Dec 2114356567 km
31 Dec 2115358432 km
29 Jan 2116356409 km
16 Feb 2117358193 km
18 Mar 2117356797 km
06 Apr 2118358142 km
05 May 2118356992 km
24 May 2119358059 km
22 Jun 2119357073 km
10 Jul 2120358262 km
09 Aug 2120357218 km
28 Aug 2121358001 km
26 Sep 2121356915 km
15 Oct 2122357654 km
13 Nov 2122356882 km
03 Dec 2123357374 km
01 Jan 2124357009 km
19 Jan 2125356900 km
17 Feb 2125357165 km
09 Mar 2126356997 km
07 Apr 2126357749 km
26 Apr 2127357091 km
25 May 2127357931 km
12 Jun 2128357103 km
12 Jul 2128358013 km
31 Jul 2129357265 km
29 Aug 2129358111 km
17 Sep 2130356934 km
16 Oct 2130357874 km
04 Nov 2131356693 km
04 Dec 2131358111 km
22 Dec 2132356578 km
20 Jan 2133358487 km
10 Jan 2134358877 km
08 Feb 2134356416 km
28 Feb 2135358653 km
29 Mar 2135356786 km
16 Apr 2136358601 km
15 May 2136356936 km
03 Jun 2137358509 km
03 Jul 2137356978 km
22 Jul 2138358678 km
20 Aug 2138357079 km
08 Sep 2139358359 km
07 Oct 2139356743 km
25 Oct 2140357961 km
24 Nov 2140356703 km
13 Dec 2141357640 km
11 Jan 2142356818 km
30 Jan 2143357159 km
01 Mar 2143356964 km
19 Mar 2144357260 km
17 Apr 2144357504 km
06 May 2145357329 km
05 Jun 2145357625 km
24 Jun 2146357314 km
23 Jul 2146357668 km
11 Aug 2147357432 km
09 Sep 2147357733 km
27 Sep 2148357048 km
27 Oct 2148357487 km
15 Nov 2149356777 km
14 Dec 2149357737 km
02 Jan 2151356640 km
01 Feb 2151358100 km
20 Feb 2152356476 km
20 Mar 2152358490 km
08 Apr 2153356827 km
27 May 2154356933 km
14 Jul 2155356938 km
30 Aug 2156356994 km
18 Sep 2157358761 km
18 Oct 2157356624 km
06 Nov 2158358314 km
05 Dec 2158356578 km
24 Dec 2159357955 km
23 Jan 2160356682 km
10 Feb 2161357472 km
11 Mar 2161356814 km
30 Mar 2162357581 km
29 Apr 2162357310 km
18 May 2163357627 km
16 Jun 2163357376 km
04 Jul 2164357584 km
02 Aug 2164357382 km
21 Aug 2165357654 km
20 Sep 2165357413 km
09 Oct 2166357216 km
07 Nov 2166357158 km
26 Nov 2167356916 km
26 Dec 2167357418 km
13 Jan 2169356759 km
11 Feb 2169357764 km
02 Mar 2170356595 km
01 Apr 2170358119 km
20 Apr 2171356928 km
19 May 2171358646 km
06 Jun 2172356990 km
05 Jul 2172358627 km
24 Jul 2173356959 km
23 Aug 2173358651 km
11 Sep 2174356970 km
10 Oct 2174358717 km
29 Oct 2175356563 km
27 Nov 2175358680 km
16 Nov 2176358713 km
15 Dec 2176356511 km
04 Jan 2178358324 km
02 Feb 2178356601 km
21 Feb 2179357844 km
23 Mar 2179356718 km
10 Apr 2180357961 km
09 May 2180357170 km
28 May 2181357984 km
26 Jun 2181357183 km
15 Jul 2182357911 km
14 Aug 2182357155 km
02 Sep 2183357930 km
Date Distance
01 Oct 2183357152 km
19 Oct 2184357433 km
17 Nov 2184356887 km
06 Dec 2185357106 km
05 Jan 2186357153 km
24 Jan 2187356931 km
22 Feb 2187357476 km
13 Mar 2188356767 km
11 Apr 2188357793 km
30 Apr 2189357083 km
29 May 2189358257 km
17 Jun 2190357104 km
17 Jul 2190358189 km
05 Aug 2191357035 km
03 Sep 2191358190 km
21 Sep 2192356999 km
20 Oct 2192358243 km
08 Nov 2193356556 km
08 Dec 2193358221 km
27 Dec 2194356497 km
25 Jan 2195358821 km
15 Jan 2196358740 km
13 Feb 2196356572 km
04 Mar 2197358270 km
02 Apr 2197356673 km
21 Apr 2198358395 km
20 May 2198357082 km
08 Jun 2199358397 km
08 Jul 2199357046 km
27 Jul 2200358293 km
25 Aug 2200356985 km
13 Sep 2201358258 km
12 Oct 2201356949 km
31 Oct 2202357701 km
30 Nov 2202356673 km
19 Dec 2203357349 km
17 Jan 2204356943 km
04 Feb 2205357161 km
06 Mar 2205357238 km
25 Mar 2206356997 km
23 Apr 2206357516 km
12 May 2207357295 km
11 Jun 2207357922 km
29 Jun 2208357276 km
28 Jul 2208357806 km
16 Aug 2209357170 km
14 Sep 2209357789 km
03 Oct 2210357085 km
02 Nov 2210357829 km
21 Nov 2211356606 km
20 Dec 2211357818 km
07 Jan 2213356542 km
06 Feb 2213358415 km
25 Feb 2214356600 km
26 Mar 2214358847 km
16 Mar 2215358756 km
14 Apr 2215356683 km
01 Jun 2216357051 km
20 Jun 2217358867 km
19 Jul 2217356967 km
07 Aug 2218358727 km
05 Sep 2218356873 km
24 Sep 2219358634 km
24 Oct 2219356802 km
11 Nov 2220358016 km
10 Dec 2220356517 km
29 Dec 2221357644 km
28 Jan 2222356787 km
16 Feb 2223357445 km
17 Mar 2223357050 km
04 Apr 2224357283 km
04 May 2224357288 km
23 May 2225357563 km
21 Jun 2225357638 km
10 Jul 2226357503 km
08 Aug 2226357479 km
27 Aug 2227357358 km
26 Sep 2227357443 km
14 Oct 2228357220 km
12 Nov 2228357472 km
01 Dec 2229356706 km
31 Dec 2229357470 km
19 Jan 2231356640 km
17 Feb 2231358057 km
07 Mar 2232356683 km
06 Apr 2232358436 km
25 Apr 2233356747 km
24 May 2233358740 km
12 Jun 2234357075 km
30 Jul 2235356944 km
29 Aug 2235358817 km
16 Sep 2236356817 km
03 Nov 2237356711 km
22 Nov 2238358379 km
21 Dec 2238356416 km
10 Jan 2240357993 km
08 Feb 2240356686 km
26 Feb 2241357789 km
28 Mar 2241356915 km
16 Apr 2242357629 km
15 May 2242357113 km
03 Jun 2243357892 km
02 Jul 2243357411 km
20 Jul 2244357788 km
19 Aug 2244357210 km
07 Sep 2245357599 km
06 Oct 2245357157 km
25 Oct 2246357409 km
23 Nov 2246357171 km
12 Dec 2247356863 km
11 Jan 2248357178 km
29 Jan 2249356796 km
27 Feb 2249357748 km
19 Mar 2250356823 km
17 Apr 2250358071 km
06 May 2251356870 km
04 Jun 2251358322 km
22 Jun 2252357159 km
22 Jul 2252358547 km
10 Aug 2253356979 km
08 Sep 2253358321 km
27 Sep 2254356817 km
26 Oct 2254358427 km
14 Nov 2255356675 km
14 Dec 2255358640 km
02 Dec 2256358786 km
01 Jan 2257356371 km
20 Jan 2258358393 km
18 Feb 2258356638 km
09 Mar 2259358187 km
08 Apr 2259356832 km
26 Apr 2260358032 km
25 May 2260356992 km
13 Jun 2261358277 km
13 Jul 2261357240 km
01 Aug 2262358128 km
30 Aug 2262356999 km
18 Sep 2263357891 km
17 Oct 2263356927 km
04 Nov 2264357644 km
04 Dec 2264356927 km
23 Dec 2265357069 km
21 Jan 2266356938 km
09 Feb 2267357005 km
11 Mar 2267357488 km
29 Mar 2268357019 km
27 Apr 2268357754 km
16 May 2269357048 km
15 Jun 2269357955 km
04 Jul 2270357300 km
02 Aug 2270358133 km
21 Aug 2271357072 km
19 Sep 2271357882 km
07 Oct 2272356871 km
06 Nov 2272357992 km
25 Nov 2273356693 km
24 Dec 2273358205 km
12 Jan 2275356382 km
11 Feb 2275358540 km
31 Jan 2276358847 km
01 Mar 2276356645 km
20 Mar 2277358646 km
18 Apr 2277356804 km
07 May 2278358495 km
06 Jun 2278356929 km
25 Jun 2279358721 km
24 Jul 2279357129 km
11 Aug 2280358523 km
09 Sep 2280356847 km
28 Sep 2281358235 km
28 Oct 2281356757 km
16 Nov 2282357932 km
15 Dec 2282356740 km
03 Jan 2284357330 km
02 Feb 2284356752 km
20 Feb 2285357273 km
21 Mar 2285357276 km
09 Apr 2286357273 km
09 May 2286357488 km
28 May 2287357286 km
26 Jun 2287357643 km
14 Jul 2288357499 km
12 Aug 2288357775 km
31 Aug 2289357220 km
29 Sep 2289357504 km
19 Oct 2290356980 km
17 Nov 2290357616 km
06 Dec 2291356765 km
04 Jan 2292357827 km
23 Jan 2293356448 km
21 Feb 2293358154 km
12 Mar 2294356705 km
10 Apr 2294358830 km
30 Apr 2295356829 km
16 Jun 2296356920 km
03 Aug 2297357075 km
20 Sep 2298356751 km
10 Oct 2299358624 km
08 Nov 2299356641 km

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