A supermoon is a full moon or a new moon that nearly coincides with perigee (the closest that the Moon comes to the Earth in its elliptic orbit) resulting in a slightly larger-than-usual apparent size of the lunar disk as viewed from Earth. The astronomy term is a perigee syzygy (of the Earth–Moon–Sun system) or a full (or new) Moon around perigee.
Criteria of Supermoon
There are no official definition for a supermoon, as the term was mainly a related interest to astrology. Few criteria as follow:
- Richard Nolle (2011) defines Supermoon as any lunation closer than 368,630 km.
- Fred Espenak (2012) defines the Moon’s mean apogee and perigee distances results in a mean limiting distance of 367,607 km for a super moon.
- Fergus Wood (1976) used the definition of a full or new moon occurring within 24 hours of perigee and also used the label perigee-syzygy.
- Sky and Telescope magazine chose a definition of 223,000 miles (358,884 km)
- TimeandDate.com prefers a definition of 360,000 km (223,694 mi).
You can find the full list of Supermoon / Perigee syzygy / Full Moon around perigee for year 2020 until 2030 below compiled and computed by Hazarry Hj Ali Ahmad, the Astronomical Society of Brunei Darussalam, based on the above definitions. A logical check is also generated for the top 3 closest moon distance in that year. A personal opinion is to categories the Supermoon when at least 3 of the criterial searches were met.