Korean sky events · KST

Supermoons and blue moons: names and observing conditions

Learn differing definitions, the Moon illusion and two meanings of blue moon.

01

Supermoon is a size-comparison label

The elliptical orbit changes lunar distance. Full Moons near perigee are often called supermoons, but classifications vary. The label does not guarantee the brightest Moon or the best weather.

02

The horizon Moon also involves an illusion

The Moon near buildings and trees can appear much larger than the high Moon. Separate this illusion from distance-related angular size. Compare photos at the same focal length and scale.

03

Blue moon usually does not mean blue color

A common definition is the second full Moon in a calendar month; another is the third of four full Moons in a season. Time zones can change calendar dates, so foreign lists should not be copied directly into a Korean calendar.

04

Check time and skyline after the label

Use the calendar and purpose planner, then check obstructions and haze in the rise direction. Verify access before making a long trip.

Reviewed: 2026-10-13. Ephemerides cannot predict weather or local obstructions.

Sources and local charts

Purpose planner · Observing places · All sky guides

A full-Moon date is not an observing appointment

The calendar uses representative daily values. The astronomical full Moon is one calculated instant, which can fall in daylight in Korea. A near-full disk can still look round on adjacent nights. Check local rise, set and altitude before choosing a time.

  1. For an event, separate the global date, the source time standard and your local date.
  2. An eclipse is visible only while the Moon is above your horizon; a global maximum need not be visible from Korea.
  3. Recheck the observing direction, access restrictions and forecast on the day you go.

Local rise and set times · Plan Moon viewing · KASI official astronomy information

Guide updated: