Concept
Full moon
Related concepts (28)
Ecclesiastical full moon
An ecclesiastical full moon is formally the 14th day of the ecclesiastical lunar month (an ecclesiastical moon) in an ecclesiastical lunar calendar. The ecclesiastical lunar calendar spans the year with lunar months of 30 and 29 days which are intended to approximate the observed phases of the Moon. Since a true synodic month has a length that can vary from about 29.27 to 29.83 days, the moment of astronomical opposition tends to be roughly 14.75 days after the previous conjunction of the Sun and Moon (the new moon).
Syzygy (astronomy)
_Syzygy In astronomy, a syzygy (ˈsɪzədʒi ; ) is a roughly straight-line configuration of three or more celestial bodies in a gravitational system. When Earth is one of the bodies involved, the other objects appear to be close together (or overlapping) in the sky. The word is often used in reference to the Sun, Earth, and either the Moon or a planet, where the latter is in conjunction or opposition. Solar and lunar eclipses occur at times of syzygy, as do transits and occultations.
Supermoon
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 Moon as viewed from Earth. The technical name is a perigee syzygy (of the Earth–Moon–Sun system) or a full (or new) Moon around perigee. Because the term supermoon is astrological in origin, it has no precise astronomical definition.
Moonlight
Moonlight consists of mostly sunlight (with little earthlight) reflected from the parts of the Moon's surface where the Sun's light strikes. The ancient Greek philosopher Anaxagoras was aware that "the sun provides the moon with its brightness". The intensity of moonlight varies greatly depending on the lunar phase, but even the full moon typically provides only about 0.05–0.1 lux illumination. When a full Moon around perigee (a "supermoon") is viewed around upper culmination from the tropics, the illuminance can reach up to 0.
Moon illusion
The Moon illusion is an optical illusion which causes the Moon to appear larger near the horizon than it does higher up in the sky. It has been known since ancient times and recorded by various cultures. The explanation of this illusion is still debated. The angle that the diameter of the full Moon subtends at an observer's eye can be measured directly with a theodolite to show that it remains constant as the Moon rises or sinks in the sky. Photographs of the Moon at different elevations also show that its size remains the same.
Almanac
An almanac (also spelled almanack and almanach) is a regularly published listing of a set of current information about one or multiple subjects. It includes information like weather forecasts, farmers' planting dates, tide tables, and other tabular data often arranged according to the calendar. Celestial figures and various statistics are found in almanacs, such as the rising and setting times of the Sun and Moon, dates of eclipses, hours of high and low tides, and religious festivals.
Daylight
Daylight is the combination of all direct and indirect sunlight during the daytime. This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected by Earth and terrestrial objects, like landforms and buildings. Sunlight scattered or reflected by astronomical objects is generally not considered daylight. Therefore, daylight excludes moonlight, despite it being reflected indirect sunlight. Daylight is present at a particular location, to some degree, whenever the Sun is above the local horizon.
Lunar standstill
A lunar standstill or lunistice is when the moon reaches its furthest north or furthest south point during the course of a month (specifically a draconic month of about 27.2 days). The declination (a celestial coordinate measured as the angle from the celestial equator, analogous to latitude) at lunar standstill varies in a cycle 18.6 years long between 18.134° (north or south) and 28.725° (north or south), due to lunar precession. These extremes are called the minor and major lunar standstills.