Names of Lunar Phases
The phases of the Moon have been given the following names, in sequential order:
| Phase | Northern Hemisphere | Southern Hemisphere | Visibility | Standard time of culmination (mid-phase) |
|---|---|---|---|---|
| New moon | Not visible, traditionally Moon's first visible crescent | after sunset | 12 noon | |
| Waxing crescent moon | Right 1–49% visible | Left 1–49% visible | afternoon and post-dusk | 3 pm |
| First quarter moon | Right 50% visible | Left 50% visible | afternoon and early night | 6 pm |
| Waxing gibbous moon | Right 51–99% visible | Left 51–99% visible | late afternoon and most of night | 9 pm |
| Full moon | Fully visible | Fully visible | sunset to sunrise (all night) | 12 midnight |
| Waning gibbous moon | Left 51–99% visible | Right 51–99% visible | most of night and early morning | 3 am |
| Third (last) quarter moon | Left 50% visible | Right 50% visible | late night and morning | 6 am |
| Waning crescent moon | Left 1–49% visible | Right 1–49% visible | pre-dawn and morning | 9 am |
| Dark moon | Not visible, traditionally Moon's last visible crescent | before sunrise | 12 noon | |
When the Sun and Moon are aligned on the same side of the Earth the Moon is "new", and the side of the Moon visible from Earth is not illuminated by the Sun. As the Moon waxes (the amount of illuminated surface as seen from Earth is increasing), the lunar phases progress from new moon, crescent moon, first-quarter moon, gibbous moon and full moon phases, before returning through the gibbous moon, third-quarter (or last quarter) moon, crescent moon and new moon phases. The terms old moon and new moon are interchangeable, although new moon is more common. Half moon is often used to mean the first- and third-quarter moons, while the term 'quarter' refers to the extent of the moon's cycle around the Earth, not its shape.
When a sphere is illuminated on one hemisphere and viewed from a different angle, the portion of the illuminated area that is visible will have a two-dimensional shape defined by the intersection of an ellipse and circle (where the major axis of the ellipse coincides with a diameter of the circle). If the half-ellipse is convex with respect to the half-circle, then the shape will be gibbous (bulging outwards), whereas if the half-ellipse is concave with respect to the half-circle, then the shape will be a crescent. When a crescent Moon occurs, the phenomenon of Earthshine may be apparent, where the night side of the Moon faintly reflects light from the Earth.
In the northern hemisphere, if the left side of the Moon is dark then the light part is growing, and the Moon is referred to as waxing (moving toward a full moon). If the right side of the Moon is dark then the light part is shrinking, and the Moon is referred to as waning (moving toward a new moon). Assuming that the viewer is in the northern hemisphere, the right portion of the Moon is the part that is always growing (i.e., if the right side is dark, the Moon is growing darker; if the right side is lit, the Moon is growing lighter). In the southern hemisphere the Moon is observed from a perspective inverted to that of the northern hemisphere, so the opposite sides appear to grow (wax) and shrink (wane).
Read more about this topic: Lunar Phase
Famous quotes containing the words names of, names, lunar and/or phases:
“If goodness were only a theory, it were a pity it should be lost to the world. There are a number of things, the idea of which is a clear gain to the mind. Let people, for instance, rail at friendship, genius, freedom, as long as they will—the very names of these despised qualities are better than anything else that could be substituted for them, and embalm even the most envenomed satire against them.”
—William Hazlitt (1778–1830)
“Consider the islands bearing the names of all the saints, bristling with forts like chestnut-burs, or Echinidæ, yet the police will not let a couple of Irishmen have a private sparring- match on one of them, as it is a government monopoly; all the great seaports are in a boxing attitude, and you must sail prudently between two tiers of stony knuckles before you come to feel the warmth of their breasts.”
—Henry David Thoreau (1817–1862)
“A bird half wakened in the lunar noon
Sang halfway through its little inborn tune.”
—Robert Frost (1874–1963)
“That man is to be pitied who cannot enjoy social intercourse without eating and drinking. The lowest orders, it is true, cannot imagine a cheerful assembly without the attractions of the table, and this reflection alone should induce all who aim at intellectual culture to endeavor to avoid placing the choicest phases of social life on such a basis.”
—Mrs. H. O. Ward (1824–1899)