- Lunar phase (Wikipedia)
A lunar phase or Moon phase is the apparent shape of the Moon’s directly sunlit portion as viewed from the Earth (because the Moon is tidally locked with the Earth, the same hemisphere is always facing the Earth). In common usage, the four major phases are the new moon, the first quarter, the full moon and the last quarter; the four minor phases are waxing crescent, waxing gibbous, waning gibbous, and waning crescent. A lunar month is the time between successive recurrences of the same phase: due to the eccentricity of the Moon’s orbit, this duration is not perfectly constant but averages about 29.5 days.
- Rigil Kentaurus (stars.astro.illinois.edu)
RIGIL KENTAURUS (Alpha Centauri) with PROXIMA CENTAURI (Alpha Cen C). Among the most famed stars of the entire sky, surely rival in renown to Sirius and Polaris even though not visible to much of the world’s population, is the “foot of the Centaur,” Rigil Kentaurus, “Rigil Kent,” the first star of Centaurus, probably much better known as Alpha Centauri or just Alpha Cen.
- Alpha Centauri (Wikipedia)
Alpha Centauri (α Centauri, Alpha Cen, or α Cen) is a triple star system in the southern constellation of Centaurus. It consists of three stars: Rigil Kentaurus (Alpha Centauri A), Toliman (B) and Proxima Centauri (C). Proxima Centauri is the closest star to the Sun at 4.2465 light-years (1.3020 pc).