Phosphorus (morning star) Phosphorus (morning star) Phosphorus (Greek "Phōsphoros") is the Morning Star, the planet Venus in its morning appearance. Φαοσφόρος ("Phaosphoros") and Φαεσφόρος ("Phaesphoros") are forms of the same name in some Greek dialects. This celestial object was named when stars and planets were not always distinguished with modern precision. Another Greek name for the Morning Star is Heosphoros (Greek "Heōsphoros"), meaning "Dawn-Bringer". The form Eosphorus is sometimes met in English, as if from Ἠωσφόρος ("Ēōsphoros"), which is not actually found in Greek literature, but would be the form that Ἑωσφόρος would have in some dialects. As an adjective, the Greek word
Sunrise is 34 arcminutes, though this amount varies based on atmospheric conditions. Also, unlike most other solar measurements, sunrise occurs when the Sun's "upper limb", rather than its center, appears to cross the horizon. The apparent radius of the Sun at the horizon is 16 arcminutes. These two angles combine to define sunrise to occur when the Sun's center is 50 arcminutes below the horizon, or 90.83° from the zenith. The timing of sunrise varies throughout the year and is also affected by the viewer's longitude and latitude, altitude, and time zone. These changes are driven by the axial tilt of