Correlating the celestial and terrestrial spheres | Declination and latitude | zero shadow days скачать в хорошем качестве

Correlating the celestial and terrestrial spheres | Declination and latitude | zero shadow days

By definition, the celestial sphere models the entirety of space around the terrestrial sphere. Hence, it should be possible to correlate places on the terrestrial sphere to celestial coordinates. The primary correlation is between the declination of the equatorial coordinate system and the latitude of the geographic coordinate system. More specifically, when the Sun reaches a particular declination (say +10°), then it will be directly overhead any place situated on 10° latitude on the Earth, at local noon. The time of local noon will vary across places depending on their geographic longitude. When the Sun comes directly overhead a place, it will not possible to observe any shadows on the ground. Hence, a day when the Sun comes directly overhead a place is called a "zero shadow day" for that place. Every year, there will be two zero shadow days for any given place - one during uttarayana and another during dakshinayana. This tutorial illustrates all these concepts using major Indian cities such as Bangalore, Hyderabad, Mumbai and Kolkata.