L'Equazione del Tempo
  The equation of time is fundamental for calculating the rising and setting times of the Sun. The concepts of sidereal and solar day and locak noon, we show how the length of the day depends on solar declination and Earth's orbit position, and also their influence on the local noon shift. In particular we show why in the month of July the setting time is rather constant, while the daylight reduces constantly. 
Costantino Sigismondi
astro-ph.IM astro-ph.SR