The author reflects on the changing length of days in relation to the vernal equinox, prompted by observing a colleague’s window gradually brighten in Stavanger, Norway. An interactive graph is created to show how the length of the day evolves with latitude and from day to day, revealing interesting patterns including ‘zigzag’ day lengths near the Arctic Circle. Mathematical calculations involving the observer’s latitude, Sun’s declination, and solar hour angle are elaborated upon, shedding light on the intricacies of daylight variations. Complications such as atmospheric refraction, solar limb width, and Earth’s elliptical orbit are discussed to provide a deeper understanding of daylight duration.
https://joe-antognini.github.io/astronomy/daylight