This visualization represents the visibility of the Sun (evening and morning twilights, night hours), Moon (rising and setting times; also its phase) and the planets (rising, culmination and setting times) during a given year and a given location on Earth. It is inspired on the spanish "Guía del cielo" annuary and the Sky&Telescope diagrams. 

The horizontal axis is the hour of the day (centered on midnight) while the vertical axis is the date within the year. Best visibility of the planets throughout the year can easily be spotted (e.g, Venus after dawn during June or before dusk during December), nighttime intervals without Moon (for deep sky observation), changing twilight times during the year, etc.

It is implemented as a python script that computes all the celestial body positions for the given location and date range and then plots the visibility data using matplotlib.