What this table measures
The first planetary hour begins at local sunrise. The hours are unequal to a modern clock hour because the entire span from sunrise to sunset is divided into twelve. The night span from sunset to the following sunrise is also divided into twelve. When daylight exceeds twelve clock hours, each planetary day hour is longer than sixty minutes, while each night hour is shorter. The result reverses when the nights are longer.
These divisions are sometimes called temporary or seasonal hours. The planet labels follow a seven-name sequence, beginning with the weekday’s ruler at sunrise. They are a historical symbolic calendar. The calculated Sun crossings are astronomical estimates, while the ruler labels come from a human tradition. The displayed time can differ from another service if it uses a different horizon height, atmospheric assumption, coordinates, or time-zone rule.