On this page: each half of the wave is divided into 12 equal parts, the “daylight hour” and “night hour” in the tables, like the historical unequal hours. Solar noon and midnight follow apparent solar time, not the clock. Clock times are shown in this device’s time zone. The page is white while slnočas is positive and black while it is negative. Until you pick a place, your approximate location is guessed from your IP address (via geojs.io); place search uses Open-Meteo. Your chosen place is remembered only in this browser.
Slnočas
Slnočas is local: it needs a place to be calculated for.
Length of a daylight hour (solid) and night hour (dashed) in minutes · tap or drag to pick a day
About slnočas
Inspired by sundials and Japanese timekeeping, I started to wonder whether I could create a timekeeping method of my own. I started from two premises. First, I believe there is something inherently crucial about the Sun, sunrise and sunset. Second, I perceive the time of day as a wave that follows the sunlight—noon is the “peak” of the day, not its half. So I devised a simple scale called slnočas (“suntime” in Slovak).
Slnočas starts at sunrise, where it reads 0. Over the course of the day it rises smoothly towards 1, which it reaches at solar noon, the peak of the day, and then falls back to 0 at sunset. After sunset it continues to “fall”, reaching −1 at solar midnight, and then climbs back to 0 at the next sunrise. The wave is not a measurement of how high the Sun actually stands; it is stretched to fit the day. The daylight half always spans the whole time from sunrise to sunset, however long that is, and the night half fills the rest. In Bratislava in June the climb from 0 to 1 takes about eight hours and the fall from 0 to −1 about four; in December it is the other way round. Slnočas therefore runs fast in winter days and slow in summer ones. Same as 和時計 (wadokei), it reflects the sun, just in a more modern numeric format. Needless to say, slnočas doesn’t do daylight saving time.
This also means that slnočas is extremely local and needs to be calculated for specific coordinates. The other option is using a specifically crafted sundial, also made for specific coordinates—as all common sundials are.