Planetary Hours Clock Screensaver
The Planetary Hours Clock screensaver shows which classical planet really rules the current hour. It is free, runs in your browser, and ESC exits.
How the Planetary Hours Clock screensaver works
The saver computes your city's real sunrise and sunset for today and tomorrow.
Daytime and nighttime are each split into 12 real planetary hours.
Hours cycle through the seven classical planets in their traditional order.
Everything is computed locally — no network, no key.
A worked example
Each real planetary hour's length changes with the season, since it is one-twelfth of the real day or night, not a fixed 60 minutes.
Settings & tips
- Planetary hours are unequal — their length tracks real day length.
- Location switches the real sunrise/sunset city used.
- The ruling order repeats: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon.
Frequently asked questions
- Are planetary hours equal to 60 minutes?
- No — each is one-twelfth of the real local day or night, so length varies by season.
- How is sunrise/sunset computed?
- From a real local solar-altitude calculation for your chosen city, the same method as the Daylight Clock saver.
- Is a key needed?
- No. Everything is computed locally in your browser.
- Is it free?
- Yes — free, no download, in your browser.