How to use it
- Type the name of a city and choose it from the list. Istanbul is the starting place.
- Choose the date. The day runs from its sunrise to the next sunrise.
- Read the table: each row is one hour, with its planet and its start and end times. The current hour is marked when the date is today.
- Tick Show times in UTC if you want Universal Time.
How the hours are divided
The sunrise and the sunset are computed by astronomy-engine (MIT) for the city you choose: the moment the upper edge of the Sun reaches the horizon, with the standard allowance for refraction in the air. That is the definition the US Naval Observatory uses.
The daytime from sunrise to sunset is divided into twelve equal hours, and the night from sunset to the next sunrise into twelve more. So a daytime hour in winter is shorter than a night hour, and the lengths change every day.
day hour = (sunset − sunrise) ÷ 12
night hour = (next sunrise − sunset) ÷ 12The planets and their order
The first hour of each day belongs to the planet of that weekday: the Sun on Sunday, the Moon on Monday, Mars on Tuesday, Mercury on Wednesday, Jupiter on Thursday, Venus on Friday and Saturn on Saturday. The following hours go through the planets in the Chaldean order: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon.
The Chaldean order is the traditional sequence, from the slowest-moving planet seen in the night sky to the fastest. Its origin is a Hellenistic tradition, not an astronomical rule.
What this page does not show
- The astrological meanings of each hour. Those belong to the tradition, and the page gives the hours and their planets only.
- Places near the poles, where the Sun may not rise or set for weeks. The page says so instead of drawing hours.
Worked example: Istanbul on Tuesday 10 November 2026
The day is ruled by Mars, because 10 November 2026 is a Tuesday. In Istanbul the Sun rises at 07:45 local time (UTC+3, that is 04:45 UT) and sets at 17:50 (14:50 UT).
The first hour, from 07:45 to 08:35, is Mars. The second, from 08:35 to 09:26, is the Sun, and the third and fourth are Venus and Mercury. The thirteenth hour, the first of the night, is Saturn, from 17:50 to 18:59, after the sunset.
Frequently asked questions
Why are the hours of one day not all the same length?
Because the daytime and the night are each divided into twelve equal parts. In winter the day is shorter, so its hours are shorter than the night hours, and the lengths change every day.
Which time does the planetary day start at?
The day starts at sunrise, not at midnight, and runs to the next sunrise. Some older texts start the day at sunset, so the first hour can differ by tradition.
Why does the page need a city?
The sunrise and sunset depend on the place: its latitude and longitude, and the time zone. The same date gives different hours in different cities.
Is the sunrise shown the same as the one in the newspaper?
It is the same definition, the Sun's upper edge at the horizon with standard refraction. Small differences of a minute can come from the rounding of published tables.
Sources
- US Naval Observatory: sunrise and sunset definitions, the standard used for the times on this page
- Wikipedia: Planetary hours, the traditional division of the day and the Chaldean order
- GeoNames, the city data used for the place search (CC BY 4.0)
- astronomy-engine, the open-source astronomy library (MIT) that computes sunrise and sunset
Figures and text last checked on Tuesday, November 10, 2026.