Planetarium with Astrolabium

The planetarium is situated outside the circle of the astrolabe with a scale of 0 – 360 degrees. The planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, are visible behind the dial. The 12 zodiac signs are displayed on the dial. Where each planet in which constellation stands is easy to read. The sun is positioned in the centre of the dial. In this astronomical clock the planets turn counter clockwise in sidereal time (see the table below for specifications).

In the orbits of the planets the ascending and descending nodes are displayed for each specific planet. The zodiac signs are displayed on the dial as they stood on the firmament approximately 3000 years ago. Also taken in account is the precession of the Earth with the current positions of the zodiac signs. On the firmament the current zodiac signs have shifted by one zodiac sign due to the precession of the Earth.

The astrolabe is situated the circle with the 0 – 360 degree scale. The astrolabe is provided with a sundial with a 0-24 hours scale, moon hand with phase, dragon hand and zodiac signs with star dial. Engraved in the dial are the tropic of Cancer (+23,5 degrees), equator (0 degrees), the tropic of Capricorn (-23,5 degrees), 12 arches of unequal hours, 1 – 24 hours scale, the aforementioned 0 – 360 degrees azimuth scale and in red the horizon. All circles and lines on the dial are constructed through the stereographic projection of the latitudes and longitudes we know from a virtual world globe.


Average orbit time
Niek Swelsen
Astronomical Clocks
Orbit in days