Literally out of this world, the classic-cased timepieces by Dutch watchmaker Christian van der Klauuw are astronomically complicated. Measuring everything from the position of the planets, the constellations, worldwide sunrises, sunsets, solar and lunar eclipses, each model is handmade by Christiaan himself resulting in a very limited edition of each. Originally an astronomical clockmaker, the watches were developed after he miniaturized highly complicated movements of his own design.
Self-lauded as the smallest planetarium in the world, the obviously named "Planetarium" (pictured above left) features a heliocentric revolution of the planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn) and is available from Watch Buys for $23,700. It's best experienced by watching the animation here.
Introduced at the 2006 Basel World, his most recent invention, the "Venus" (pictured above center) features a very animated dial with separately rotating Earth, Moon and Venus orbiting the Sun amidst the Constellations. It sells from Watch Buys for $19,800 and the animation is here.
Frighteningly complex, the "Astrolibium" (pictured above left) measures celestial bodies and constellations. I won't even try to regurgitate the mind numbing details here, see the animation here and info here for yourself.
A variation of the Astrolibium, the "Mondial CK1" is customized according to your location on the globe, featuring a sunrise/sunset gauge for the rest of the planet. It's far better (and more expensive at $16,200 from Watch Buys) than your simple-minded moonphase. See the animation here.
For images of one of Christiaan van der Klaauw's original Astronomical Clocks and more images of the watches they inspired, go here.