Horologium – the clock

May 28, 2017

The constellation Horologium represents a clock and usually is portrayed as one of the old-timey types. Nicolas Louis de Lacaille created it and drew it as a grandfather hall clock with a pendulum and weights.

Lacaille added 14 constellations to the map in an effort to flesh out the southern sky. In general he used them to commemorate important inventions that help usher in the age of enlightenment. Reliable clocks were significant in that regard so it seems only fair that the device be included.

If you view the stars of this area it’s possible that Alpha Horologii is the only star you’ll see and it’s not terribly bright. It’s an orange giant and in allegorical drawings it usually winds up being the brass bob at the end of the clock’s pendulum.

There is a globular cluster in this direction called Arp-Madore 1. It is currently the most distant globular cluster known to orbit our Milky Way galaxy. It’s almost 400,000 light years away. Considering that the bright disk of our galaxy is a mere 100,000 light years across, that gives you some scale of the big halo of crap orbiting around us. Imagine living on a planet in Arp-Madore 1 and looking up at night and seeing the full glory of the Milky Way. Except in a globular cluster most planets probably don’t have anything resembling “night.”

The Horologium Supercluster is off in the direction of Horologium appropriately, and it is one of the biggest architectural features in the universe. It is composed of more than 5,000 clusters of galaxies. That’s more than 300,000 galaxies, and each galaxy has billions, hundreds of billions, or trillions of stars. Our own galaxy is not one of them however. The Horologium Supercluster is our local supercluster’s next door neighbor. Be sure to wave. Our own galaxy’s address is part of the Laniakea Supercluster, which contains the Virgo Supercluster, which use to be thought of as our whole entire local supercluster but is now thought to be only a subdivision of the Laniakea Supercluster.