Astronomy Blog

Astronomical Clock

Whilst visiting the Italian town of Brescia in July 2006, I noticed an 16th century astronomical clock in the marketplace. It was really quite interesting, not just because of the astronomy connections, but also because it appears to be a true 24 hour clock rather than the familiar 12 hour clocks we usually see. The clock itself is situated on the Torre dell'Orologio (I think that literally translates as Tower of Time) in the Piazza della Loggia and I took a picture of it.

I don't have much knowledge of astronomical clocks so I've been trying to work out what sort of information it includes. I have already said that I think this is a true 24 hour clock. My reasoning stems from the 24 Roman numerals around the outer circle. This is backed up by the position of the moveable Sun symbol and the time of day I took the image give or take potential differences between my camera clock and this clock's knowledge of time zones and daylight savings. The next ring in (ignoring the thin gold decoration ring) appears to show the 12 constellations of the Zodiac. I didn't hang around long enough to find out whether that ring rotated once every astronomical day or not.

The next three narrow rings appear to indicate the date (which was the 30th July) using Roman month names and numerals although I'm not entirely sure what the numbers 0 to 12 to 0 are supposed to represent. The inner circle shows the phase of the Moon and the little Moon symbol may be supposed to show the time of new Moon. However, new Moon was on the 25th July in 2006 rather than the 27th so my assumptions may be incorrect or the clock may need a little recalibrating.

The clock was a fascinating piece of history and I apparently missed the other astronomically interesting sites nearby.