There are many sundials that can be used to determine the time at your own location. But what does it look like when the sun has long since set? This is where the far less well-known sundial comes into play. They can also be used to determine the local time (i.e. solar time) at night. In the northern hemisphere, this has been done for centuries with the help of Polaris - one of the brightest stars in the northern hemisphere - and the star Kochab, which can be found in the same constellation (Ursa minor).

The special feature of our solid brass and steel star clock is that its back allows you to tell the time at night even when you are in the southern hemisphere. Until now, the function of such a star clock was limited to the northern hemisphere, but since 2023, thanks to Australian scientist Tony Sprent, the constellations of the southern sky at night can also be used to determine the local time: To do this, take aim at the Southern Cross and the stars Alpha and Beta Centauri in the constellation Centaurus.

Incidentally, the exact date of the invention of the Nocturlabium star clock is not known; the oldest known written reference to such a device dates back to 1295. Our Nocturnal star clock follows a historical model from 1570; it can be found in the British Museum in London.

Please note that the star clock must be converted to the current local time. To do this, the equation of time must be applied, summer time corrected if necessary and longitude adjusted. The enclosed instructions briefly explain how this is done and, of course, also help you to find and aim at the required pointer stars in the firmament with the help of clear little illustrations.