Star clock - nocturne and mechanical tide computer, abacus H31 Max. height 12 cm; Wed 9.5 cm, d. 0,7 cm (14mm) weight 400gr Reproduction of a star clock (night clock) and a mechanical tide computer. The instrument is from 1570, built by Humphrey Cole. Original kept at the British Museum. Made of zamak and brass, varnished using the technique from centuries ago. Nocturne - the star clock is a beautiful instrument that allows you to determine the time at night by the position of the stars. The device consists of a fixed disc divided into months, with all days of the year marked, a movable disc with the determination of hours on a scale of 1-12 topped with an indicator - the face of the moon and a long arm of a movable indicator. In the center of the device, there is a sight through which we target the North Star - a fixed point around which other constellations, such as the Big Dipper, orbit. And it is precisely because the position of the North Star is fixed that we can relate to it the positions of other constellations that change over time. Our device - a replica of the device from 1570. is dedicated to the Kochab star in the constellation Little Dipper. But most often and probably the easiest way is to set the indicator arm on the rear axle of the Big Dipper and the movable dial on the current date. This allows you to read the current sidereal time. The device is universal - it works at all longitudes of the Northern Hemisphere. Please remember that the sidereal time does not have to coincide with the official time. Great fun! On the other side of the device is a mechanical tide computer - the abacus, a device that allows you to predict when the tides will appear. The instrument consists of a fixed dial marked with degrees from 0 to 360, an hour scale and a wind rose. There are 2 movable discs mounted on it. One - specifying the lunar month with a scale of 1-30 and the other with the pointer showing the shape of the moon, which changes as the pointer moves. The device takes into account the direction of the wind, the number of days since the new moon, the current age of the moon, which allows you to predict sea tides. A great gift for a sailor, fisherman, astronomer or enthusiast of technical monuments. User manual in English, French, Italian and Spanish. A product of the Spanish company Hemisferium. The set includes an attractive decorative box with an insert on which the device rests.