A display of historical Chinese astronomical instruments on the roof of the Beijing Ancient Observatory in Beijing, China, an astronomical observatory that dates from the 1400s. From left to right: equatorial armilla (1673) to measure true solar time and right ascension and declination of celestial objects; sextant (1673) to measure angular distance between any two stars less than 60 degrees apart, as well as angular diameters of the sun and moon; azimuth theodolite (1715) to determine azimuth and altitude (elevation angle) of celestial objects; ecliptic armilla (1673) to measure ecliptic longitude difference and latitude of celestial objects. | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Williamson, Mark |
Taille de l’image : | 5128 px × 3408 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |