PLANISPHERIC ASTROLABE; North India; diameter: 360 mm, weigh - Lot 448

PLANISPHERIC ASTROLABE; North India; diameter: 360 mm, weight: 4.580 kg; silver; Ngari (Sanskrit) script. Spider for 29 stars, 20 of which are named, with almost complete equatorial circle. This astrolabe consists of a single tympanum for latitude 27°. The limb is divided by 1/2 degrees and numbered in groups of 6°. On the front of the throne is the engraved word "'Sakti" i.e. power. On the back, degree scales, sine/cosine graph, shadow square (0-12-0 and 0-7-0), astrological chart and zodiac sign arcs with 9 hourly scales inscribed in ghâti . The alidade pinnae are fitted with a sighting tube and small sighting holes. Silver astrolabes are virtually unknown, although they are referred to in Islamic literature such as The Thousand and One Nights; this instrument was probably commissioned by a royal client. However, its interest lies not only in the value of the metal from which it is made, but also in the unusual presence of a ghâti scale that enabled the instrument to be used as a sundial, with the aid of the alidade (cf. unequal hours diagram on European astrolabes).