In a single hemisphere, under perfect conditions, the unaided human eye can see some 4,000 stars of the approximately 300 billion in our galaxy. These incalculably large celestial bodies, alongside the seven visible ‘Planets’, which were listed in antiquity as the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn, have been a source of endless fascination for human beings ever since the dawn of time. Every ancient culture for which we have evidence, without exception, had a rich mythos associated with stars and planets, in a vain attempt to explain these most dazzling of night-time companions. But they are not merely beautiful. From the time of the Mesopotamians, we have known that astronomy was essential to the development of accurate calendars, to calculating one’s relative and absolute position on the Earth’s surface, and even, in the case of the Greek astronomer Eratosthenes, to calculate the circumference of the Earth to within 80 km (50 miles) of the actual figure. The usefulness of the stars encouraged a bewildering array of astronomical instruments designed to map them and to calculate their positions and angles. Among the simplest of these devices was the celestial globe, an attempt at producing a map of absolute star positions.

Various Indian peoples were among the earliest to create astronomical instruments. The invention by Hindu mathematicians of the number zero, sunya, enabled whole new avenues of calculation which permitted astronomers to make ever more accurate and ever more effective predictions about the motion of stars across the sky, and about the relative position of the celestial bodies. The Hindu astronomical instruments were heavily influenced from the Seventeenth Century AD by the precision engineering of the Arab world, especially Persia. The Mughal Emperors, who conquered much of North India from the Sixteenth Century AD, brought with them Persian expertise both in the person of scientists and philosophers at the imperial court, and in the form of books, manuscripts and exemplar instruments brought from Isfahan and Tehran. The result was a rich and vibrant dynamic of academic and scientific exchange, which brought together the millennia-old traditions of the Hindu world with the cutting-edge technology brought from Islamic scholarship.

This remarkable celestial globe is far more extraordinary than it might first seem. At the basis are the elements of star-maps seen from other cultures and periods. Small silver inlays mark the positions of important asterisms, among which will be the twenty-eight nakshatra, constellations of Hindu astrology associated with major stars on the ecliptic plains. Each of these can be thought of as a ‘lunar mansion’ or ‘lunar station’, in other words, a segment of the ecliptic through which the Moon passes in its orbit around the Earth. Around the centre of the globe is a belt consisting of Devangari numerals, derived from a script commonly found in Northern Indian languages. The Devangari used in this globe is more akin to the so-called Bombay Variant than the standard or Calcutta Variant. Named for the old designation for Mumbai, this would indicate that the globe originated in the northwest of the country, close to the influences coming from the Islamic World. The globe is divided into four segments; rather than depicting various constellations spread over its surface as in many Islamic and Indo-Persian examples.

Each of these four segments depicts a different mathematical or scientific diagram, which explains something of astronomy. Perhaps the clearest of these is an image of the Sun – presented as a radiating sphere with a face – which is at the centre of an elliptical orbit, around which moves the planet Earth, At either side, facing the sun, two Janus-like faces, representing two different sides of the Earth, are presented in full view of the Sun. This reflects one of the great innovations of European astronomy, transmitted through the Arab world, originating with Nocolaus Copernicus, of a heliocentric solar system. This contradicted traditional Hindu thought which had, since the Sūrya Siddhānta in the Fifth Century AD, exclusively conceived of an Earth-centric universe. Copernicus’ ideas were more readily accepted in the Islamic World, where numerous scholars including Al-Sijzi had challenged the notion that the Earth was stationary. On two of the stations around the Sun, it demonstrates which parts of the Earth would be in shadow, and which parts would be in sunlight. Another of the segments shows five bodies in orbit around another, larger body. This may well be five of the seven moons of Saturn, known at the time, and now recognised as Iapetus, Titan, Rhea, Dione and Tethys.