The Astronomical Observatories of Jai Singh c5.7

c5.7

Two pages of the Jaipur manuscripts are shown in Plate I (Figures 1, 2), and I give below extracts⁴ from the manuscripts together with a table of comparisons. The manuscript gives: (*a*) The numbers of the constellations and star numbers, and these in all cases follow Ulugh Beg's order exactly. (*b*) The nomenclature, which is a translation from Ptolemy (through Ulugh Beg). In a few cases the Persian and Hindu names are also given. (*c*) Ulugh Beg's longitudes with 4°8' added for precession. (*d*) The latitude which in practically all cases is the same as Ulugh Beg's. (*e*) The so-called polar longitudes⁵ (what Delambre calls ‘false longitudes’); this is the *Sūrya Siddhānta* method of indicating the positions of stars, but it also occurs in Muslim works, e.g., Abū ‘Alī al-Ḥasan in the 13th century of our era calculates the polar longitudes for a number of stars; and the presence of these polar longitudes in Jai Singh's catalogue is possibly due to Muslim and not Hindu influence. (*f*) Declinations, and (*g*) Right ascensions apparently read off from a globe. (*h*) Right ascension in *ghaṭis* and *palas* obtained from (*g*) by dividing by six.⁶ (*h*) Star magnitudes which seldom differ from those recorded by Ulugh Beg.