ब्राह्मस्फुटसिद्धान्त (ब्रह्मगुप्त - शून्य, कुट्टक, बीजगणित एवं सम्पूर्ण २१ अध्याय सान्वय सटीक)

GOLAYANTRA OR ARMILLARY SPHERE 341
equinoctial colure, and adding an inner secondary of the ecliptic,
which as well as the meridian, is doubled.
According to Lalande, the astrolobe of Ptolemy, from which
Tycho Brahe derived his equatorial armillary, consisted only of
four circles: two placed at right angles to represent the ecliptic
and solstitial colure; a third turning on the poles of the ecliptic
and serving to mark longitudes; and a fourth, within the other
three, furnished with sights to observe celestial objects and
measure their latitudes and longitudes.
Whether the ancient Greeks had any more complicated
instrument formed on similar principles, and applicable to astro-
nomical observations, is perhaps uncertain. We have no detailed
description of the instrument which Archimedes is said to have
devised to represent the phenomena and motions of the heavenly
bodies; nor any sufficient hint of its construction; nor does
Cicero’s account of the sphere exhibited by Posidonius suggest a
distinct notion of its structure.
Among the Arabs, no addition is at present known to have
been made to the armillary sphere; between the period when the
Almagest was translated and the time of Alhazen, who wrote a
treatise of optics, in which a more complicated instrument than
that of Ptolemy, is described; Alhazen’s armillary sphere is stated
to have been the prototype of Tycho Brahe’s; but neither the
original treatise, nor the Latin translation of it, are procurable
and one is therefore unable to ascertain whether the sphere,
mentioned by the Arabian author, resembled that described by
Indian astronomers. At all events, says Colebrooke, he is more
modern than the oldest of the Hindu writers.
Here we give the literal translation of the passage on armi-
llary sphere or Golayantra occurring in the Sūrya-Siddhānta :
Let the astronomer frame the surprising structure of
the terrestial and celestial spheres.
Having caused a wooden globe to be made (of such
size) as he pleases; to represent the Earth : with a
staff for the axis passing through the centre, and
exceeding the globe at both ends; let him place the
supporting hooks, as also the equinoctial circle.
Three circles must be prepared, (divided for signs and
degrees), the radius of which must agree with the