सिद्धान्तदर्पण (महामहोपाध्याय सामन्त चन्द्रशेखर सिंह - नग्न-नेत्र खगोल वेध एवं गणित महाकोश)

Introduction lxvii
the long ascendancy of the Almagest was fast
coming to a close. Chandrasekhara's Almagest was
Surya-Siddhanta, and his Copernicus was Bhaskara.
Both Tycho and Chandrasekhara detected at an
early age discrepancies between observation and
calculation. Tycho held and Chandrasekhara still
holds the same views about the solar system. The
Copernican theory was before Tycho, and
Chandrasekhara knew the theory of Aryabhatta,
and we may add, heard not only of the diurnal
rotation of the earth propounded by the renowned
Aryabhatta, but of the annual revolution of the
earth round the Sun from modern Geography. But
both declined to accept the new theory on almost
precisely the same grounds. Tycho rejected the
Copernican theory chiefly for two reasons. "One
reason," says Professor Young, was that it was
unfavourably regarded by the clergy, and he was a
good churchman. The other was the scientific
objection that if the earth moved round the Sun,
the fixed stars all ought to appear to move in a
corresponding manner each star describing annually
an oval in the heavens of the same apparent
dimensions as the earth's orbit itself, seen from the
star. Technically speaking, they ought to have an
annual parallax."¹ Chandrasekhara is equally

1. The fact that the stars should have parallaxes if the earth
   revoired around the Sun was known at a very early date.
   Tycho Brahe observed them in order to discover whether
   they were sensibly fixed in the sky or not. So far his
   observations went they did not change their positions
   during the year. He inferred from this that the earth
   remained fixed and that the Sun moved. His error was
   due to the fact that his observatons were not sufficiently
   accurate to show the slight displacement which the stars