Basic

2. Definition
 The celestial sphere is
an imaginary sphere in the
sky. It is the base of
positional astronomy.
 The position of
planets, stars etc are based
on this sphere.
 Co ordinates in the sky
called right ascension and
declination gives position
of stellar objects.

7.  Horizontal system
 Equatorial System
 Ecliptic System
 Meridian System
There are four co ordinate
system

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