Ecliptic
inclined at 23.5° to
celestial equator
Crosses celestial equator twice a year
Vernal Equinox
=
Ref point for RA
0
h
0
m
0
s
(Position of Sun on 1st day of spring - Mar 21)
e.g. Betelgeuse
RA 05
h
52
m
dec 7° 24’
x
