Approximately,
o
e
L
D
m
f
f
=
×
where fo and fe are the focal lengths of the objective and eyepiece,
respectively, and L is the distance between their focal points 9 Magnifying power m of a telescope is the ratio of the angle b subtended
at the eye by the image to the angle a subtended at the eye by the
object o
e
f
m
f
=αβ
=
where f0 and fe are the focal lengths of the objective and eyepiece,
respectively