field of view
- The angular size of the actual patch of sky being viewed by an instrument
(usually less than 1°).
- The apparent size of the field stop
as seen through an eyepiece (20°
to 90°, depending on the eyepiece). The actual field of
view is the angle, measured on the sky, from one edge of the
eyepiece field of view to the other; approximately equal to the apparent
field of view divided by the magnification.
The apparent field of view is the field of view that
is written on eyepieces. To get the true field of view, the apparent
field must be divided by the magnification of the telescope.
AND OPTICAL PHENOMENA