Eyepiece and telescope pairing

Tele Vue 32mm Plossl in the Celestron NexStar 4SE: magnification and field

What the Tele Vue 32mm Plossl does in the Celestron NexStar 4SE, worked from the published focal lengths and apparent field.

Field of view

ring = 1.21 degrees true
dot = 2.5 mm exit pupil

Computed optics

Magnification
41x1325 mm / 32 mm
True field
1.21 degrees50 deg / 41x
Exit pupil
2.5 mm102 mm / 41x
Max useful mag
241xpublished
Barrel match
1.25 in eyepiece in a 1.25 in focuser
Fits

Good fit. In the Celestron NexStar 4SE the Tele Vue 32mm Plossl gives 41x with a 1.21 degree true field and a 2.5 mm exit pupil, inside the telescope's useful range.


Magnification is the telescope focal length divided by the eyepiece focal length: 1325 mm divided by 32 mm is 41x. The true field of view is the eyepiece's 50 degree apparent field divided by that magnification, 1.21 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 102 mm over 41x, which is 2.5 mm. That makes this a medium-power general setting.