A Celestron Omni 56mm Plossl in the Celestron NexStar Evolution 9.25 gives 42x, a 1.12 degree true field and a 5.6 mm exit pupil. The worked calculation and whether it sits in the useful range.

Updated 05 September 2026.

Eyepiece and telescope pairing

Celestron Omni 56mm Plossl in the Celestron NexStar Evolution 9.25: magnification and field

What the Celestron Omni 56mm Plossl does in the Celestron NexStar Evolution 9.25, worked from the published focal lengths and apparent field.

Field of view

ring = 1.12 degrees true
dot = 5.6 mm exit pupil

Computed optics

Magnification
42x2350 mm / 56 mm
True field
1.12 degrees47 deg / 42x
Exit pupil
5.6 mm235 mm / 42x
Max useful mag
555xpublished
Barrel match
2 in eyepiece in a 2 in focuser
Fits

Good fit. In the Celestron NexStar Evolution 9.25 the Celestron Omni 56mm Plossl gives 42x with a 1.12 degree true field and a 5.6 mm exit pupil, inside the telescope's useful range.


Magnification is the telescope focal length divided by the eyepiece focal length: 2350 mm divided by 56 mm is 42x. The true field of view is the eyepiece's 47 degree apparent field divided by that magnification, 1.12 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 235 mm over 42x, which is 5.6 mm. That makes this a low-power, wide-field and deep-sky setting.

Questions and answers

Celestron Omni 56mm Plossl in the Celestron NexStar Evolution 9.25: magnification and field?

Good fit. In the Celestron NexStar Evolution 9.25 the Celestron Omni 56mm Plossl gives 42x with a 1.12 degree true field and a 5.6 mm exit pupil, inside the telescope's useful range.