A Celestron Omni 32mm Plossl in the Celestron C5 optical tube gives 39x, a 1.23 degree true field and a 3.3 mm exit pupil. The worked calculation and whether it sits in the useful range.

Updated 05 September 2026.

Eyepiece and telescope pairing

Celestron Omni 32mm Plossl in the Celestron C5 optical tube: magnification and field

What the Celestron Omni 32mm Plossl does in the Celestron C5 optical tube, worked from the published focal lengths and apparent field.

Field of view

ring = 1.23 degrees true
dot = 3.3 mm exit pupil

Computed optics

Magnification
39x1250 mm / 32 mm
True field
1.23 degrees48 deg / 39x
Exit pupil
3.3 mm127 mm / 39x
Max useful mag
295xpublished
Barrel match
1.25 in eyepiece in a 1.25 in focuser
Fits

Good fit. In the Celestron C5 optical tube the Celestron Omni 32mm Plossl gives 39x with a 1.23 degree true field and a 3.3 mm exit pupil, inside the telescope's useful range.

Magnification is the telescope focal length divided by the eyepiece focal length: 1250 mm divided by 32 mm is 39x. The true field of view is the eyepiece's 48 degree apparent field divided by that magnification, 1.23 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 127 mm over 39x, which is 3.3 mm. That makes this a medium-power general setting.

The eyepiece to buy

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Related

Celestron C5 optical tube127 mm f/10
Celestron Omni 32mm Plossl32 mm, 48 deg
Best eyepiece for the Celestron C5 optical tubeexit-pupil match

Questions and answers

Celestron Omni 32mm Plossl in the Celestron C5 optical tube: magnification and field?

Good fit. In the Celestron C5 optical tube the Celestron Omni 32mm Plossl gives 39x with a 1.23 degree true field and a 3.3 mm exit pupil, inside the telescope's useful range.