A Tele Vue 11mm Nagler Type 6 in the Celestron C5 optical tube gives 114x, a 0.72 degree true field and a 1.1 mm exit pupil. The worked calculation and whether it sits in the useful range.

Updated 05 September 2026.

Eyepiece and telescope pairing

Tele Vue 11mm Nagler Type 6 in the Celestron C5 optical tube: magnification and field

What the Tele Vue 11mm Nagler Type 6 does in the Celestron C5 optical tube, worked from the published focal lengths and apparent field.

Field of view

ring = 0.72 degrees true
dot = 1.1 mm exit pupil

Computed optics

Magnification
114x1250 mm / 11 mm
True field
0.72 degrees82 deg / 114x
Exit pupil
1.1 mm127 mm / 114x
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 Tele Vue 11mm Nagler Type 6 gives 114x with a 0.72 degree true field and a 1.1 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 11 mm is 114x. The true field of view is the eyepiece's 82 degree apparent field divided by that magnification, 0.72 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 127 mm over 114x, which is 1.1 mm. That makes this a high-power lunar, planetary and double-star setting.

The eyepiece to buy

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Questions and answers

Tele Vue 11mm Nagler Type 6 in the Celestron C5 optical tube: magnification and field?

Good fit. In the Celestron C5 optical tube the Tele Vue 11mm Nagler Type 6 gives 114x with a 0.72 degree true field and a 1.1 mm exit pupil, inside the telescope's useful range.