A Tele Vue 13mm Nagler Type 6 in the Celestron NexStar 4SE gives 102x, a 0.8 degree true field and a 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 13mm Nagler Type 6 in the Celestron NexStar 4SE: magnification and field

What the Tele Vue 13mm Nagler Type 6 does in the Celestron NexStar 4SE, worked from the published focal lengths and apparent field.

Field of view

ring = 0.8 degrees true
dot = 1 mm exit pupil

Computed optics

Magnification
102x1325 mm / 13 mm
True field
0.8 degrees82 deg / 102x
Exit pupil
1 mm102 mm / 102x
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 13mm Nagler Type 6 gives 102x with a 0.8 degree true field and a 1 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 13 mm is 102x. The true field of view is the eyepiece's 82 degree apparent field divided by that magnification, 0.8 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 102 mm over 102x, which is 1 mm. That makes this a high-power lunar, planetary and double-star setting.

The eyepiece to buy

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Related

Celestron NexStar 4SE102 mm f/13
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Best eyepiece for the Celestron NexStar 4SEexit-pupil match

Questions and answers

Tele Vue 13mm Nagler Type 6 in the Celestron NexStar 4SE: magnification and field?

Good fit. In the Celestron NexStar 4SE the Tele Vue 13mm Nagler Type 6 gives 102x with a 0.8 degree true field and a 1 mm exit pupil, inside the telescope's useful range.