A Tele Vue 6mm Ethos in the Celestron NexStar 4SE gives 221x, a 0.45 degree true field and a 0.5 mm exit pupil. The worked calculation and whether it sits in the useful range.

Updated 05 September 2026.

Eyepiece and telescope pairing

Tele Vue 6mm Ethos in the Celestron NexStar 4SE: magnification and field

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

Field of view

ring = 0.45 degrees true
dot = 0.5 mm exit pupil

Computed optics

Magnification
221x1325 mm / 6 mm
True field
0.45 degrees100 deg / 221x
Exit pupil
0.5 mm102 mm / 221x
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 6mm Ethos gives 221x with a 0.45 degree true field and a 0.5 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 6 mm is 221x. The true field of view is the eyepiece's 100 degree apparent field divided by that magnification, 0.45 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 102 mm over 221x, which is 0.5 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
Tele Vue 6mm Ethos6 mm, 100 deg
Best eyepiece for the Celestron NexStar 4SEexit-pupil match

Questions and answers

Tele Vue 6mm Ethos in the Celestron NexStar 4SE: magnification and field?

Good fit. In the Celestron NexStar 4SE the Tele Vue 6mm Ethos gives 221x with a 0.45 degree true field and a 0.5 mm exit pupil, inside the telescope's useful range.