Eyepiece and telescope pairing
Best eyepiece for the Celestron NexStar Evolution 9.25
Which eyepiece gets the most out of the Celestron NexStar Evolution 9.25, chosen by exit pupil rather than by guesswork.
- Aperture / focal length
- 235 mm / 2350 mm (f/10)
- Deep-sky pick
- Tele Vue 20mm Plossl: 118x, 2 mm exit pupil
- Low-power pick
- Tele Vue 55mm Plossl: 43x, 5.5 mm exit pupil
- Focuser barrel
- 2 in (both eyepieces fit)
For deep-sky detail, the Tele Vue 20mm Plossl is the pick of the eyepieces here: at 118x it lands near the 2 mm exit pupil where faint-object contrast peaks in the Celestron NexStar Evolution 9.25. For wide low-power sweeping, drop to the Tele Vue 55mm Plossl at 43x.
An exit pupil near 2 mm is the classic sweet spot for teasing detail out of faint deep-sky objects, because it concentrates the light while keeping the image bright enough. In the Celestron NexStar Evolution 9.25 the Tele Vue 20mm Plossl lands there, at 118x with a 2 mm exit pupil and a 0.43 degree field.
For a low-power finder-and-framing view you want a wider exit pupil, around 5 mm. Here the Tele Vue 55mm Plossl gives 43x, a 5.5 mm exit pupil and a 1.17 degree field, the widest true field of the eyepieces that fit this focuser.