Eyepiece and telescope pairing
Best eyepiece for the Sky-Watcher Flextube 300P (12-inch Dobsonian)
Which eyepiece gets the most out of the Sky-Watcher Flextube 300P (12-inch Dobsonian), chosen by exit pupil rather than by guesswork.
- Aperture / focal length
- 305 mm / 1500 mm (f/4.9)
- Deep-sky pick
- Tele Vue 10mm Delos: 150x, 2.03 mm exit pupil
- Low-power pick
- Celestron X-Cel LX 25mm: 60x, 5.08 mm exit pupil
- Focuser barrel
- 2 in (both eyepieces fit)
For deep-sky detail, the Tele Vue 10mm Delos is the pick of the eyepieces here: at 150x it lands near the 2 mm exit pupil where faint-object contrast peaks in the Sky-Watcher Flextube 300P (12-inch Dobsonian). For wide low-power sweeping, drop to the Celestron X-Cel LX 25mm at 60x.
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 Sky-Watcher Flextube 300P (12-inch Dobsonian) the Tele Vue 10mm Delos lands there, at 150x with a 2.03 mm exit pupil and a 0.48 degree field.
For a low-power finder-and-framing view you want a wider exit pupil, around 5 mm. Here the Celestron X-Cel LX 25mm gives 60x, a 5.08 mm exit pupil and a 1 degree field, the widest true field of the eyepieces that fit this focuser.