Optical reference
Sky-Watcher Flextube 300P (12-inch Dobsonian): aperture, focal length and eyepiece fit
What the Sky-Watcher Flextube 300P (12-inch Dobsonian) measures, the magnification and true field each eyepiece produces in it, and the barrel, mount payload and camera adapter that fit.
Published specifications
Eyepiece ladder
2 pairings| Pairing | Magnification | True field |
|---|---|---|
| Tele Vue 3.5mm Nagler Type 6 in the Sky-Watcher Flextube 300P (12-inch Dobsonian) | 429x | 0.19 deg |
| Tele Vue 10mm Delos in the Sky-Watcher Flextube 300P (12-inch Dobsonian) | 150x | 0.48 deg |
The Flextube 300P is a 305 mm f/4.9 collapsible Dobsonian, 12 in of aperture at a 1500 mm focal length that folds down for transport. Its light grasp reaches faint galaxies and its 2 in focuser takes the longest wide-field eyepieces.
Because magnification is the telescope's 1500 mm focal length divided by the eyepiece focal length, a 25 mm eyepiece gives 60x here and a 10 mm eyepiece gives 150x. The highest useful magnification is about 610x (roughly twice the aperture in millimetres), beyond which the image dims and softens without showing more detail.
The focuser takes 2 in eyepieces, so long 2 in wide-field eyepieces such as the Omni 56 mm fit as well as 1.25 in ones.