A Tele Vue 12mm Delos in the Sky-Watcher Classic 150P (6-inch Dobsonian) gives 100x, a 0.72 degree true field and a 1.5 mm exit pupil. The worked calculation and whether it sits in the useful range.

Updated 05 September 2026.

Eyepiece and telescope pairing

Tele Vue 12mm Delos in the Sky-Watcher Classic 150P (6-inch Dobsonian): magnification and field

What the Tele Vue 12mm Delos does in the Sky-Watcher Classic 150P (6-inch Dobsonian), worked from the published focal lengths and apparent field.

Field of view

ring = 0.72 degrees true
dot = 1.5 mm exit pupil

Computed optics

Magnification
100x1200 mm / 12 mm
True field
0.72 degrees72 deg / 100x
Exit pupil
1.5 mm152 mm / 100x
Max useful mag
about 304x2x aperture
Barrel match
1.25 in eyepiece in a 2 in focuser
Fits

Good fit. In the Sky-Watcher Classic 150P (6-inch Dobsonian) the Tele Vue 12mm Delos gives 100x with a 0.72 degree true field and a 1.5 mm exit pupil, inside the telescope's useful range.

Magnification is the telescope focal length divided by the eyepiece focal length: 1200 mm divided by 12 mm is 100x. The true field of view is the eyepiece's 72 degree apparent field divided by that magnification, 0.72 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 152 mm over 100x, which is 1.5 mm. That makes this a medium-power general setting.

The eyepiece to buy

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Related

Sky-Watcher Classic 150P (6-inch Dobsonian)152 mm f/7.9
Tele Vue 12mm Delos12 mm, 72 deg
Best eyepiece for the Sky-Watcher Classic 150P (6-inch Dobsonian)exit-pupil match

Questions and answers

Tele Vue 12mm Delos in the Sky-Watcher Classic 150P (6-inch Dobsonian): magnification and field?

Good fit. In the Sky-Watcher Classic 150P (6-inch Dobsonian) the Tele Vue 12mm Delos gives 100x with a 0.72 degree true field and a 1.5 mm exit pupil, inside the telescope's useful range.