A Tele Vue 27mm Panoptic in the Celestron Omni XLT 120 gives 37x, a 1.84 degree true field and a 3.2 mm exit pupil. The worked calculation and whether it sits in the useful range.

Updated 05 September 2026.

Eyepiece and telescope pairing

Tele Vue 27mm Panoptic in the Celestron Omni XLT 120: magnification and field

What the Tele Vue 27mm Panoptic does in the Celestron Omni XLT 120, worked from the published focal lengths and apparent field.

Field of view

ring = 1.84 degrees true
dot = 3.2 mm exit pupil

Computed optics

Magnification
37x1000 mm / 27 mm
True field
1.84 degrees68 deg / 37x
Exit pupil
3.2 mm120 mm / 37x
Max useful mag
283xpublished
Barrel match
2 in eyepiece in a 2 in focuser
Fits

Good fit. In the Celestron Omni XLT 120 the Tele Vue 27mm Panoptic gives 37x with a 1.84 degree true field and a 3.2 mm exit pupil, inside the telescope's useful range.

Magnification is the telescope focal length divided by the eyepiece focal length: 1000 mm divided by 27 mm is 37x. The true field of view is the eyepiece's 68 degree apparent field divided by that magnification, 1.84 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 120 mm over 37x, which is 3.2 mm. That makes this a medium-power general setting.

The eyepiece to buy

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Related

Celestron Omni XLT 120120 mm f/8.3
Tele Vue 27mm Panoptic27 mm, 68 deg
Best eyepiece for the Celestron Omni XLT 120exit-pupil match

Questions and answers

Tele Vue 27mm Panoptic in the Celestron Omni XLT 120: magnification and field?

Good fit. In the Celestron Omni XLT 120 the Tele Vue 27mm Panoptic gives 37x with a 1.84 degree true field and a 3.2 mm exit pupil, inside the telescope's useful range.