A Celestron X-Cel LX 12mm in the Celestron C6 optical tube gives 125x, a 0.48 degree true field and a 1.2 mm exit pupil. The worked calculation and whether it sits in the useful range.

Updated 05 September 2026.

Eyepiece and telescope pairing

Celestron X-Cel LX 12mm in the Celestron C6 optical tube: magnification and field

What the Celestron X-Cel LX 12mm does in the Celestron C6 optical tube, worked from the published focal lengths and apparent field.

Field of view

ring = 0.48 degrees true
dot = 1.2 mm exit pupil

Computed optics

Magnification
125x1500 mm / 12 mm
True field
0.48 degrees60 deg / 125x
Exit pupil
1.2 mm150 mm / 125x
Max useful mag
354xpublished
Barrel match
1.25 in eyepiece in a 1.25 in focuser
Fits

Good fit. In the Celestron C6 optical tube the Celestron X-Cel LX 12mm gives 125x with a 0.48 degree true field and a 1.2 mm exit pupil, inside the telescope's useful range.

Magnification is the telescope focal length divided by the eyepiece focal length: 1500 mm divided by 12 mm is 125x. The true field of view is the eyepiece's 60 degree apparent field divided by that magnification, 0.48 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 150 mm over 125x, which is 1.2 mm. That makes this a high-power lunar, planetary and double-star setting.

The eyepiece to buy

Shop Celestron X-Cel LX 12mm on AmazonaffiliateFind Celestron X-Cel LX 12mm on eBayaffiliate

Related

Celestron C6 optical tube150 mm f/10
Celestron X-Cel LX 12mm12 mm, 60 deg
Best eyepiece for the Celestron C6 optical tubeexit-pupil match

Questions and answers

Celestron X-Cel LX 12mm in the Celestron C6 optical tube: magnification and field?

Good fit. In the Celestron C6 optical tube the Celestron X-Cel LX 12mm gives 125x with a 0.48 degree true field and a 1.2 mm exit pupil, inside the telescope's useful range.