Eyepiece and telescope pairing

Celestron X-Cel LX 25mm in the Celestron C6 optical tube: magnification and field

What the Celestron X-Cel LX 25mm does in the Celestron C6 optical tube, worked from the published focal lengths and apparent field.

Field of view

ring = 1 degrees true
dot = 2.5 mm exit pupil

Computed optics

Magnification
60x1500 mm / 25 mm
True field
1 degrees60 deg / 60x
Exit pupil
2.5 mm150 mm / 60x
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 25mm gives 60x with a 1 degree true field and a 2.5 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 25 mm is 60x. The true field of view is the eyepiece's 60 degree apparent field divided by that magnification, 1 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 150 mm over 60x, which is 2.5 mm. That makes this a medium-power general setting.