A Celestron X-Cel LX 2.3mm in the Celestron StarSense Explorer DX 102AZ gives 287x, a 0.21 degree true field and a 0.4 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 2.3mm in the Celestron StarSense Explorer DX 102AZ: magnification and field

What the Celestron X-Cel LX 2.3mm does in the Celestron StarSense Explorer DX 102AZ, worked from the published focal lengths and apparent field.

Field of view

ring = 0.21 degrees true
dot = 0.4 mm exit pupil

Computed optics

Magnification
287x660 mm / 2.3 mm
True field
0.21 degrees60 deg / 287x
Exit pupil
0.4 mm102 mm / 287x
Max useful mag
241xpublished
Barrel match
1.25 in eyepiece in a 1.25 in focuser
No fit

Over-powered. At 287x this pair exceeds the published highest useful magnification of about 241x for the Celestron StarSense Explorer DX 102AZ, so the image dims and softens without showing more real detail. Use a longer eyepiece.


Magnification is the telescope focal length divided by the eyepiece focal length: 660 mm divided by 2.3 mm is 287x. The true field of view is the eyepiece's 60 degree apparent field divided by that magnification, 0.21 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 102 mm over 287x, which is 0.4 mm. That makes this a high-power lunar, planetary and double-star setting.

Questions and answers

Celestron X-Cel LX 2.3mm in the Celestron StarSense Explorer DX 102AZ: magnification and field?

Over-powered. At 287x this pair exceeds the published highest useful magnification of about 241x for the Celestron StarSense Explorer DX 102AZ, so the image dims and softens without showing more real detail. Use a longer eyepiece.