Eyepiece and telescope pairing
Celestron X-Cel LX 12mm in the Celestron NexStar Evolution 9.25: magnification and field
What the Celestron X-Cel LX 12mm does in the Celestron NexStar Evolution 9.25, worked from the published focal lengths and apparent field.
Field of view
ring = 0.31 degrees true
dot = 1.2 mm exit pupil
- Magnification
- 196x2350 mm / 12 mm
- True field
- 0.31 degrees60 deg / 196x
- Exit pupil
- 1.2 mm235 mm / 196x
- Max useful mag
- 555xpublished
Computed optics
- Barrel match
- 1.25 in eyepiece in a 2 in focuser
Good fit. In the Celestron NexStar Evolution 9.25 the Celestron X-Cel LX 12mm gives 196x with a 0.31 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: 2350 mm divided by 12 mm is 196x. The true field of view is the eyepiece's 60 degree apparent field divided by that magnification, 0.31 degrees.
The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 235 mm over 196x, which is 1.2 mm. That makes this a high-power lunar, planetary and double-star setting.
The eyepiece to buy
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