Eyepiece and telescope pairing
Celestron X-Cel LX 25mm in the Celestron AstroMaster 130EQ: magnification and field
What the Celestron X-Cel LX 25mm does in the Celestron AstroMaster 130EQ, worked from the published focal lengths and apparent field.
Field of view
ring = 2.31 degrees true
dot = 5 mm exit pupil
- Magnification
- 26x650 mm / 25 mm
- True field
- 2.31 degrees60 deg / 26x
- Exit pupil
- 5 mm130 mm / 26x
- Max useful mag
- 307xpublished
Computed optics
- Barrel match
- 1.25 in eyepiece in a 1.25 in focuser
Good fit. In the Celestron AstroMaster 130EQ the Celestron X-Cel LX 25mm gives 26x with a 2.31 degree true field and a 5 mm exit pupil, inside the telescope's useful range.
Magnification is the telescope focal length divided by the eyepiece focal length: 650 mm divided by 25 mm is 26x. The true field of view is the eyepiece's 60 degree apparent field divided by that magnification, 2.31 degrees.
The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 130 mm over 26x, which is 5 mm. That makes this a low-power, wide-field and deep-sky setting.
The eyepiece to buy
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