Eyepiece and telescope pairing
Celestron Omni 15mm Plossl in the Celestron C8 optical tube: magnification and field
What the Celestron Omni 15mm Plossl does in the Celestron C8 optical tube, worked from the published focal lengths and apparent field.
Field of view
ring = 0.37 degrees true
dot = 1.5 mm exit pupil
- Magnification
- 135x2032 mm / 15 mm
- True field
- 0.37 degrees50 deg / 135x
- Exit pupil
- 1.5 mm203 mm / 135x
- Max useful mag
- 480xpublished
Computed optics
- Barrel match
- 1.25 in eyepiece in a 2 in focuser
Good fit. In the Celestron C8 optical tube the Celestron Omni 15mm Plossl gives 135x with a 0.37 degree true field and a 1.5 mm exit pupil, inside the telescope's useful range.
Magnification is the telescope focal length divided by the eyepiece focal length: 2032 mm divided by 15 mm is 135x. The true field of view is the eyepiece's 50 degree apparent field divided by that magnification, 0.37 degrees.
The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 203 mm over 135x, which is 1.5 mm. That makes this a high-power lunar, planetary and double-star setting.
The eyepiece to buy
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