Eyepiece and telescope pairing
Celestron Omni 4mm Plossl in the Celestron AstroMaster 114EQ: magnification and field
What the Celestron Omni 4mm Plossl does in the Celestron AstroMaster 114EQ, worked from the published focal lengths and apparent field.
Field of view
ring = 0.2 degrees true
dot = 0.5 mm exit pupil
- Magnification
- 250x1000 mm / 4 mm
- True field
- 0.2 degrees50 deg / 250x
- Exit pupil
- 0.5 mm114 mm / 250x
- Max useful mag
- 269xpublished
Computed optics
- Barrel match
- 1.25 in eyepiece in a 1.25 in focuser
Good fit. In the Celestron AstroMaster 114EQ the Celestron Omni 4mm Plossl gives 250x with a 0.2 degree true field and a 0.5 mm exit pupil, inside the telescope's useful range.
Magnification is the telescope focal length divided by the eyepiece focal length: 1000 mm divided by 4 mm is 250x. The true field of view is the eyepiece's 50 degree apparent field divided by that magnification, 0.2 degrees.
The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 114 mm over 250x, which is 0.5 mm. That makes this a high-power lunar, planetary and double-star setting.
The eyepiece to buy
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