Eyepiece and telescope pairing

Celestron Omni 56mm Plossl in the Celestron NexStar 6SE: magnification and field

What the Celestron Omni 56mm Plossl does in the Celestron NexStar 6SE, worked from the published focal lengths and apparent field.

Field of view

ring = 1.75 degrees true
dot = 5.6 mm exit pupil

Computed optics

Magnification
27x1500 mm / 56 mm
True field
1.75 degrees47 deg / 27x
Exit pupil
5.6 mm150 mm / 27x
Max useful mag
354xpublished
Barrel match
2 in eyepiece in a 2 in focuser
Fits

Good fit. In the Celestron NexStar 6SE the Celestron Omni 56mm Plossl gives 27x with a 1.75 degree true field and a 5.6 mm exit pupil, inside the telescope's useful range.


Magnification is the telescope focal length divided by the eyepiece focal length: 1500 mm divided by 56 mm is 27x. The true field of view is the eyepiece's 47 degree apparent field divided by that magnification, 1.75 degrees.

The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 150 mm over 27x, which is 5.6 mm. That makes this a low-power, wide-field and deep-sky setting.