Eyepiece and telescope pairing
Tele Vue 32mm Plossl in the Sky-Watcher Evostar 72ED: magnification and field
What the Tele Vue 32mm Plossl does in the Sky-Watcher Evostar 72ED, worked from the published focal lengths and apparent field.
Field of view
ring = 3.81 degrees true
dot = 5.5 mm exit pupil
- Magnification
- 13x420 mm / 32 mm
- True field
- 3.81 degrees50 deg / 13x
- Exit pupil
- 5.5 mm72 mm / 13x
- Max useful mag
- 170xpublished
Computed optics
- Barrel match
- 1.25 in eyepiece in a 2 in focuser
Good fit. In the Sky-Watcher Evostar 72ED the Tele Vue 32mm Plossl gives 13x with a 3.81 degree true field and a 5.5 mm exit pupil, inside the telescope's useful range.
Magnification is the telescope focal length divided by the eyepiece focal length: 420 mm divided by 32 mm is 13x. The true field of view is the eyepiece's 50 degree apparent field divided by that magnification, 3.81 degrees.
The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 72 mm over 13x, which is 5.5 mm. That makes this a low-power, wide-field and deep-sky setting.
The eyepiece to buy
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