Eyepiece and telescope pairing
Tele Vue 7mm Nagler Type 6 in the Orion SpaceProbe 130ST: magnification and field
What the Tele Vue 7mm Nagler Type 6 does in the Orion SpaceProbe 130ST, worked from the published focal lengths and apparent field.
Field of view
ring = 0.88 degrees true
dot = 1.4 mm exit pupil
- Magnification
- 93x650 mm / 7 mm
- True field
- 0.88 degrees82 deg / 93x
- Exit pupil
- 1.4 mm130 mm / 93x
- Max useful mag
- about 260x2x aperture
Computed optics
- Barrel match
- 1.25 in eyepiece in a 1.25 in focuser
Good fit. In the Orion SpaceProbe 130ST the Tele Vue 7mm Nagler Type 6 gives 93x with a 0.88 degree true field and a 1.4 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 7 mm is 93x. The true field of view is the eyepiece's 82 degree apparent field divided by that magnification, 0.88 degrees.
The exit pupil, the width of the light beam leaving the eyepiece, is the aperture divided by the magnification, 130 mm over 93x, which is 1.4 mm. That makes this a high-power lunar, planetary and double-star setting.
The eyepiece to buy
Shop Tele Vue 7mm Nagler Type 6 on AmazonaffiliateFind Tele Vue 7mm Nagler Type 6 on eBayaffiliate