A Tele Vue 7mm Nagler Type 6 in the Orion SpaceProbe 130ST gives 93x, a 0.88 degree true field and a 1.4 mm exit pupil. The worked calculation and whether it sits in the useful range.

Updated 05 September 2026.

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

Computed optics

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
Barrel match
1.25 in eyepiece in a 1.25 in focuser
Fits

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.

Questions and answers

Tele Vue 7mm Nagler Type 6 in the Orion SpaceProbe 130ST: magnification and field?

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.