Test
Results
Art.–Nr. PEN-XO-5
Pentax XO 5.1mm
Sharpness:
Perfect up to the edge. At 5mm it is simply not possible to get a better
result.
x-axis: distance from optical
axis in °, y-axis: resolution in arc minutes
Apparent Field of View:
The measured apparent field of view is approx. 42°, somewhat less than
the 44° given by Pentax.
Contrast:
For a 5mm eyepiece: outstanding! That’s real an eyepiece for planetary
observations.
Aberration:
If you are very precise: a small field curvature may need to shift the
focus from the center towards the edges. But this will depend on the telescope
in use also.
Eye Relief:
Not the right one if you have to wear glasses. The eye relief of 3.6mm
makes it like driving a Ferrari: pure power without any comfort.
Mechanical Quality:
That’s nothing we have to report on earnestly for Pentax eyepieces.
Small, but perfect.
Summary:
Surely an eyepiece for purists. Structures on planets, which you will
not identify with this eyepiece, you won’t get with another one. The absolute
sharpness combined with highest contrast makes this eyepiece clearly a high-end
one.