Product Description
Terrestrially, it is superb for detailed long-distance nature studies with the 80mm and 100mm Pentax spotting scopes under average lighting conditions.
Astronomically, it's an excellent high power lunar and planetary observing eyepiece with long focal length refractors, reflectors, or catadioptric scopes under average seeing conditions. Its 10mm focal length is an ideal match for an f/10 Schmidt-Cassegrain, providing 200x and a 1mm exit pupil that closely matches the resolution of the scope to that of your eye. Some of the larger globular clusters, such as M13, will fill its 0.35-degree field with such a scope. It is also exceptional for medium power viewing with short focal length refractors and fast focal ratio Dobsonian reflectors. It has seven lenses in a six group optical design for a very wide 70° field. It is regularly useful for astronomical observing with long focal length scopes, but below average seeing conditions may limit its performance somewhat. If so-so seeing is the norm where you observe, its 10mm focal length will often represent the maximum practical with a long focal length scope.
The long 20mm eye relief is ideal for those who must wear eyeglasses while observing due to astigmatism. Even those who do not wear glasses will find the long eye relief a comfortable change from the cramped eye relief that is typical of the usual short focal length eyepiece.
For terrestrial observing . . .
With an 80mm straight-through Pentax spotting scope this eyepiece provides 50x magnification and a 74' field of view at 1000 yards, which are the values given in the specifications to the left.
With the 80mm angled Pentax spotting scope this eyepiece provides 52x magnification and a 71' field of view at 1000 yards.
With the 100mm aperture Pentax spotting scope this eyepiece provides 63x magnification and a 58' field of view.
For astronomical observing . . .
The field of view of 70° degrees given in the specifications to the left is the apparent field of view. The actual field of view will be equal to that apparent field divided by the magnification of the eyepiece/telescope combination.
Tech Details
Barrel Size | 1.25" |
---|---|
Eye Relief | 20mm |
Field of view | 70 |
Field of view 1000 yards | 74' |
Focal Length | 10mm |
Number of optical elements | 7 |
Power | 50x terrestrially |
Weight | 13.8 oz |
Warranty | Limited Lifetime |
Reviews
I especially love the eye cup adjustment which is necessary due to the good eye relief. It is great as a high power eyepiece. (Posted on 10/31/2019)
I have compared this eyepiece to comparable Delos and Naglers, and this one is every bit as good. If you can swallow the steep asking price, it's a real keeper. (Posted on 9/1/2019)
I find it's even pretty good on planets/moon which is impressive for a wide field. I've had the 10, 7 and 5mm and all were very good. (Posted on 11/1/2018)
Great eyepiece. I have been working towards the AL Galaxy Clusters Award, and the EP has been a valuable assistant! Great contrast. Stars are pinpoint edge to edge. Well made. I don't wear eyeglasses except for reading, and I was uncomfortable with a "tunnel vision" effect, until I remembered the adjustable eyecup. Adjusting the eyecup made a good eyepiece a GREAT eyepiece. I would replace it with the same one if I ever lost it! (Posted on 8/4/2017)