Pentax 10mm XW extra wide angle eyepiece


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This short focal length Pentax is a high power eyepiece usable for both terrestrial and astronomical observing . . .
Our Product #: PXW10
Pentax Product #: 70514
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Product Description

This short focal length Pentax is a high power eyepiece usable for both terrestrial and astronomical observing.

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


Review by:
The XW10 is a fantastic eyepiece with top quality optics and unsurpassed comfort. Eye relief is excellent and the adjustable eye guard allows you to fine tune to the most optimal position. Contrast and transmission are superb and images are super sharp across the 70 degree AFOV. The 10mm focal length makes it a great choice for just about any scope.

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)
Review by:
This eyepiece gives superbly clean views with no lateral color. I wear eyeglasses when I observe and so need the eye relief. I use the eyepiece on a 6-inch f/8 Newt, an 80mm ED refractor, and a 290mm Classical Cassegrain. I'm always impressed by the sharp views of the Double Double. This is my most-used eyepiece. (Posted on 8/14/2019)
Review by:
It comes up a lot in discussions on Cloudynights and is a frequent contender for "top ten eyepieces ever made." If you are are a person who knows the major brand lines (Ethos, Delos, Morpheus, ES, Celestron, Meade, etc.) then you have heard of Pentax and you have heard of the XW series and you don't need any coaching in how to make up your mind. But if you have had only a few of the comes-with eyepieces that were included with your scope or have been limited to the entry and low end options and are finally coming to a point where you don't faint at $300 for an eyepiece, this is the one for you. It is terrific in just about any scope, fast or slow, and razor sharp. It has fantastic ergonomics and eye relief. The removable top upper ring makes it easy to clean. Less well known: the inner metal ring on top of the eyepiece unscrews and can be fitted with an adapter so that you can shoot directly with a camera (a real camera, not a smart phone). About the only limitation is that in a c14 the magnification is a tad high (391x) for most nights. But for focal lengths under 3000 mm this is going to be a great ocular and is a pleasure to use in apos as well. I have observed with novices in our local outreach program and they had great reluctance to part with this ocular after getting a chance to use it in their Orion XT 6 and 8 inch dobs. What I mean by that is that it's an eyepiece which "sells itself" to novices and seasoned observers alike. And it says something that this line of oculars, which gets no advertising budget or support from Pentax (unlike spreads you see in magazines), essentially sells itself on word of mouth. The XW line in general is the eyepiece line that convinced many observers and many in the industry that the wave of ever-expanding fields of view (82 degrees, 100 degrees, etc.) had gone too far and that an extremely well executed 70 degree field was a great place to be. (Posted on 4/17/2019)
Review by:
This is a great classic eyepiece. These have been around for a long time (wish they brought back the 40 and 30mm versions). If you find the Delos eyecup annoying like I do, the Pentax is a twist up cup. I like that design more. The performance is just as good in my opinion.

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)
Review by:
I find the XW series of Pentax eyepieces to be very comfortable with ample eye relief for both glasses wearers and non glasses wearers. There is a nice adjustable guide that helps you get your eye placed in the perfect spot to use. The view is spectacular in my refractors and reflectors. (Posted on 10/6/2018)
Review by:
The entire Pentax XW eyepiece line is fantastic for eyeglass wearers with astigmatism, because there is enough eye relief to see the entire field of view with glasses on. Also, the 10mm version is an outstanding eyepiece regardless of eyeglasses - probably the best in the line. (Posted on 10/6/2018)
Review by:
This was my first Pentax eyepiece. I bought this after looking through the same EP belonging to a friend. I was not disappointed! Shortly after purchase, I had an opportunity to compare this with an Ethos 10mm in my 18 inch Starmaster telescope. Other than the Ethos having a wider field of view, the two eyepieces gave identical views of a variety of objects. A couple other seasoned astronomers looked at the same objects and agreed with me.

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)
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