If you aren't in a dark sky it is an extremely difficult object, and I had only seen it once in a dark sky through a 4" refractor. I had tried in the past to find it but never being sure I had the right starfield. However, real sharpness is confined only to the middle third of the field of view (assuming one focuses on the center of the field, rather than the edge or elsewhere).Īs a "finder" eyepiece, I was able to give it a rigorous task, helping me find NGC 188 under my light polluted sky. More importantly, star brightness towards the field edge is not seriously diminished. Field curvature, while still present and more noticeable than in the refractors, does not come across as so harshly. In the 80mm f/7.5 the eyepiece gave a true field of view of 4 degrees (just one degree less than the 50mm finder)!Īfter reading a review elsewhere of someone using an identical dobsonian who was much more satisfied with its performance, I decided to give it another shot with the f/5.9 looking at actual starfields rather than a twilight moon. There is a little chromatic aberration that may bother some. Field curvature was only slight at these f ratios with really pleasing wide field views both outside and in the city (the latter with a filter). The experience with the eyepiece on both these medium focus refractors was vastly improved. And I got to try it on someone else's 80mm f/7 ED (which is a little faster). I might have returned the 30mm (and the 16mm), but I own other scopes, including an 80mm f/7.5 ED refractor. Below are some other initial tests made with other telescopes. More recently I was able to put this eyepiece to effective use on the dob, but more on that in a moment. My initial conclusions above were made during twilight tests on the moon which was definitely NOT the best subject for this eyepiece. In this case f/6 is most definitely "fast". This eyepiece will disabuse them of that notion. Many would consider f/6 to be considered a "medium" f ratio. I was initially disappointed with the 30mm Ultrawide - it has one particular aberration in fast scopes that would seem to preclude its intended use, and that is field curvature - where objects near the edge of the field are severely out of focus relative to the center and vice versa. Now, I'm not expecting an aberration-free eyepiece at that price for an f/6 scope, and some forms of aberration such as edge astigmatism which I get using the Antares 25mm W70 are relatively acceptable. Middle aged eyes and a light polluted sky rules out longer focal length eyepieces, so I was hoping to maximize the field of view without washing out the contrast too much. In the 30mm I wanted a "finder" eyepiece (not for an actual finderscope obviously) for widefield views to quickly locate faint fuzzies. I purchased the 30mm as well as a 16mm Agena Ultra-Wide eyepiece for my new 8" f/5.9 dobsonian which, unlike my old dob, accepts 2" eyepieces. Cons:įield curvature gets worse under f/7. 4.0 Best in medium to slow F ratios Pros:Īffordable wide field views.
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