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.
So if you want to buy from them, make sure it is absolutely 1000% going to work for your setup, otherwise you might lose a few hundred bucks on a return.4.0 Best in medium to slow F ratios Pros:Īffordable wide field views. But there's plenty of other shops out there like Starizona who will accept a returned item, no questions asked.
Not sure how this is possible considering I never even attached the camera to my guidescope. When they got the item back, even though i had never used it, they claimed it had shown signs of "wear" and added the restocking fee. I tried to return an ASI 290mm in exchange for an ASI 174mm. For instance, you can't be sure that your guide camera/scope can work with your setup. However in astronomy, a very technical hobby where items don't always work, returns are often needed. I understand smaller shops have to compensate for lost $ with opened items. This is a problem, especially if you're buying very expensive items, that 10-20% restocking fee can quickly add up to hundreds of dollars. They also charge 10-15% above market value on amazon to compensate for amazons cut. On amazon, they will slap on a restocking fee even if you returned the item unopened. However, they do NOT like when you return things, and will often slap a 15% restocking fee onto whatever you returned, no matter the condition. Items were shipped quickly and they were very efficient. The first several times I bought from them, I had 0 problems. They seem to be a popular vendor on Amazon as well as in the astronomy community. Just wanted to warn everyone about buying from Agena Astro.
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