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Owl Astronomy Products 30mm UltraWide Eyepiece
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Being an amateur astronomer of relatively modest means over the course of my 25 or so years in the hobby, I’ve had some, but limited, experience with the premium level wide-angle eyepieces and currently own only 1, a 9mm type 1 Nagler that I’ve enjoyed very much over the years. My other eyepieces tend towards good quality, but with more modest fields of view. When I recently purchased a 120mm f/5 refractor, I thought it would be a good time to look for an eyepiece to maximize the field of view for those few very large objects as well as enabling the scope to practically function as its own finderscope. My favorite low power eyepiece, an Ultima 30mm is a fine eyepiece, and would give 20x, a 2.5 degree field of view and a 6mm exit pupil. The power and exit pupil are fine, but an even wider f.o.v. would be even better, but I knew a $600 31mm Nagler was out of the question, so I did some searching around the internet websites, newsgroups and forums. I finally happened upon the Owl Astronomy Products website and their line of inexpensive 80 degree eyepieces. Hmmm… 30mm… 80 degrees… I’d still get that 20x and 6mm exit pupil, but I could get it with a 4 degree f.o.v. rather than just 2.5 degrees. Though I knew there would be tradeoffs, for about $74 it seemed worth a try to me. So I place my order and bided my time.
Upon arrival a short time later, I was provisionally impressed. The eyepiece was well packed and felt substantial without being too heavy and came packaged in the bolt style screw on case, so it was well protected. These cases aren’t my favorite for field use, but they are nice for shipping or longer term storage and, to me, seems to indicate that the seller has given some care to protect their product. The eyepiece is advertised as being fully multi-coated and this appeared to be the case upon examination, with the air-to-glass surfaces I could see well coated and showing the typical green reflections in the right light. It is, of course, a 2” eyepiece.
On daytime targets, the eyepiece seemed to work well with my 120mm f/5 achromatic refractor. The eye relief is given as 28mm and that seemed about right to me. The view didn’t seem to suffer any particular blackout problems and wasn’t too sensitive to eye placement. The field stop is visible but not totally sharp. In daylight, I could see some aberrations as I neared the field stop, but they weren’t as bad as I might have thought. The true test, though, as we all know, is how it performs on stars, which are very unforgiving.
Under the stars, aberrations were, as expected, present and obvious, but not, to me, of great enough degree to make me reject the eyepiece. On the contrary, I enjoyed using it quite a bit. The outer third of the f.o.v. started showing noticeable aberrations with things getting worse and worse near the field stop, where stars would blur into streaks when I looked towards the edge—but, then again, this is a $74 ultra-wide field eyepiece in an f/5 scope. Compared to the 30mm Ultima, the Owl 30mm gave up some contrast and sky blackness and the stars at the edge of the Ultima f.o.v. were a bit sharper in the Ultima than the Owl 30mm… of course, the Owl 30mm showed an additional 30 degrees, a very substantial increase in the area of sky covered. I expected this tradeoff and it’s one I can live with. This extra f.o.v. was indispensable this summer when I screwed in a 2” OIII filter and had a breathtaking view of the entire Veil Nebula and the North American Nebula, the first time I was able to really see both objects well and obviously, with the shape of the North American Nebula being quite obvious instead of “yeah, I think that’s probably it, sort of”. The Owl 30mm and 120ST combo has also proved to give great dark-site views of the Andromeda and Pinwheel galaxies, as well as all other manner of the larger deep sky objects. It also allows me to use the 120ST as its own finder-scope when aligning the ASGT go-to mount I usually use it on, More often than not, the first alignment stars are within the 4 degree field of view, making things a bit easier for a lazy astronomer such as myself.
It comes down to this… this a good value eyepiece but doesn’t break the laws of physics and economics, either. If you demand edge to edge sharpness from an ultra-wide field eyepiece, you’ll be disappointed and should keep saving your money for a Nagler or comparable eyepiece. If, though, you want a wide-field eyepiece of much more modest cost that gives good performance with understandable trade-offs, then I’d urge you to give this eyepiece a look. At $74, if anything, I’d say it’s underpriced, though I was happy to only have to pay that much.