University Optics 40mm MK-70 40mm

I recently got interested in astronomy, and my first scope was a Jason 60mm departmental store refractor. Over time, I moved up to better scopes, including APO refractors, reflectors and catadioptrics. I think I've finally found my ideal scope, which is a Celestron C9.25. I have the advantage of dark skies, as I live in a really small town. :) A few months ago, I was in the market for a low magnification eyepiece. My first choice was the 31mm Nagler, but I couldn't afford the price. At well over $600, I could buy myself a whole collection of other astro equipment. The maximum I was willing to spend was around $200. A friend of mine suggested the MK-70, and I researched it thoroughly. This eyepiece provided me with the maximum true field of view at a very affordable price, and that was one of the main reasons why I purchased it. The Physical Appearance: The eyepiece looks like any other 2 incher, and weighs around 19 oz. Although I had to rebalance the scope after changing eyepieces, it doesn't bother me that much, as I use it the most, and hardly felt the need to change it. One of the few things I disliked about the eyepiece is the eyecup. Its made of hard rubber, and one has to work hard to slip it onto the eyepiece. Internal reflections didn't seem to be a problem with these eyepieces, as the lens edges and threads were blackened very well. Overall, it looked very promising, and I couldn't wait to look through it. The Optics: I've tried this eyepiece on several targets, and all I can say is "wow". It performed as well as the Naglers. In my f/10 scope, stars appeared as pinpoints to about 80% of the FOV. The fully multi-coated optics gave very high contrast images. I also used it along with the f/3.3 and f/6.3 focal reducers. At f/3.3, it was highly astigmatic, but there was improvement at f/6.3. All in all, I feel that this eyepiece performs well only in scopes of f/7 and slower. If you own a large slow SCT, this would make an ideal low power Nagler-like eyepiece. Overall, this eyepiece is definitely a cost effective way to get superior performance. I would recommend this eyepiece, only for slower scopes. (f/7 and slower)

Pros

1. The Cost
2. Great Contrast
3. Large FOV
4. Fully multi-coated Optics
5. Performance is Slow Scopes (f/7 and slower)
6. Extremely good low-power eyepiece

Cons

1. Very bad performance in faster scopes
2. Eyecup doesn't screw on easily
3. Balance Problems

Rating

-- End of review