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Edmund Optics RKE |
Review date: September 2007
Purchase date: March 2007
Retailer: Ordered directly from Edmund Optics
Price: US$57.50 each
Eyepieces can be the most gimmicky part of the retail telescope world. Some manufacturers put little-to-no research behind their eyepiece design, simply sell what others make, don't concern themselves with glass types, or all of the above. Fortunately, there are a handful (and more these days than there used to be) of manufacturers who make or even design their own eyepieces, ensure optical quality, and take care to release a finished product with high standards.
Another interesting aspect of the telescope eyepiece market is the shift toward "space walk" views; apparent fields of view so wide that you have to move your head around to take it all in. Some of the eyepieces in this arena are excellent and yield astounding views, especially of extended objects like star clusters, nebulae, and large galaxies. The problem with these eyepieces is that they can cost as much as a decent, small APO refractor. Other eyepieces in this arena are clearly just tagging along, trying to jump on the bandwagon. It's easy to be tempted by some of the inexpensive, 2", ultra-wide FOV eyepieces you see advertised in the back of the astronomy mags. But with most of them, you'll only find out that the contrast is crap and the center 20% of the field is the only place where stars don't look like comets hurtling toward the middle of the field of view.
Then there is the Edmund Optics RKE line of eyepieces. These are extremely inexpensive eyepieces that pack a lot of punch. I bought the 15mm, 21mm, and 28mm eyepieces. The 28mm is my favorite but they all provide great views with little field curvature, very tolerable color control, and good eye relief all in a lightweight, 1.25" package. You can get all of the details on the Edmund Optics Web site.
- What I Like:
- Price—At only US$60, they're a marvel.
- Optics—RKE eyepieces are well-corrected, lightweight (due to having only 3 elements), and all-purpose. The 45° apparent field of view isn't huge but the contrast and sharpness throughout the field make these eyepieces no-brainers for lunar, planetary, and even deep sky applications. The 28mm stands out as a great semi-widefield eyepiece that is very comfortable to use.
- Overall Package—The eyepieces are sturdy and compact without that feeling of cheapness that seems to accompany so many other inexpensive eyepieces.
- What I'm Not Thrilled About:
- The 15mm—The three RKE eyepieces I've used are all great but on the 15mm you have to get in quite close to get a good view. The eye relief is still good at 13.4mm but you do feel like your eye is practically pressing into the eyepiece when using it.
Conclusion:
The 15mm, 21mm, and 28mm Edmund Optics RKE eyepieces are excellent buys. They are not the best eyepieces you'll ever buy, but they are well-made, provide excellent views with good contrast and sharpness, have long eye relief, and are inexpensive... a combination that's difficult to find. The 15mm eyepiece has good eye relief but it can still feel a little like you're not getting the full FOV unless you get in really close. In a world of US$600 eyepieces with 100° of AFOV, it's nice to have the option of using a high-quality eyepiece for only US$60. So they only have an AFOV of 45°... is twice the AFOV worth 10 times the cost? Don't get me wrong, I love the Naglers and Panoptic that I have, but I find myself using the RKEs about as often and am impressed every time I use them.
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Click an image below for a larger view.
 RKE 15, 21, and 28mm eyepieces
 RKE 15mm eyepiece
 RKE 21mm eyepiece
 RKE 28mm eyepiece
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