Bob:

The Edmund Scientific Company recently reorganized. Edmund Industrial Optics was spun out and now owns the "RKE" trademark and assets. The former consumer scientific product portion of the business has become just another retailer, now selling Meade, Celestron and other manufacturers' products.

As for RKE eyepieces, they are still made by the Edmund Industrial Optics group, but the price has risen from $39 in the old days to $57 currently. When ordered they come in boxes wrapped in paper with no plastic eyepiece case. Be forewarned.

Before getting into the benefits aspect of this post, I should point out that Edmund Industrial Optics also sells a 2" Erfle under the "RKE" brand, but it really is not an "RKE" eyepiece. "RKE" stands for “Rank Kellner Eyepiece” and is named after the Edmund scientist who came up with the design, Dr. David Rank. It is a modified (reversed lens order) 3 element Kellner design. This post focuses on the 1.25” RKE eyepieces of Rank’s design.

As noted by others responding to your post, these do give a narrower apparent field of view than Plossls or wide angle designs. That said, they are absolutely superb for splitting double stars and viewing the moon and planets. No stray internal reflections. Simple 3-element lens system that passes more light through to your eye than thick multi-lens systems. I find them to be FAR SUPERIOR to Plossls, wide angles (Naglers, etc.) and even the vaunted University Optics Orthoscopics on lunar and planetary subjects.

At $39 they were a steal. At $57 the field of price-competitive alternatives opens up quite a bit. Still, I think they represent great value. For reference I use them with an 80mm f9.4 achromatic refractor and an 8” Schmidt-Cassegrain. For further investigation I recommend the following review in which several observers using extremely high end large refractors from Takahashi and Astro-Physics ($$$$$), and conclude that the RKE beat every single eyepiece on planetary study (including Naglers, Takahashi LEs, Pentax XLs and other $200+ units), and was only surpassed by the Zeiss Orthoscopics.

http://www.cloudynights.com/eyepieces2/planetary.htm

No affiliations with Edmund Optics, etc.

Jim