The eyepieces that Jim Gibson and I compared last night were a Gary Russell 13mm Super Wide Angle and a Nagler 13mm Type 6. Primarily the comparison was made viewing the moon, but I spent some time viewing other objects as well. The tests were performed with Jim Gibson's Orion 80mm ED scope with a William Optics 2" star diagonal supported by a Chuck Hards mount. The initial impression of both eyepieces, and of the Orion 80mm ED scope are that they are very impressive. The amount of detail and resolution through this scope is amazing especially considering it's aperture. Both eyepieces in this scope produced pinpoint stars to the edge of the field of view, but from experience, I do know that the 13mm SWA does have some comma in the outer 10% FOV on an F4 scope, but this is most likely due to the scope, not the eyepiece. Initially, the first thing that I noticed was that the Nagler eyepiece had a slight yellowish tint while the 13mm had a slight blue tint. This was only apparent immediately after switching the eyepieces, and this impression disappeared a few seconds after the switch. The focal length between the two eyepieces were slightly different with the Nagler providing a slightly lower magnification. I suspect that the 13mm eyepiece is probably closer to 12mm than 13. Both eyepieces had some off axis chromatic aberrations with the Nagler being slightly better corrected. The 80mm scope provided virtually no chromatic aberrations at all when viewing both the moon and Venus. While I did not specifically look for it, the apparent field of view in both eyepieces is wide enough that the edge just about disappears, and did not bring attention to the fact that you were looking through a telescope, not directly at the heavens. The Nagler did provide a slight edge over the Gary Russell 13mm in resolution and detail, but I had to look long and hard at specific features on the moons surface to see the difference, and this was only on very small features. At first glance, they provided virtually identical views. Just about the only other difference I could see between the two eyepieces is that the Gary Russell 13mm did have some very slight internal reflections visible, which I think was actually a reflection of my eyeball being reflected off of one of the surfaces in the eyepiece as this moved with my eyeball. The Nagler also had a very slight edge in the darkness of the sky which was very bright there at Fort Utah. My conclusions ... The Nagler 13mm Type 6 is one awesome eyepiece. But if your budget does not have enough room to purchase the Nagler, the Gary Russell 13mm SWA ($85) is a very close competitor, and unless you do direct side by side comparisons, I doubt that you will ever notice the differences between these two eyepieces. You can purchase the Gary Russell eyepieces from his site at http://www.ctaz.com/~optics (I do not have any affiliation with Gary Russell other than owning several of his eyepiece, all of which have performed wonderfully. His best eyepiece is his 19mm SWA which we did not compare last night, but performs better than the 13mm SWA, and is the eyepiece found in my scopes 95% of the time.) If anyone wants to take a look through one of his eyepieces, or any eyepiece in my collection, please feel free to ask at any star party we are at, and I will be happy to let you take a look through them in both my scopes and yours. John Zeigler www.johnstelescopes.com www.mirrorkits.com