Recently I bought two 16mm widescan III eyepieces for use with my soon to be delivered Denk II's. Using a Celestron 8" SCT, I tried out the new eyepiece in mono mode and was delighted. Very bright field, fairly wide field, and a crisp image of Jupiter almost to the edge of the field. The eyepiece has an 84 deg apparent field. All this is the good.
My Denk II's arrived and the first night was one of experimenting with different eyepieces and learning the ins and outs of the power switches. I tried a pair of 19mm Pans, 12 mm Orthos and the pair of 16mm Widescans. The Pans and Orthos worked great, no complaints.
Now for the bad. The 16mm Widescans gave me a big problem. The first thing I noticed was that the eye spacing on the Denks became very critical. I mean really touchy. A little change and the view tended to black out. Then, most distressing, when the image moved toward the outer part of the field, it became very difficult to follow with my eyes. Lots of blacking out. My guess is that about 2/3 of the field is fine, but as soon as my eye shifted to follow the image across the field, problems.
Is this effect because of the 84 deg apparent field of the eyepiece? Would this same effect be present in a Nagler(82 deg)?
By the way, the Widescan eye relief is not excessive. I would describe it as just adequate.
Russ Schnitzer
My Denk II's arrived and the first night was one of experimenting with different eyepieces and learning the ins and outs of the power switches. I tried a pair of 19mm Pans, 12 mm Orthos and the pair of 16mm Widescans. The Pans and Orthos worked great, no complaints.
Now for the bad. The 16mm Widescans gave me a big problem. The first thing I noticed was that the eye spacing on the Denks became very critical. I mean really touchy. A little change and the view tended to black out. Then, most distressing, when the image moved toward the outer part of the field, it became very difficult to follow with my eyes. Lots of blacking out. My guess is that about 2/3 of the field is fine, but as soon as my eye shifted to follow the image across the field, problems.
Is this effect because of the 84 deg apparent field of the eyepiece? Would this same effect be present in a Nagler(82 deg)?
By the way, the Widescan eye relief is not excessive. I would describe it as just adequate.
Russ Schnitzer
