Criterion AR eyepieces

I recently acquired a Criterion RV-6, it came with 2 eyepieces, an AR-9 mm and an AR-18mm. Measuring the field stops, the AFOV should be 38 and 35 degrees.

I am curious if anyone knows much about these eyepieces, what type they might be. They seem quite simple but provide pretty decent planetary detail without ghosting or reflection, at least that was my first impression.

jon

I have a RV-6 that my father bought for me in 1976. The eyepieces are Achromatic Ramsden. They consist of two cemented doublets. They work quite well in the f/8 RV-6.

Jon Isaacs said:

I recently acquired a Criterion RV-6, it came with 2 eyepieces, an AR-9 mm and an AR-18mm. Measuring the field stops, the AFOV should be 38 and 35 degrees.

jon