This is taken from an old thread on S.A.A. "The older Celestron (mfg by Vixen) Orthoscopics were available in the mid/late
1980's in the 1.25" barrel format in the following sizes:
4mm, 5mm, 6mm, 7mm, 9mm, 12mm, 18mm, 25mm.
Celestron also listed at that time under Orthoscopic eyepieces it's 8.4mm -
21mm Zoom ocular. At one time or another I've had all of these, except for the
25mm and the Zoom."Here's the thread http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=NK8_5.103897%24hk4.3767341%40news.infostrada.it&rnum=6&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26q%3DCelestron%2BOrthos%2Bfl%26btnG%3DSearch
1980's in the 1.25" barrel format in the following sizes:
4mm, 5mm, 6mm, 7mm, 9mm, 12mm, 18mm, 25mm.
Celestron also listed at that time under Orthoscopic eyepieces it's 8.4mm -
21mm Zoom ocular. At one time or another I've had all of these, except for the
25mm and the Zoom."Here's the thread http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=NK8_5.103897%24hk4.3767341%40news.infostrada.it&rnum=6&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26q%3DCelestron%2BOrthos%2Bfl%26btnG%3DSearch