Built before the fall of Berlin wall, they were in stock in RDA in a shop that now sell old CZJ microscopes and astronomics parts
They were first built for microscopy and switched to astronomy back and forth to exhaust the stock.
It has been independantly tested by fellow astronomer (planetary specialist) and appears sharper and field corrected than any eudiascopic/erfle (Baader eudiascopic 20mm, Vixen LV 4mm without barlow, intes 21mm) and even a 25mm Tani Ortho
Original Price 130DM before Berlin wall fell.
It is similar to the Intes-Micro 18mm CJR Lord tested and liked much (on his TEC apo)
EYEPIECE, AXIAL DEF, EDGE DEF, ASTIG, LATCOL, GHOSTS, DEFOCUS, FIELD STOP
18mm Bertele, excellent, very good, none , none , none , slight°, sharp
°on his 1meter focal length refractor : null, none means not visible
Field stop is 15.5mm. Orthoscopic class (<10% distorsion), eye hole is 13.5mm diameter, eye lens center is 5mm recessed, eye relief around 9mm (4mm over the hole).
Given specs (microscopy) : focal length 14x in microscopy instruments that have 25cm fl <=> theorically 17,5mm with field geometric FOV 50,75°, FOV 52°, construction : 6 lenses / 4 groups (heavy index but classic glass), multi coated, russian AR treatement (a bit yellow centered like their binocular).
Real specs : converted to 1" 1/4 but no filter thread, AFOV appears ~60° (checked against TMB planetary) and shows to be more like a 15.5mm focal length (checked one to one image size vs RKE 15mm)
Not for eyeglasses wearer anyway.
A top, medium cost wide angle planetary ocular for refractor, fully corrected >85% field @f/6 (tested on a 80/480 apo), reach 100% @f/10 (Vixen 102M)
Proposed to 75$ / 61€ plus shipping cost.
- Condition new
- Location France