doctor 12.5mm eps

i have read these eps are from binos, does anyone know
what model? nowadays they are used in the aspectum
series 40x80, but they must have been in previous,
thanks for any info, bob

I believe that these eyepieces were being sold for use as individual eyepieces before they were being offered as an option with the Aspectum binoculars. They are still available today as single eyepieces and I think APM Telescopes in Germany sells them. I also believe that these eyepieces are available as an option for use with the 60mm Doctor Aspectum spotting scope.

I tried a pair of 40 x 80 Aspectum binoculars with these eyepieces in them last Spring and I was dissappointed with them. They have a short 10mm of eye relief and when you bring the two barrels close enough together to form a single image the resulting (visible) field of view appears to be about 65 to 70 degrees (apparent field) at most. Yes, when looked through individually they do appear to have an 85 - 90 degree apparent field (if you put you eye up close, tilt your head, and look off to the side), but when used in binoculars they don't deliver (in a usable form) anything like a 90 degree apparent field. That in turns results in their true field being more like 1.75 degrees rather than the 2.25 degrees that it would be if you could actually use it.

If you are interested in an Aspectum binocular I suggest that you try their 30 x 80 model instead. It has much better eye relief, is easier to observe with, and it costs a few hundred dollars less. Also, do to its longer eye relief and lower magnification it is easier to keep them reasonably steady (when used on a mount) than it is with the 40 x 80 model.

For single eyepiece use I'd rather have a 12mm Type 4 Nagler or a 13mm Type 6 than the 12.5mm Doctor (former Zeiss Jena) eyepiece. However, the 12.5mm Doctor eyepiece is a nice wide field eyepiece for stand alone use.