Takahashi Abbe MC Ortho 正交鏡

[peter]

Takahashi Abbe MC Ortho

https://www.cloudynights.com/topic/474675-the-takahashi-abbe-ortho-a-brief-summary/

正交鏡

https://www.astroshop.eu/eyepieces/15_10/a,Zubehoer.Allgemein.Bauart=orthoscopic


FOA : Fluorite Ortho Apochromatic
  FOA-60 from Takahashi is a new compact apochromatic fluorite doublet refractor.
  http://s00639.blogspot.com/2017/04/foa-60.html
 
==

TOA : Triplet Ortho Apochromatic   Ortho-Apochromat concept
  Triplet Ortho-Apochromat concept of the TOA refractors makes it possible to combine sharpness and extraordinary contras

==

Orthoscopic eyepieces have four lenses, of which two are biconvex curved and one biconcave. They offer a high degree of sharpness in the centre as well as at the edge. That's why they are interesting for observing planets and double stars. The advantage: they offer a flat field of view.

The low loss of light is another advantage of these eyepieces. The apparent field of view is approximately 40° – 45°.



OTHERS  正交偏光鏡
https://baike.baidu.hk/item/%E6%AD%A3%E4%BA%A4%E5%81%8F%E5%85%89%E9%8F%A1/6849545