Quote:
Originally Posted by erick
Check you get astronomical binoculars (a green colour reflected from the objective (big) lens is the test).
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Quote:
Originally Posted by erick
Check you get astronomical binoculars (a green colour reflected from the objective (big) lens is the test).
Search "binoculars" on this site for lots of advice.
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Hi Eric,
The Green Coatings don't mean a lot per se. However, if you haven't used premium Japanese or German made binoculars its easy to form that opinion. The important issue with binoculars from an astronomy perspective is that the Binoculars use
"BAK4 prisms" and have
"fully multicoated" objective lenses. It just so happens by coincidence that 99% of the "Fully Multicoated Binoculars" coming out of China have "GREEN" coatings. A large number of the high quality binoculars which
are fully multicoated coming out of Germany and Japan don't have green coatings. Many of the high quality fully multicoatings have a deep purplish tone. They work very well for astronomy and are generally a quantum leap ahead of those coming out of China, notwithstanding the Chinese binoculars have "green" coatings.
The BAK 4 prisms ensure better transmission towards the edge of the Field of View than is possible with the cheaper BK7 prisms. It is easy to tell which prisms the binocular has. Hold them up to a light source and look at the exit pupil eminating from one of the binocular eyepieces. If the exit pupil is circular the prisms are BAK4, which is what you want. If the prisms are diamond shaped they are BK7 and I would avoid them.
Cheers,
John B