What's new
New posts
New media
New media comments
New profile posts
New review items
Latest activity
Forums
New posts
Search forums
Gallery
New media
New comments
Search media
Reviews
New items
Latest content
Latest reviews
Latest questions
Brands
Search reviews
Opus
Birds & Bird Song
Locations
Resources
Contribute
Recent changes
Blogs
Members
Current visitors
New profile posts
Search profile posts
ZEISS
ZEISS Nature Observation
The Most Important Optical Parameters
Innovative Technologies
Conservation Projects
Log in
Register
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
BirdForum is the net's largest birding community dedicated to wild birds and birding, and is
absolutely FREE
!
Register for an account
to take part in lively discussions in the forum, post your pictures in the gallery and more.
Forums
Binoculars & Spotting Scopes
Binoculars
7x35 Aculons, Featherweights, and 7x35 Porros in General
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="Binastro" data-source="post: 3366755" data-attributes="member: 111403"><p>Gemstones allowed finer detail to seen, actually useful.</p><p>Numerical aperture.</p><p>Spherometer measures curves on optics.</p><p></p><p>I have not found thorium in binoculars, mainly in lenses 1940 to 1978.</p><p>Some WW2 elbow scope eyepieces etc.</p><p>Thorium in Kodak WW2 eyepieces and some 4mm Swift and unnamed 6mm Japanese eyepieces. Orthoscopics.</p><p>Alpha, beta and Gamma.</p><p>Also Uranium glass filters WW2, and later camera lenses not necessarily thorium.</p><p></p><p>Aculons 90%. I very much doubt it. If the prisms aren't coated immediately 8% off.</p><p>How many reflections from a single lightbulb are white, how many coloured?</p><p></p><p>P.S.</p><p>Some 100mm and 120mm camera lenses are radioactive.</p><p>Kodak 24inch f/6 for 18x9 inch film, highest reading I got. Detectable at 6ft. Rear element.</p></blockquote><p></p>
[QUOTE="Binastro, post: 3366755, member: 111403"] Gemstones allowed finer detail to seen, actually useful. Numerical aperture. Spherometer measures curves on optics. I have not found thorium in binoculars, mainly in lenses 1940 to 1978. Some WW2 elbow scope eyepieces etc. Thorium in Kodak WW2 eyepieces and some 4mm Swift and unnamed 6mm Japanese eyepieces. Orthoscopics. Alpha, beta and Gamma. Also Uranium glass filters WW2, and later camera lenses not necessarily thorium. Aculons 90%. I very much doubt it. If the prisms aren't coated immediately 8% off. How many reflections from a single lightbulb are white, how many coloured? P.S. Some 100mm and 120mm camera lenses are radioactive. Kodak 24inch f/6 for 18x9 inch film, highest reading I got. Detectable at 6ft. Rear element. [/QUOTE]
Insert quotes...
Verification
Post reply
Forums
Binoculars & Spotting Scopes
Binoculars
7x35 Aculons, Featherweights, and 7x35 Porros in General
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more...
Top
