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Any scope spectrometer ratings on WEB

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/04/2005 at 23:27
Superlite17 View Drop Down
Optics GrassHopper
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Joined: July/25/2005
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Was wondering if you guys knew of any real 3rd party light spectrometer ratings comparing different scopes??? I cannot find any real scope ratings  on the web, all seem biased... by their advertisers!

 

Thought i would see if you guys had found anything that i could not!

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/07/2005 at 14:26
noddah View Drop Down
Optics Apprentice
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Problem is all the tests (I have seen) are with the glass that makes up the telescopes, scopes, cameas, scanners, etc...

 

This is why sometimes you will see a transfer of light figure described by each glass surface. 

 

In the scanner industry they test all these topics in optics... focus, sensitivity of sensors and sweet spots..

 

such as here: www.scannerforum.com

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/10/2005 at 09:58
Dale Clifford View Drop Down
Optics Jedi Knight
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Which spectrum are you going to sweep? Visible light only, ok, does knowing that the combination of glass you are using absorb in the lower reds change anything. ok it gives outstand image against certain backrounds but seems to be muddy in broad daylight but not as "clear" (what ever that means). Ok lets scan in the uv and higher to see if invisible part of the spectrum is causing to much heat build up and expansion. Or are you looking for higher transmission across all visible. If that scope has a 3 glass elements and the transmission in each is 98% that is not 98% but only 94% for the group. Is that better than a 4 glass element with a total of 95%?  but  Now for the hard part, lets all get together and decide on what specs mean something to make comparisons mean something. Will the fact that some cheap scope made to looser tolerances having better figures because for some reason the errors cancel out tell you anything? And what about the problem of eye problems. Would a person with a radial asigmatism "see" a scope with excellent figures as their best buy? The eyes retinal adaptation mechanism is sensitive over a log base of 10 orders of magnitude. (a match in the dark to looking directly into the sun). No machine even comes close. This says nothing of the fact that you don't see light but photons, and you really don't see these but only the chemical and electrical by-products which have different ratios in each person. Colors are selected by elimination (you can't tell me what color green is, only that it is not blue or yellow) whereas a machine can tell you because of the wavelength. Ok now that we have all these spectrophotometric readings and images readjusted by digital enchancement and wavelet edge compression eliminating the Gibbs problem, can someone tell me how to make the scope stop moving so I can hit the target.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/11/2005 at 11:45
noddah View Drop Down
Optics Apprentice
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Make it stop!        

 

According to the above the best way to test complete scopes would be:

 

To make a P.M.T. (Photo Multiplier Tube) Machine which would:

 

1. Calibrate the voltage to a fiber optic lamp without the scope as a baseline.

2. Clamp the scope into the machine. (We would probably want the scope with out a reticle and have it set to the lowest magnification and focus would be an issue betweeen type)

3. Take a new reading from the light and compare the spectrum before and after readings.

 

Reading would have to be done in a dark enviroment.. of course.

 

PMT Scanners today are based on three RGB Photon Sensitive Tubes which are able to read ISO Status A Density from .01 White to 3.9 Black and can be calibrated to an accuracy of .004 between readings. PMT's are also approximately 60% more senstive than the human eye.

 

So the real question...do you think the industry would want to buy such a machine? 

 

 

 

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/12/2005 at 09:02
Dale Clifford View Drop Down
Optics Jedi Knight
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Making rifle scopes is not rocket science. The sweet spot (index) you describe is combination of a physical parameter and a mathematical convolution called a LTF (a linear transfer function). Some makers two I know of Leo and Zeiss use this variations of this technique to match pieces of glass going in the same tube. All gain devices, receivers are more sensitive at one frequency or wavelength, but not accross a spectrum. Critical application devices, biological microscopes, and other high dollar devices allow this additional cost to be added in. No -for scopes the meter reader would cause more advertising problems than benefits.
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