Re: [ATM] How dark is dark?

["Vladimir Galogaza" <vladimir.galogaza1@zg.t-com.hr>]

Jerry,

>I suggest another experiment. Take two flat boards or pieces of cardboard
>the same size. Paint one with flat black, Paint the other with glossy 
>black.
>Place the two boards in the center of the room and turn on the lights.
>Which board shows greater reflections of the lights and objects in the 
>room?

Jeff in his post answered what is to be expected in such an experiment.
Though the proposed experiment does not address the problem.

Original problem was what kind of surface finish is better in telescope?

It is clear that "better" means better in minimizing amount of stray light 
in the eyepiece.
Surface absorptivity & reflectivity are only some of factors playing the 
role.
Ideally if surface will be perfect reflector but all reflected light could 
be directed away from the eyepiece the goal is achieved. 
Whether this is done by clever design of baffles (macro ) or by
surface nature and texture (micro)  or any combination
of this is like skinning the cat.
And as Ken said:
> Now the question becomes, "Do any of us have good enough
>eyes that we will be able to see the difference?".
in residual light providing  reasonable measures were taken.


Regards
Vladimir.




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