Re: [ATM] How dark is dark?

[Nils Olof Carlin <nilsolof.carlin@telia.com>]

Jack Galileo,

>>>Suppose you had a priceless OTA that Galileo himself built and only 
one chance to paint it. The interior is very rough (since the wood of 
this priceless OTA is made from Swedish engineered birch flooring and 
the backside is rough cut). Would you have enough faith in the evidence 
to paint
it glossy?

With such a remarkable, priceless anachronism, I wouldn't even 
consider using it for observing, much less painting it.

I personally prefer low-price instruments that I make myself - and 
designing a new (or more likely an old) one, there are many other 
things I would plan before even considering the kind of paint to use. 
Some of the things I would consider are mentioned here:

http://web.telia.com/~u41105032/stroljus/stroljus.htm

(For copyright reasons only in Swedish, but you may see the book 
mentioned in the ingress for the article in English!)

One thing I would consider is making the tube large enough not to need 
any baffling at all! This is entirely practical, but it does not solve 
the problems of the upper tube assembly, i.e. the light that may enter 
the EP from areas outside the secondary. I would still need to blacken 
the area around the primary visible via the secondary, but before I do 
that I would follow Galileo's example of actually finding out how 
things work instead of the scholastic way of finding the solution by 
protracted discussion. One thing I'd try is black velvet.

In conclusion, I'd give much more consideration to the geometry of the 
telescope tube than the paint to use. 

Nils Olof
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