Re: ATM Painting sides of mirror...

[Anthony Stillman <atmer@flash.net>]

>...paint the side...?  Will it matter?
>...how about the beveled edge...of the primary?
>..."Caution: contains Xylene."



Pete,

The issue of emissivity with regards to the sides and back of mirrors and
its relationship to figure has been previously discussed on the list.  As I
recall there was no agreement and no one did or referenced any studies.
Personally I don't think its a good idea to unduely raise the emmissivity
of the sides or back of an optic.  Clearly if the substraite is
equilibrated it makes no difference.  As the temeperature varies with time,
the optic is of course never equilibrated.  Hence if the the heat loss
through the sides exceeds that through the face/s I would expect greater
thermally induced distortion.  So my answer to your question is no, don't
paint them.

As for the mirror bevel.  Blackening the bevel will increase contrast by
reducing scattered light.  The best way I know to do this is to center the
mirror on an old phonograph (they are kind of like CD's but bigger) and
then use a Sharpie and a steady hand.  This also works to decoratively
detail an turned edge.

Xylene is a know carcinogen to the State of California.  Of course air is a
know carcinogen IN the State of California.

Anthony