Re: ATM "Un-scratching" a mirror?

["Dan Chaffee" <dchaffee@gvi.net>]

> coated.  The question on this one is:  is there a simple way to strip the
> aluminum without digging into the glass?  It looks like most (all??) of
> the scratches didn't go past the aluminum layer,  and I might be able to
> get away with just recoating. 

Try ferric chloride for etching printed circuit boards-sold at Radio
Shack here in the States.
> 
> The other one looks more promising:  about half-a-dozen very fine 
> scratches in random locations.  The "optics for newbies"-level books say
> that,  in theory,  all I have to do is blacken the scratches,  and
> everything will be hunky-dory,  with just a loss of the .1% or so of light
> grasp where the surface is covered.

I would'nt do anything like that; the painted marks covering the scratches
will cause far more diffraction/scattered light than the scratches
themselves
could. A few scratches will not damage images at the eyepiece, in fact a 
considerable number will produce a signal to noise ratio well within an
acceptable level. As far as light loss is concerned, it would take a 
truely astonishing number of them to yield .1% loss.  When it comes to 
fixing tiny flaws, as an art conservator friend of mine says, "better
is often the enemy of good".

D Chaffee