Re: ATM Protecting coated mirror.

[Andrew Grisdale <roadwarrior@techieguy.com>]

Thanks Jim,

> Hate to say this, but chances are heavily weighted to your have a very
> horrible result.  Decent scopes have, at the very worst, an accuracy of 1/4
> wave of visible light.  That is probably 10 to 100 times (or more) the
> accuracy of the materials you are talking about.  This will mean very low
> power and distortion.
I will be satisfied with a recognisable image of the moon, and terrestrial viewing with 
this mirror, I aimed it at a clanedar across the room and found the image in a 30mm 
eyepiece and was pleasantly suprised that I could read the calendar and that the squares 
on it were square still!

> >My first thought was to use candle wax, but I don't know how much trouble
> >I would have in removing it, I was thinking to heat off some, then wash
> >with kerosene (parafin) then rinse,
> 
> I can't think of anything you could apply by hand that would not be hugely
> thicker than any kind of commercial coating, as relates to the wavelengths
> of light you will be dealing with.  This, again, would introduce
> distortions invisible to the naked eye, but catastrophic when attempting to
> revolve pinpoints of light.  The images would be heavily diffracted.

Hmmmm? Sorry I meant I need a coating to protect it while cutting an elliptic out of a 
trapezoidal mirror I pulled out of the camera. It's a first surface mirror and came out 
of a camera, should be near optical quality, so I think I will get better performance out 
of this than the primary, I take your point about how horrible it all might be thou
gh.

> 
> Xylol or Xylene from your hardware store will slowly disolve wax.
Is that anything like laquer thinner?

> I know where you can buy a kit for building an entire 3" newt minus
> eyepiece for $39.50.
oooh, that sounds good, not sure if 3" would be a worthwhile step up from my 60mm 
refractor though, anything bigger for same value?

thank you again, steady hands and steady skies!

Andrew G.


_______________________________________________________
Are you a Techie? Get Your Free Tech Email Address Now!
Many to choose from! Visit http://www.TechEmail.com