Re: Magnesium Flouride

[Bernard Cleyet <anngeorg@PACBELL.NET>]

The amount of improvement in multi-air-spaced lenses is considerable,
However for a single lens e.g. telescope objective or corrector plate, I
think it's a waste of money.  Where they get 20% beats me.  Since the
field is rather narrow, I'd expect it to be 4% at each surface.  Where
the impedance matching (anti-reflection) is very important is the
reduction in flare.  Again most important in multi-lens systems.

http://www.meade.com/catalog/uhtc/


I suppose reading the above carefully will explain.  It does mention
four surfaces -- I think they're including reflection coating on the two
mirror surfaces in addition to the corrector plate?

I wonder if spending the xtra $300 * on a better ccd or better oculars
would be more "cost effective"?

* This is for the improvement over the std. coating?   Of course, if one
is using the 'scope for research where flat transmission is important,
it may be worth it?

bc, who has a Celestron, claimed to include UHTC coatings for no xtra cost.


Bob Sciamanda wrote:

> Addendum:
> I neglected to directly address David's concern:
> Both film and solid state cameras will profit from anti-reflection coated
> lenses, so that they might make exposures under weaker light conditions
> and/or using less exposure time.
>
> Bob Sciamanda
> Physics, Edinboro Univ of PA (Em)
> http://www.velocity.net/~trebor/
> trebor@velocity.net
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