Question regarding reflective coatings.

On 23 Jul 2003 20:39:17 GMT, (Chris1011) wrote:

Normally, coatings are applied
to glass substrates at high temperatures to give the surface molecules the
mobility to adhere to the incoming coating particles. New methods like ion
assist now allow this to be done at low temperatures. However, this does not
solve the problem of inter-layer strain. Baader has perfected a method of
applying the layers so that no strain is transmitted to the substrate. His
method makes possible an accurate small diagonal using these type of coatings.

Roland Christen

This is indeed good news. I've coveted your Maxbright, at least partly
because of it's robust coatings, but I've resisted buying one because
I know it would be the start down that slippery slope towards those
ultra-expensive 2" widefields.g

Here's hoping we'll soon see a Maxbright 1.25!

On another note, might Baader's new method eventually lead to
successful dielectric coatings on Newtonian diagonals and eventually
even primary mirrors?

Al Hall

Here's hoping we'll soon see a Maxbright 1.25!

On another note, might Baader's new method eventually lead to
successful dielectric coatings on Newtonian diagonals and eventually
even primary mirrors?

Unfortunately because the dollar has declined 25%, these smaller diagonals are
quite expensive. You can always use a 2" diagonal with 1.25" and even .965"
eyepieces. The diagonal will last forever, the eyepieces you will throw out
much sooner.

I'm not sure if he would make Newt diagonals. The process is more expensive
than is worth for a typical Newt. The cleanability is not that important for a
Newtonian where the light from each star or planet is spread out over a large
portion of the surface. In a star diagonal where the eyepiece is closer to the
diagonal surface, even small amounts of dust, dirt and crud have a very
negative effect on planetary contrast - thus the desireability of the cleanable
multi-layer dielectric coating.

Roland Christen

On 24 Jul 2003 22:19:46 GMT, (Chris1011) wrote:

The diagonal will last forever, the eyepieces you will throw out
much sooner.

I do like the idea of being able to clean the diagonal without
worrying about ruining it. My Lumicon needs cleaning right now and I'm
reluctant to do any more than blow some air over the surface of the
mirror. Unfortunately, the air won't dislodge the pollen grains.

Do eyepieces actually have a useful lifespan? I still have a couple of
UO Pro series orthos from the '70s that seem to be better than any of
my newer UOs at teasing the last bit of detail out on the planets. I
don't see myself throwing them out any time soon. How long do you
think a good eyepiece would last?

Al Hall