|
Hi Allen,
I recently asked this group the same question and got the following response from gp_astro:
Just contacted Wayne to clarify the differences between his two Al coating techniques.
Looks like my previous description of Wayne's process was out of date or just wrong.
So:
Both use his low pressure ion assisted deposition method.
Both apply a 200nm aluminium layer.
The Aluminium + Quartz applies a 200nm layer of SiO2 as the overcoat.
The Aluminium Enhanced applies multiply layers of Titanium and Tantalum Oxides as the overcoat to a thickness of 15O nm.
Wayne says the enhanced coating is harder than the quartz coating although it is thiner of course.
As to which overcoat would protect the mirror better is a tough call.
Thiner/harder verses thicker/ softer.
Probably turn out to be the same.
gb.
From what I can gather the difference in price used to be much greater so the choice wasn't so easy. I have also read many opinions on the web that recommend not getting enhanced so who knows. I went with enhanced but then Wayne found blemishes on my mirror so he sent it back uncoated until I decide what to do.
Mark
|
