Diagonal Question

[CanisMajorTom]

I have seen written on some spec sheets for Diagonals, the words "1/10 wave".

Does anyone know what this means?

[Astrolounge]

it referes to the flatness of the reflective face of the diagonal, 1/10th variation between the valleys and peaks and is usually said to have 99% reflectivity.

[Tenacious Del]

Interesting, I always thought this was because of the kind of reflective coatings they use.

[CanisMajorTom]

Cheers AL. :thumbsupmate:

[RSW]

To achieve 99% reflectivity, I imagine the glass also needs to be highly transparent. The technology in making glass these days is apparently quite sophisticated.

[CanisMajorTom]

I have been reading up on this (glass). I was surprised at how much goes into the engineering of optical glass.