Something's still wrong here. There's only one mirror surface in the pair of prisms, and if it's silver it's not dielectric. The word "dielectric" is apparently also used for other coatings, like phase correction, which the other (roof) prism would indeed have. So if we're talking about the mirror, this answer is still "silver not dielectric". And I'm beginning to suspect that the answer Gijs got is the same.
Apparently. Gijs asked specifically if the roof prism was dielectric coated and was told it was. I had previously been told by Meopta that the prism was silver mirrored so I asked for clarification on the coatings. This was the reply "The roof prisms are coated with dielectric coatings, nevertheless the prism system includes also half-penta prism which has silver coating."
Anyone who has tried the current generation of Meostars will know that they definitely do not have the yellowish cast of the older models. They are now close to neutral, and to my eyes have a better colour presentation than the current Swaro and Zeiss offerings.
Unfortunately I was asked not to post the transmission spectra I was sent when I reviewed the 12x50HD, but was told I could describe it. The trace hovers around the 90% mark between 500nm and 675nm with perhaps a 2 or 3% high point in the red. At the blue end of the spectrum the trasmission is still 80% at 430nm (what used to be called indigo) and 60% at 400nm in the violet. At the other end of the spectrum in the deeper red, it's still 80% at 700nm and 55% at 780nm. In my book, that is very good..
David