New coatings for mirrors....

[Merlin66]

https://www.sciencedaily.com/releases/2017/09/170918222301.htm

Silvered mirrors plus overcoat....

[Kunama]

They're just doing what Baader BBHS is but on a larger scale :P

[lazjen]

It would be nice to know how much of a difference it would make, but it sounds good.

[Wavytone]

Interesting. If you have a really good scope you plan to keep for many years, it would be worth having this done.

On a single mirror (newtonian primary) you could increase transmission 30% over an old aluminium coating. Older 2-mirror scopes - SCT's and Maks - where the coatings last quite well but nevertheless do slowly oxidise with age and after 10 years may may have transmission below 50% - this would restore them to better than new which would be a very noticeable improvement and presumably cheaper than a new OTA.

If it becomes reasonably available here I'd definitely have my Santel Mak done.

On a smallish mirror (star diagonals) with 99% dielectric coating forget it - there isn't any significant improvement to be had.

[rustigsmed]

+1