EVOSTAR DS-PRO Series ED refractors

[starscy]

I was told that the new Sky-Watcher Evostar DS-PRO Series ED refractors use Schott glass and are optically (and mechanically) superior to previous Evostar ED refractors. Specifically I was told that an Evostar 80DS-PRO could perform better than an Evostar-100ED. Is this accurate? How would a Celestron C100ED-R compare to an Evostar 80DS-PRO?

[FLO]

I was told that the new Sky-Watcher Evostar DS-PRO Series ED refractors use Schott glass

Yes, that is true. Around March this year Skywatcher announced that they had won an exclusive co-branding agreement with Schott, the German glass manufacturer.

... and are optically (and mechanically) superior to previous Evostar ED refractors.

Mechanically: The ED DS PRO series are supplied with dual-speed (hence the 'DS') focusers whereas the regular ED PRO had single-speed, otherwise they are the same.

Optically: Schott glass is excellent and it is easy to see why Skywatcher are so pleased to have the exclusive co-branding agreement. But, we don't know how long they were using Schott glass prior to their announcement, and Schott glass is not the only premium glass manufacturer (Skywatcher still use Ohara FPL-53 glass for the ED element) so it is difficult to say absolutely that the optics have improved.

Specifically I was told that an Evostar 80DS-PRO could perform better than an Evostar-100ED. Is this accurate?

No, that is almost certainly not true. The 100ED has a longer f-ratio and a larger aperture, that will have a greater influence than any possible gain from using Schott glass for the crown element. The 100ED should have greater correction of false colour and greater resolution. (aperture doesn't only affect light gathering, it also determines maximum resolution, it is an optical physics thing).

How would a Celestron C100ED-R compare to an Evostar 80DS-PRO?

See last comment.

HTH