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- To: "'Richard Baier'" <baierr@einstein.franklin.edu>, "atm-owner@shore.net" <atm-owner@shore.net>
- Subject: RE:
- From: Chris Westland <westland@uxmail.ust.hk>
- Date: Thu, 13 Feb 1997 09:11:12 +0800
Richard Baier [SMTP:baierr@einstein.franklin.edu] said On a different note, I have received a brochure from Obsession Telescopes. They claim that the Endurobrite coatings on their secondary mirrors, and I quote, "blows away ordinary enhanced coatings!". Is this claim legit or enhanced BS? [Chris Westland] The Obsessions have been using the Endurobrite coatings since 1991. These are dielectric coatings (alternative 1/4 wave layers of SiO and TiO2) ... the same coatings used to enhance the aluminium on enhanced coatings, but without the underlying aluminium (which is why it has to be groung off). They are great, and I think appropriate for a diagonal (QSP can do the primaries up to 40", but it is expensive). But "blows away ordinary enhanced coatings!" is really just Dave Krieges characteristic enthusiasm (he makes a great scope). You get another 3% of light transmission, which you should go for if it is not too expensive. But I would bet in a double blind test, no one could tell the difference between Endurobright and enhanced coatings, now that the yellow tinge has been eliminated. BTW QSP's owners started out doing Lumicons filters (OIII , UHC, etc.) and the Endurobright coatings are just an extension of this technology to make the opaque and sit right in the middle of the visible spectrum ... you can actually see through these mirrors, but the images look purple/red.
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