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Re: Corrosion in Hawaii


 

Well, my scope is a truss style Newtonian, all open. Your approach would mean building a whole new airtight N2 sealed telescope... or at least optically sealing the primary mirror. Due to cost and weight issues, probably not on my "to do" list anytime soon!

The vog and SO2 in Hawaii has increased dramatically since the 2008 Halemaumau eruption. Most of the time during normal trade wind weather the vog will collect over the whole Kona side of the big island, so thick that it reduces visibility to like the worst smog days in LA. The vog tends to dissipate and diffuse away towards Waikoloa and the northern parts of the island, and is concentrated in streams as it passes by the southern end of the island, so these areas have highly variable vog conditions.

I suspect my coating issues are primarily caused by infrequent but intense vog episodes, where a highly concentrated cloud or stream passes right over my location. Most of the time the vog is very light and I do not believe it would cause the problems I am experiencing on a regular basis, since I am usually in the NE trade wind flow blowing the corrosives beyond me to Kona.

I do try to keep my mirror tightly covered with a close fitting metal cover when not in use. This may avoid the problems I have experienced before with these occasional vog clouds. Time will tell.

Mike

--- In VacuumX@..., Russ Thornton <rocky_beech@...> wrote:

Just a thought. I have not heard this discussed before here or maybe I just
missed it. I know that you guys want just the purest optics possible so this
idea may make you gag but I work at Cape Canaveral and they have
some pretty impressive optics there. I believe that some of their solutions to
the corrosion are to mount a flat glass over the opening and understanding that
the rest of the tube is sealed flood the chamber with nitrogen or some other
inert cheap gas. Is that a workable solution for you?
Russell

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