WANTED: CORONADO CaK 90

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piekielrl
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WANTED: CORONADO CaK 90

Post by piekielrl » Wed Dec 11, 2013 4:41 am

Does anybody here have a Coronado 90mm CaK scope they would consider selling? Not too many of them were made, and one by one, all of these are developing filter problems which seriously degrade the quality of the images. In talking to the engineers who designed them the culprit is the hygroscopic coatings in the filters themselves. They absorb moisture and degrade over time, and it seems like the time has come. This is apparently going to happen to all of them. I know of two confirmed cases of this and possibly a third. There is virtually no way to easily fix them today, as Meade/Coronado wants nothing more to do with CaK scopes, and no longer has the tooling or equipment to make new filters.
So don't ask me why I want one, but I want one DEAD OR ALIVE! Anyone want to part with one?
Thanks, Bob Piekiel

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solarchat
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Re: WANTED: CORONADO CaK 90

Post by solarchat » Wed Dec 11, 2013 5:40 am

I have two of the 6 known to exist that I use daily in outreach. Of course, I do not want to sell them but I am curious what. "Engineers that designed them " you talked to.
Stephen W. Ramsden
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Founder/Director Charlie Bates Solar Astronomy Project
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piekielrl
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Re: WANTED: CORONADO CaK 90

Post by piekielrl » Wed Dec 11, 2013 2:36 pm

The engineers who worked for Coronado and / or Lunt either as employees or consultants were Dick Buchroder, Bill Dean, Gene Cross, and a couple others who names escape me now (I am on a yahoo list serve with a team of about 50 of these optics guys), as this discussion came up a couple months ago. I have either directly contacted them or had a friend contact them on my behalf. I know you have two of them, you told me that in a private email. Greg P sold one a while back that had deteriorated , but he said it never worked as well as it should after recoating. Gary P has one now that has degraded. I am in contact with him regarding a purchase, but he's trying to get Bill Dean to re-manufacture filters for it before selling it, something that he says would cost at least $2000. I've spoken to the folks at Lunt about this. They won't touch a Coronado anymore, despite having worked on Greg's. I know of another guy who has a filter from one of these that he built into his own scope. Likewise, it is going bad. I have tried to get in touch with Brian Stephens about this, but so far have been unable. He sold his (serial #5) a couple years ago. As to "where the other scopes are?" I saw a web reference to one for sale at an astro shop in Portugal, but they never responded to my emails. Markus Ludes says he has none. Someone (perhaps you, Steve) told me that there's one in Europe (??) Who has these scopes now? Steve - you have two, Gary has one, where are the others??
Thanks, Bob

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Re: WANTED: CORONADO CaK 90

Post by solarchat » Wed Dec 11, 2013 4:33 pm

Well, I can tell you for certain that a Lunt B1200 or B1800 in even a mediocre refractor will outperform the Coronados. If that matters to ya.
Stephen W. Ramsden
Atlanta, GA USA
Founder/Director Charlie Bates Solar Astronomy Project
http://www.solarastronomy.org

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Re: WANTED: CORONADO CaK 90

Post by marktownley » Wed Dec 11, 2013 9:30 pm

A bit off the original thread here, but it's actually quite easy to get a CaK PST back to better than original condition by replacing the rusted elements that can happen in this scope - it is an ITF element similar to that found in a Ha blocking filter. I've never seen a 90mm coronado CaK in the flesh but i will bet money the filter train in it is the same as in the smaller CaK PST. Feel free to start another thread on this in the mods section if this is something you want you want to discuss further Bob :)
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piekielrl
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Re: WANTED: CORONADO CaK 90

Post by piekielrl » Wed Dec 11, 2013 9:45 pm

Thanks Mark, I actually have a Coronado CaK 70 that I love dearly. I bought it from Solar Chat Member Vince through his ad on astromart some time back. BTW, I like your video on disassembling a PST on youtube. I've dissected the PSTs, the SM60s, and the 70s before myself, now I'm struggling to get the threadlocker to release on my Coronado Ha SM90. "If it ain't broke, keep fixing it 'til it is..."
Thanks, Bob

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