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Date: 18 Oct 2006 01:49:29
From: Jim Wilkerson
Subject: Mirror Recoating
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As my scope is close to 10 years old now, I am considering sending the
mirrors in for re-coating.
Over the years I have heard that Clausing is pretty good, especially
their Beral coating. Now I see that they also offer a coating called
Diamond -Brite.
My questions:
How much more expensive is the Diamond-Brite coating? The Beral is
91% reflective and the D-B is specd' at 97%. Is the difference worth
it (I realize that this q is probably in the Eye of the beholder....).
Or, are there better mirror re-coaters out there that I should
consider?
This is a 10" mirror with the corresponding secondary that I am
looking to get re-done.
Thanks so much.
Jim
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Date: 18 Oct 2006 23:35:41
From: Jax
Subject: Re: Mirror Recoating
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Our observatory uses Spectrum and so have I with very good results. Prices
are on their web site.
http://www.spectrum-coatings.com/mirror.htm
peace,
jon II
"Jim Wilkerson" <wilkerj@attglobal.net > wrote in message
news:RFFxzJm83E64-pn2-NuiOnYp3m8Hj@localhost...
> As my scope is close to 10 years old now, I am considering sending the
> mirrors in for re-coating.
>
> Over the years I have heard that Clausing is pretty good, especially
> their Beral coating. Now I see that they also offer a coating called
> Diamond -Brite.
>
> My questions:
>
> How much more expensive is the Diamond-Brite coating? The Beral is
> 91% reflective and the D-B is specd' at 97%. Is the difference worth
> it (I realize that this q is probably in the Eye of the beholder....).
>
> Or, are there better mirror re-coaters out there that I should
> consider?
>
> This is a 10" mirror with the corresponding secondary that I am
> looking to get re-done.
>
> Thanks so much.
>
> Jim
> --
>
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Date: 18 Oct 2006 17:53:06
From: Paul Winalski
Subject: Re: Mirror Recoating
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On Wed, 18 2006 01:49:29 GMT, "Jim Wilkerson"
<wilkerj@attglobal.net > wrote:
>As my scope is close to 10 years old now, I am considering sending the
>mirrors in for re-coating.
>
>Over the years I have heard that Clausing is pretty good, especially
>their Beral coating. Now I see that they also offer a coating called
>Diamond -Brite.
>
>My questions:
>
>How much more expensive is the Diamond-Brite coating? The Beral is
>91% reflective and the D-B is specd' at 97%. Is the difference worth
>it (I realize that this q is probably in the Eye of the beholder....).
>
>Or, are there better mirror re-coaters out there that I should
>consider?
>
>This is a 10" mirror with the corresponding secondary that I am
>looking to get re-done.
>
>Thanks so much.
Diamond-Brite is one of the high reflectivity (97%, in this case)
coatings. The advice I've always seen from experts is that this sort
of coating is not recommended for primary mirrors. Beral, on the
other hand, is 91% reflectivity. I see also on Clausing's web page
that "astronomical mirrors" is listed as a typical use for Beral, but
not for Diamond-Brite. On the other hand, high reflectivity coatings
*are* recommended for secondary mirrors, so I would consider going
with Beral coating for the primary and Diamond-Brite for the
secondary.
As for the price, I suggest visiting the H. L. Clausing web site, then
sending them email asking for a quote for your job.
My 14" mirror has a Clausing Beral coating and I'm very happy with it.
Great views, and no problems so far (I'm in the 3rd year since the
coating).
Clear skies,
-Paul W.
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Date: 19 Oct 2006 13:16:23
From: Dennis Woos
Subject: Re: Mirror Recoating
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"Jim Wilkerson" <wilkerj@attglobal.net > wrote in message
news:RFFxzJm83E64-pn2-NuiOnYp3m8Hj@localhost...
> As my scope is close to 10 years old now, I am considering sending the
> mirrors in for re-coating.
>
> Over the years I have heard that Clausing is pretty good, especially
> their Beral coating. Now I see that they also offer a coating called
> Diamond -Brite.
>
> My questions:
>
> How much more expensive is the Diamond-Brite coating? The Beral is
> 91% reflective and the D-B is specd' at 97%. Is the difference worth
> it (I realize that this q is probably in the Eye of the beholder....).
>
> Or, are there better mirror re-coaters out there that I should
> consider?
>
> This is a 10" mirror with the corresponding secondary that I am
> looking to get re-done.
>
> Thanks so much.
>
> Jim
> --
>
Everybody has their favorites, less or least favorites, and there are some
horror stories floating around. I have to say that I have never heard
anything bad about Spectrum, and a couple of guys in our club swear by
Clausing (Beral). I have always been anxious about shipping a mirror
(though I have never had any problem) and I would probably use a coater I
could drive to for drop-off and pick-up.
Dennis
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