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  #1  
Old 15-11-2017, 11:30 AM
jimmyh1555 (James)
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Location: George Town TAS
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When do I need a new mirror

I have a beautiful 12 inch Lightbridge. It is about 12 years old, and the mirror looks horrible. It has pock marks all over the surface which won't clean off, and in a few small places, the silvering has come off.
BUT.....last night I was looking at Orion M42 and the LMC, and the view through the eyepiece looked great - plenty of nebulosity and in the LMC, lots of star clusters - though these appeared rather faint.
How much deterioration should I put up with before either replacing or repairing the mirror Can i get it resilvered, or a new one for $600? What do you guys out there recommend? I would love to hear your comments
Jimmy
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  #2  
Old 15-11-2017, 11:38 AM
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multiweb (Marc)
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If it's a good figured mirror to start with then recoating it would be the best option. If the damage is too deep and affected the glass surface then depending how big a surface it is buying a new one would be best. You'd have to get the same FL or you'll have to modify your tube length or focuser placement.
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  #3  
Old 15-11-2017, 12:43 PM
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bojan
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Location: Mt Waverley, VIC
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Interesting.. I still have 10" f/5.6 Coulter Optical mirror that I bought it in USA back in '80-ies.. and it is still OK, after 5~6 washing and an accident (when the tube slipped out of my hands and hit the concrete pavement, resulting in secondary hit the primary and damaged the coating.. if not for that, it would have been perfect), even after so many years.
Even like it is now, it is quite good (IMO).
Looks like they do not do things like they used to in the good old days...
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  #4  
Old 16-11-2017, 09:27 PM
jimmyh1555 (James)
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any info regarding recoaters in Aussie? There must be somebody who does it!
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  #5  
Old 18-11-2017, 10:42 AM
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multiweb (Marc)
ze frogginator

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Quote:
Originally Posted by jimmyh1555 View Post
any info regarding recoaters in Aussie? There must be somebody who does it!
http://www.iceinspace.com.au/forum/s...ad.php?t=92288
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  #6  
Old 18-11-2017, 11:05 AM
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Zubenel (Wes)
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Give Waye at Saintech a call. SDM Telescopes use him !!!
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  #7  
Old 25-11-2017, 02:14 PM
PhilTas (Phil)
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Location: Darwin
Posts: 105
I’ve also got a 12” dob (Bintel/GSO) with a very dirty mirror. The previous owner had kept it in a shipping container. The top end heat and humidity has not been kind to it.
I’ve washed it twice, and apart from clearing a layer of dust and dirt, it is still in a bit of a sorry state.
But, I have enjoyed some very nice views through this scope.
The purists here will say that we shouldn’t accept second rate views, but I think that we only lose a little bit of contrast when the mirror is less than perfect. For visual use, I am very happy with it.
Jimmy, if you know anyone with a similar size scope, try to arrange a comparison. You might be surprised at how similar the views will be.
Cheers Phil
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