#1  
Old 15-11-2017, 11:30 AM
jimmyh1555 (James)
jimmyh1555

jimmyh1555 is offline
 
Join Date: Jun 2017
Location: George Town TAS
Posts: 156
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
Reply With Quote
  #2  
Old 15-11-2017, 11:38 AM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
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.
Reply With Quote
  #3  
Old 15-11-2017, 12:43 PM
bojan's Avatar
bojan
amateur

bojan is offline
 
Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,932
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...
Reply With Quote
  #4  
Old 16-11-2017, 09:27 PM
jimmyh1555 (James)
jimmyh1555

jimmyh1555 is offline
 
Join Date: Jun 2017
Location: George Town TAS
Posts: 156
any info regarding recoaters in Aussie? There must be somebody who does it!
Reply With Quote
  #5  
Old 18-11-2017, 10:42 AM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
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
Reply With Quote
  #6  
Old 18-11-2017, 11:05 AM
Zubenel's Avatar
Zubenel (Wes)
Awe and Wonder

Zubenel is offline
 
Join Date: Aug 2005
Location: SE QLD
Posts: 585
Give Waye at Saintech a call. SDM Telescopes use him !!!
Reply With Quote
  #7  
Old 25-11-2017, 02:14 PM
PhilTas (Phil)
Registered User

PhilTas is offline
 
Join Date: Apr 2013
Location: Darwin
Posts: 189
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
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 02:28 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Testar
Advertisement
Bintel
Advertisement