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Mirror longevity.

Smithfire

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clarkpm4242

clarkpm4242

Posted
Posted

Hi guys

Do mirrors fair better if kept in the house? I cleaned my mirror a few months back and it is starting to go milky already. I keep it in a dry shed outside.

Many thanks

Clive

Hi

The temperature inside the 'dry' shed will cycle, day through night and with seasons.  This can cause repeated condensation on the mirror...

...as Peter D. noted, 7 - 10 years is a reasonable lifespan for a coating.

Cheers

Paul

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ronin

ronin

Posted
Posted

I suspect that you are just at the end of it's pristine life.

Seem to recall that 8 years was fair and 10 years good, and has been said a lot depends on how good the coatings, aluminium and protective, started out.

Moisure, condensation etc also tends to be slightly acidic, which does no good to the coatings.

Not sure who recoats mirrors if you decided to head down that avenue.

Galvoptics do or did - they altered their website and assorted things have disappeared.

There is Orion that might and Oldham Optics also, not 100% sure on the services provided.

There used to be someone in N London, top edge of M25 ?, that I think did mirrors but they have either disappeared or become quiet.

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Mr Fiery Jack

Mr Fiery Jack

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Some manufacturers claim remarkable life spans for their mirror coatings, Orion Optics HiLux as an example. Predictions of mirror longevity of 25 years or so are in my experience somewhat over optimistic. I had a several large holes in an extremely well looked after 10 inch Europa that was 8 years old.

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John

John

Posted
Posted

Some manufacturers claim remarkable life spans for their mirror coatings, Orion Optics HiLux as an example. Predictions of mirror longevity of 25 years or so are in my experience somewhat over optimistic. I had a several large holes in an extremely well looked after 10 inch Europa that was 8 years old.

I'm not sure that Europa's had Hilux coatings, as standard, 8 years ago ?

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NGC 1502

NGC 1502

Posted
Posted

I suspect that you are just at the end of it's pristine life.

Seem to recall that 8 years was fair and 10 years good, and has been said a lot depends on how good the coatings, aluminium and protective, started out.

 

Moisure, condensation etc also tends to be slightly acidic, which does no good to the coatings.

 

Not sure who recoats mirrors if you decided to head down that avenue.

Galvoptics do or did - they altered their website and assorted things have disappeared.

There is Orion that might and Oldham Optics also, not 100% sure on the services provided.

There used to be someone in N London, top edge of M25 ?, that I think did mirrors but they have either disappeared or become quiet.

 

Galvoptics are just 10 miles from me, I've had mirrors recoated there and so have several members of my local club.

http://www.galvoptics.co.uk/products/telescope-products-andamp-services/telescope-mirror-coating---primary/

Also Orion Optics and I think Vacuum Coatings recoat mirrors.

Regards, Ed.

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scarp15

scarp15

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I certainly keep mine indoors in our back room and feel grateful that they have an accepted allocated space to occupy in a family home. Reassuring that the scopes are kept in a dry, clean environment free from condensation. Not so reassuring that they are at least indoors 99.5% of the time currently.

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Dave In Vermont

Dave In Vermont

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I got an Orion-USA 200mm F/4 Newt back in 2000. It was manufactured by GSO, and Orion was selling them way to cheap by mistake. So they were quite rare as Orion pulled them off the market quite quickly - once they realized their error. So I was one of the lucky few. The optics were, and are, superb. But they needed a re-coating last year. The mirror was losing it's shiny-bright nature. So that was 14 years. It was stored indoors in a warm environment.

The re-coating truly brought it back to it's original quality. If you're in the US and need a re-coat for yours, I used Majestic in New Jersey, which I do recommend. Total cost, with shipping, was $115.00.

Enjoy!

Dave

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Smithfire

Smithfire

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Thanks Dave.....not in the US but darkest rural Oxfordshire, England.

I guess if i do have the mirrors recoated, then I'll have to think of a better way to store it.

Maybe if I remove the dust cover while the temperature stabilises it will let any condensation escape?

Clive

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