When should you recoat a telescope mirror?
All telescopes have to recoat their mirrors every few years. Most telescopes coat their mirrors with a very thin layer of aluminum. The exceptions are the Gemini Telescopes, which recently coated their mirrors with silver.
How long do telescope coatings last?
With regular use the older coatings typically last about 10 years, while the newer enhanced coatings may last more like 20. But there are many variables that come into play.
Do telescope mirrors use silver?
According to Phillips, most astronomical telescope mirrors use aluminum for the reflective layer, despite the superior reflective properties of silver. “You need barrier layers on top that can keep anything from getting through to the silver without messing up the optical characteristics of the mirror.”
Can mirrors be recoated?
One of the most important and very widely used services we offer is the re-coating of established or, coating of newly made mirrors. …
Do telescopes wear out?
Unlike so many products in our throwaway society, where built-in obsolescence seems the rule, telescopes often outlast their owners. They require little care and attention and cost nothing to keep. With a little common sense on your part, a telescope will return a lifetime of fascination.
What is the silver backing on a mirror?
What is Silvering? Silvering is a chemical process of coating a non-conductive substrate like glass with a reflective substance, to produce a mirror. “Back silvered” or “second-surface” is the standard way household mirrors were produced, meaning the light reaches the reflective layer after passing through the glass.
Which metal coating is used in the mirror?
The most common metals used are copper and aluminum. Although beryllium is highly toxic, it is used when especially light weight, stiff mirrors are required. In the case of metal substrates, the coating improves the reflectance and makes the surface more durable and resistant to scratches.
What are mirror coatings?
Mirror coatings are applied to lenses by a vacuum application of interference layers made of powdered oxides, metals, lacquered plastics or other available compounds. Mirror coatings are composed of constructive interference layers that interfere with light passing through the lens by reflecting light.
Can you remove silver coating from a telescope?
It also dissolves an old silver coating nearly instantaneously, but the Angel Gilding kit includes a silver remover that works just as fast. If you’ve never made a mirror or stripped an old coating before, this step will probably give you pause. “Telescope mirrors are delicate, precision optics and shouldn’t be touched!”
What do you use to over coat a telescope mirror?
Silvering: using a silver spray double nozzle gun, spray 3% solution of PChrome S silver solution and a 3% solution of PChrome RX reducer solution until a bright, highly reflective first surface mirror is obtained. This is followed by DI water rinsing and drying the mirror completely before the final step of overcoating.
How long does the coating on a telescope last?
While it’s true that the aluminized surface of a telescope mirror will deteriorate over time, there is no hard and fast rule about how long this will take. Some coatings last only a few years, while others will outlast you. Indeed, the coating on my very first reflector telescope looks absolutely perfect in spite of being more than 30 years old.
What’s the best way to remove aluminum from a telescope?
The first step is removing the old aluminum coating first. Ferric chloride is a good choice because it dissolves aluminum while leaving the glass alone. It does an excellent job but may take an overnight soak for it to completely remove the old coating.