Fungal growth on optical surfaces

[Captain Scarlet]

Although this thread is 2.5 years old I thought I’d supplement it rather than start anew.

I keep my scopes in a utility room that’s reasonably dry but heated only by an insulated hot water tank and has single-skin walls. It used to be a garage but has been absorbed as more or less part of the main house. Things don’t seem to get rusty whereas in the shed, they do.

Anyway, I inspected my quite old (1991 I think) Intes M603 Mak today and Yikes! I noticed some obvious fungal growth on the corrector plate and on the primary mirror. I don’t recall having seen it before.

 

There was some on the secondary mirror as well. I quickly took it apart and cleaned all the surfaces with a home-brew mixture of propanol, methylated spirit (ethanol), ammonia and distilled water. All surfaces are now free of contaminants and there doesn’t appear to have been any etching. I plan to use some of the mitigations listed above to prevent its re-emergence.

Magnus

[Alien 13]

4 minutes ago, Captain Magenta said:

Although this thread is 2.5 years old I thought I’d supplement it rather than start anew.

I keep my scopes in a utility room that’s reasonably dry but heated only by an insulated hot water tank and has single-skin walls. It used to be a garage but has been absorbed as more or less part of the main house. Things don’t seem to get rusty whereas in the shed, they do.

Anyway, I inspected my quite old (1991 I think) Intes M603 Mak today and Yikes! I noticed some obvious fungal growth on the corrector plate and on the primary mirror. I don’t recall having seen it before.

 

There was some on the secondary mirror as well. I quickly took it apart and cleaned all the surfaces with a home-brew mixture of propanol, methylated spirit (ethanol), ammonia and distilled water. All surfaces are now free of contaminants and there doesn’t appear to have been any etching. I plan to use some of the mitigations listed above to prevent its re-emergence.

Magnus

Glad you caught it in time, everyone should inspect there optics regularly and clean them if there is the slightest hint of fungus...

Alan