Mold and mildew

I've lately noticed some mildew growing on the lower walls of my observatory. The scope (an SCT) is at second floor level, which appears to be a bit drier, but I'm still concerned about mold and/or mildew getting on the corrector or mirror.

Do others routinely have mildew growing in their observatories? What do you do to protect the optics?

Thanks,
-- Jeff.

Dew Shields? Not too sure but they definitely reduce dew! You can get hard and soft material dew shields! What size is your scope?
Matthew C

Dew Shields? Not too sure but they definitely reduce dew! You can get hard and soft material dew shields! What size is your scope?
Matthew C

Matthew --

I've got a dew shield on order. (I also keep my dew heater on low even when not observing, so I guess I'm more concerned about the main mirror than the corrector.) Scope's a 16" LX200GPS.

Thanks,
-- Jeff.

oh boy, keep that mildew away from the corrector, :shock:
It can actually eat into the anti-reflective coatings and is impossible to get off without damaging the glass. Same applies to putting the cover over the front of the scope if the plate/lens is dued over, NEVER put the cover on the front of a dewed up scope, wait until the next morning to let the dew evaporate.

The mirror is fairly protected especially if you use something like a skylight 1A "filter" to seal the tube.

As for mildrew on concrete wall, might this be a sign of rising damp?, I'm not a construction person, so I really dont know?

Wow! A Fine piece of equipment! I know of some one in the states that a keeps a dehumidifier going 24/7 in his observatory! A bit extra on the old electricity bill but if it does the job, so what!
Matthew C

...
As for mildrew on concrete wall, might this be a sign of rising damp?, I'm not a construction person, so I really dont know?

Dave --

Generally, I would think so. But the walls are timber-framed, and sit on top of a ring of torch-on-felt. The concrete pad also has a damp-proof course under it, so I would think I'd be well-protected against rising damp.

On the outside of the plywood is a layer of roofing felt, expanded metal, and sand and cement plaster. Of course, there are a bunch of holes in the felt made by the screws holding the expanded metal on -- I wonder if I'm getting water penetration through the plaster and holes in the felt? But that doesn't seem very likely either....

-- Jeff.