fungal spore on primary mirror

[Sammyb]

Hello all,

My newt has been sat in the garage for a few months during the summer/bad weather. I had a look today and noticed a what looks to be a fungal spore/growth on the primary - it is quite transparent and circular - about 6-8mm in diameter. I don't expect this to degrade the optical quality but I wondered if this was a common problem and if it needs to be removed in case it damages the mirror/grows too big?

It hasn't been stored in any damp conditions at all.

Cheers,

sam

[JB80]

I'm not sure but if it is a fungal growth I don't think I'd be wanting a stray spore finding it's way to any other optics that may go near the scope.

It's not something I have had the pleasure of dealing with so couldn't really give any advice but I think I would be wanting to give the primary a bit of a bath if for no other reason to halt any growth there is, especially now the weather is on the up and humidity may set in.

Just my 2p though.

[Capricorn]

If it is a fungal growth then I would remove it. I would expect that it is damaging the mirror and it will spread.

[Moonshane]

could be fungal growth but more likely to be a condensation spot. best to air things out occasionally and have a weekly check to make sure that dew is not forming on optical surfaces.

[TheNorthernMonkey]

Multiple post. whoops

[TheNorthernMonkey]

Fungus is killed by exposure to UV light. point it at a bright area of sky during the day for a while

[Ganymede12]

Fungus is killed by exposure to UV light. point it at a bright area of sky during the day for a while

Now would be a good time to start solar viewing!

[TheNorthernMonkey]

Now would be a good time to start solar viewing!

Perhaps not quite that much UV but certainly for camera lenses, its recommended to use them every few months just to keep any fungus at bay. You only get really bad outbreaks on lenses which have been stored for ages.

[Sammyb]

OK thanks chaps. I'll keep an eye on it for now. I'm not keen on messing with the primary at the moment. If it looks like its getting bigger I'll remove it. I'm not 100% sure it is a fungus - i'd be surpised as its only been stored for a few weeks unused and in a dry garage.

After a nights viewing would you usually allow a newtonian to air off prior to putting the end cap on to get rid of any dew?

Sam