Mould on Sky90 lens

[AstroApprentice]

I noticed this Tak Sky90 on eBay:
https://www.ebay.com.au/itm/Takahashi-Sky-90-Fluorite-Doublet-Refractor-Telescope/273523131651?hash=item3faf3fc503%3A g%3AVLUAAOSw8KJbz-f4&LH_ItemCondition=3000
Mould on lens looks bad, but is it cleanable?

[Kunama]

Jason, at that price you would be gambling a lot. The Sky90 or FCL90 is different to most other FC Taks in that it is has a wide air space behind the CaF2 element which is the exposed element ahead of the flint. Though coated, with the fungus damage so widely spread, it would not be a scope I would be interested in. Polished CaF2 is very resistant to moisture entry but if the fungal attack has damaged the actual polish on the element then you could end up with a very cloudy objective....

(Other FC Taks have the CaF2 element behind the front element)

Edit: $1800 is about the right price for a mint example of the FCL90

[LewisM]

We’ve discussed this scope in general chat. Way overpriced and not worth the gamble

[AstroApprentice]

Thanks for the sage advice.