Took down the roof camera at my observatory for the first time in years to replace the plastic dome and clean the internals (lots of dead bugs!) and while cleaning the Fujinon fisheye lens, I noticed that part of the lens surface is actually very rough under the pec pad I was using to clean it. I tried wiping the area multiple times, cleaning it multiple times, and it didn't change at all. What might this be? Any ideas how I might clean it? The image with the dots on the lens is it before I cleaned it.
Tried that already. I was wetting pec pads with isopropyl and I got most of the initial gunk off, but not these weird stains. I wonder, could it be a fungus that's eaten the lens coating?
If you have some bio matter sitting on a coated piece of glass for a while, it tends to eat the coatings. Unfortunately.
I had a look at this as well. I suspect you've got fungus that formed as a result of the "biologicals", and it has somewhat eaten the coatings. First Contact Polymer from www.photoniccleaning.com would be a possible option. This is like the old flexible collodion method, where the polymer bonds lightly to the coatings, but sticks to the organics, and peels off. You might be able to use "Eclipse Optic Cleaning Fluid" from Photosol https://photosol.com/products/eclipse-optic-fluid/which has a methanol base, and will remove oils and some organics, similar to the isopropyl. Inverting the lens and putting into a shallow bath of hydrogen peroxide may also help. Exposing the unprotected lens (off camera) to UV should stop further fungus growth.
