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Old 21-08-2019, 06:24 AM
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LewisM is offline
Join Date: Aug 2012
Location: Somewhere in the cosmos...
Posts: 9,988
That's definitely dew marks left on the FRONT of the lens. They are so tenacious as to not even budge with usual cleaning so people tend to think they are BEHIND the elements, which they aren't. Can be easily removed with good tissues and saliva (yes, SALIVA - Roland from AstroPhysics even says this). Or you can buy really expensive unnecessary fluids to do the same job.

Roland's suggestion is to moisten a CLEAN fingertip with your tongue and rub it around. Follow up with regular lens cleaning solutions and good quality tissues (like KimWipes). He also suggests acetone and denatured alcohol (metho).

His EXACT words:
"To get rid of the shiny spots, we have to use a magical cleaner, which is available at no charge to everyone. That cleaner is saliva. Rub the surface where the shiny spots are with your finger moistened with saliva (don't worry, the finger will never scratch the surface of the coatings because it is the most ideal cleaning pad available for delicate optics. No cleaning cloth is as gentle as the human skin.) This must be followed immediately by either Purosol or Baader Optical Wonder applied with Kleenex so that the saliva does not remain on the surface more than a few seconds. You may have to repeat this procedure a few times for stubborn spots, but eventually they will grow smaller and disappear"

He's the optical designer, hand-figurer and owner of AstroPhysics...I think he knows a thing or 2.

Last edited by LewisM; 21-08-2019 at 06:36 AM.
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