To all you magicians out there. Unlike Floyd Blue, I have always owned and used, exclusively, refractors for observing. And like him I recently purchased one of the other kind -- Floyd a 5" refractor, me a 10" f/5 Newtonian to go a little deeper than my 6" Starfire.
I've read many posts on this forum on how to clean a Newtonian mirror. Many of them recommend using a tap water bath with Dawn dishwashing detergent. My question is, why Dawn, and if so which Dawn -- ultra? regular? scented, etc. (Ultra dawn was recommended to me to kill the moss that grows between the bricks of my walkway. It looks nice, but the moss gets very slippery in wet or damp weather and can become a real safety hazard.)
What does dawn have that other liquid dishwashing detergents don't (moss killing properties aside)that makes it the choice for cleaning mirrors? Wouldn't Ivory Liquid do? (That's what my wife buys for our dishes.) Or perhaps Kodak Photoflo? I have a quart of the latter sitting in my now defunct, obsolete, dust-collecting, decaying darkroom.
Slowly yielding to the digital revolution.