Why Dawn?

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.

Dom Q.
Slowly yielding to the digital revolution.

>>>>What does dawn have that other liquid dishwashing detergents don't?

Nothing. And that is why one uses it. Others commonly have scents, dyes, hand softeners, lotions, and other things you do not want. And some versions of Dawn have some of these things. Some forms of Ivory, and even other dishwahing liquids are just as pure as Dawn, and have been recommended. The key is to avoid additives.

Photoflo is probably good too--but may be expensive.

Alex

Dawn rinses clean and leaves no residue. It has no harmful chemicals in it. Use a lot of tap water to do a first rinse and that will remove most of the dirt. Warm water is better than cold as it is a better solvent. Rinse well with tap water before the distilled water too. I have posted a detail method before. You could look it up if you wished.