Cleaning of the Primary mirror (Newtonian)

Started by qbose, 10/20/2005 02:55AM
Posted 10/20/2005 02:55AM Opening Post
I have successfully cleaned several mirrors of used scopes I've bought over the years by following a simple procedure. Before I say how I would like to hear from others to see what they have done. It's not as hard as everyone makes it out to be.
The method came from the manual of first Newtonian I bought and I didn't know any better and I believed it to be gospel and it made sense.
I believe not cleaning will cause the coating to deteriorate quicker over time because of natural interaction of the coatings with contaminates that will fall on the mirror and eat away at the coating. So in my opinion a heavily used mirror should be cleaned at least every year and a half or at least every 2 years assuming buildup of dust. Also the dust holds the moisture more easily so the mirrors fog up easier on an all nigher. Opinions.
Posted 10/20/2005 03:40AM #1
Hi Greg,
I keep my mirrors clean, not pristine all the time, but I do not allow a build up of pollen and air born sap and chemicals.
I use the soak and rinse method. I place the mirror in the bathtub on it's back and rinse the mirror with warm water from the tap with a bit of force. Then I let the water sit in the bowl shape and I put in a few drops of Dawn detergent. I let that sit for about 3-5 minutes and I rinse thoroughly again. Once more I put Dawn in the bowl and this time I use a few cotton balls, place them in the water and move them around the mirror with just their own weight. Then a final rinse and I stand it up on a wash cloth on the side of the tub and do a full rinse with distilled water, a good rinse. I then use a hair drier on cold to blow as much of the water drops off the surface without drying them and then I dab off the rest using a Kleenex tissue. Afterward I place the dried mirror on the table and look at it in the light for any residue. If there is any streaks or foggy residue I clean that by lightly rubbing the mirror with clean cotton balls. This is a light polishing action that will remove any hazing without any scratching.
This has proved to work very well for me.

[SIZE="Large"][/SIZE][COLOR="Blue"][/COLOR] Floyd Blue grin
Amateur Imager
Posted 10/20/2005 12:07PM #2
I use a clean designated microfiber cloth to remove any water droplets that didn't sheet off the mirror. Just touching the corner of the cloth to the droplet. It absorbs 100% of the excess water. This way nothing is left behind on the mirror to stain the coatings.

Jay
Posted 10/20/2005 01:41PM #3
Hi:

I use essentially the same system that Floyd does, tap water with a bit detergent, soak it, clean it gently with "Surgical" Cotton Balls, rinse with distilled water. The Surgical Cotton is sterile and I read somewhere that it is dust free, unlike standard cotton balls which are designed for external use.

Regarding a dirty coatings deteriorating more quickly...

I recent bought a RV-6 that that had been sitting in a garage uncovered for many years. The house was within a few blocks of the ocean and the mirror was very dirty/dirty looking.

I cleaned it by soaking it etc and even though the coatings are quite old, they look fine and seem to provide nice bright images...

jon isaacs
Posted 10/20/2005 02:09PM #4
Kim,

You said "It's not as hard as everyone makes it out to be."

I don't think most telescope owners think it is hard, so much as risky--you have to remember to do things carefully. But the procedure, as explained by the other posters, is not difficult. As long as you let the cotton balls work on their own weight you should be Okay.

Alex