[AZ-Observing] Re: oh-oh... mirror cleaning time

Hi Stan:

I think there's a wide variety of opinion out there on primary cleaning.  I=
 for one think that it is vital, and clean mine usually twice a year, three=
 times if it's very bad.  The reason for this is that the coating should be=
 replaced every 4-5 years anyway, and I'd rather trade a little mileage on =
the coatings and observe with a clean mirror surface.  Our AZ sites certain=
ly generate enough dust & debris for me to notice a contrast difference aft=
er a few months when it gets very bad.

First, blow off any loose dust or particles with an air bulb or a can of co=
mpressed air.  I usually fill my tub part way with water, putting down a to=
wel so the glass is cushioned.  I add just a couple drops of Palmolive or S=
unlight dishwashing soap.  (I find that Dawn is somewhat more difficult to =
rinse off).  To clean the mirror, I use a rolled, sterile, surgical cotton =
(buy at Walgreens or Osco) and just move it gently over the surface of the =
mirror, using ONLY the weight of the cotton for pressure.  Don't apply any =
additional pressure when cleaning. I do this for a couple minutes to make s=
ure everything gets removed from the surface.  I then drain the tub and do =
an initial rinse with regular water.  Then I finish the rinsing with 3 or 4=
 gallons of DISTILLED water to avoid any spotting - just pour it out of the=
 jug onto the mirror, being careful to keep the mouth of the jug away from =
the mirror.  To dry the mirror I lay a towel down, turn the mirror up on it=
's edge and lean it against a pillow to let it air dry for about 10 minutes=
.  If any water remains, you can blow it off with the bulb or compressed ai=
r. =20

As for the secondary, mine doesn't get as dirty as the primary so I only cl=
ean it once a year, using a similar method for the primary, except in the s=
ink rather than the tub.  I haven't found a good way to do a thorough clean=
ing on the secondary without removing it from the spider.  Hope this helps =
- good luck.

-Kerry Weatherford



-------Original Message-------
From: StanFM@xxxxxxx
Sent: 04/28/03 06:44 AM
To: az-observing@xxxxxxxxxxxxx
Subject: [AZ-Observing] oh-oh... mirror cleaning time

>=20
> It's been some years since I attempted a primary (12.5") mirror cleaning.=
..=20

but I can't put it off any longer.  I plan on holding it vertically next
to=20
the sink and spritzing some bottled water on it.

Any suggestions... and or, anything I must avoid?  How about a surfactant
of=20
some kind?  Is there a way of doing the same for the secondary without=20
removing it from the vanes in the tube?  (I'm assuming that the salt in my=
=20

softened water would be bad for the coating.)

I know you should avoid this at all costs, and I have for years.  I think
now=20
is that time.  Your suggestions will be taken to heart!

Stan F.


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