The next obvious question to me is, what it the right (careful) way to clean a newtonian mirror?

I have read somewhere that using a mild dish soap like Dawn is prefered. Any wiping or rubbing will grind dirt into the mirror. So how do you get the dirt off? How about using an old shaving brush (probably couldn't find one these days) or a photo air brush?

Jim Gibson

 Chuck Hards <chuckhards@yahoo.com> wrote:

I would agree for the most part with Kim, except that
a proper cleaning job really isn't "dangerous" if you
are very careful. Aluminum is a soft metal, and
coatings are very thin, but mirrors can be cleaned
without damage. It's only intimidating the first
time.

I only clean mine every other year, unless absolutely
needed.

An improperly cleaned SCT corrector or refractor
objective will take damage also, it's just not as
visible at a casual glance as a reflective surface.

Remember, too, that SCT's do not have sealed
interiors, sooner or later they will require cleaning
interior surfaces also.

C.

--- Kim Hyatt wrote:
> I only clean my Newtonian optics about once per
> season. One reason is that
> scrupulously clean optics are not necessary for most
> observations. (In fact,
> it's my understanding that optics are cleaned
> infrequently at professional
> observatories, also.) You are correct that cleaning
> is "dangerous," and
> that's another reason not to clean too often. I
> believe that the optical
> coatings on a SCT corrector are as soft if not
> softer than the aluminum
> coating on any mirror. I've owned Newtonians for
> most of my astronomy life
> and just haven't found it to be all that much of a
> hassle to clean the
> optics.
>
> -----Original Message-----
> From: Joe Bauman [mailto:bau@desnews.com]
> Sent: Monday, March 24, 2003 7:22 AM
> To: Astronomy in Utah
> Subject: Re: [Utah-astronomy] SCT or Newtonian?
>
>
> I'd like to chime in with a question that has always
> puzzled me. A know
> some prefer SCTs because they are more compact, but
> I am wondering about
> another feature: the fact that the mirrors of
> Newtonians are open to the
> air. Doesn't this allow a lot of grit and dust to
> cover them, for example
> while observing from the Wedge? And isn't it more
> dangerous for the optics
> to clean the mirror than the covering lens of an
> SCT? Thanks, Joe
>
> Joe Bauman
> science & military reporter
> Deseret News
> bau@desnews.com
> (801) 237-2169
>
>
>
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