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  1. #1
    John Lepps's Avatar
    John Lepps Guest

    Default solution and procedure for cleaning SCT corrector?



    Upon bringing in my SCT from a recent observing session, I've noticed a few
    dew/ frost spots on the corrector as well as some non-fingerprint smudges.
    I lost my Celestron manual, but what is the procedure/ solution content for
    cleaning the corrector?

    Thanks,
    John



  2. #2
    Duke's Avatar
    Duke Guest

    Default solution and procedure for cleaning SCT corrector?

    Goto www.arksky.org and select "guides" from the menu on the left side of
    the screen. About half a screen down on the guides window you will see "ASO
    fine optics CLEANING SYSTEM: Part 1".
    This is probably one of the safest and widely used methods you can use.
    Do keep in mind however, no cleaning at all is usually the best option!
    People with expensive optics often never touch the lens for cleaning or
    otherwise. When selling a good scope you may be asked if the optics have
    ever been cleaned. If you have to answer "YES" you could lose a sale.
    George D
    "John Lepps" <jlepps@jex.net> wrote in message
    news:gHQLd.5164$S3.3351@newsread2.news.atl.earthli nk.net...
    few
    for



  3. #3
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default solution and procedure for cleaning SCT corrector?

    On Tue, 01 Feb 2005 19:23:56 GMT, "John Lepps" <jlepps@jex.net> wrote:


    I've had excellent results for many years with Windex and Kleenex, both
    by brand name. Probably more important than the exact formula you use
    for cleaning is the need to gently remove dust first (by brushing,
    blowing, or both). It is doubtful you will ever have problems with a
    cleaning solution damaging the AR coating, but scratches are fairly easy
    to make if you have something abrasive on the surface.

    BTW, it is a good idea to keep the corrector spotless. Unlike a dirty
    mirror, which only has minor impact on the image, a dirty corrector
    seriously degrades contrast if you have any stray light at all hitting
    it. Also, a clean corrector is considerably more resistant to dew
    formation. I clean mine every week or two in the summer when dust and
    pollen is about, and perhaps monthly in the winter.

    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

  4. #4
    John Lepps's Avatar
    John Lepps Guest

    Default solution and procedure for cleaning SCT corrector?

    Thank you! I think those are the *best* instructions I've seen regarding
    cleaning specific optics!

    John

    "Duke" <gemduke@bellsouth.net> wrote in message
    news:PTQLd.22786$t67.21780@bignews5.bellsouth.net. ..
    "ASO
    smudges.



  5. #5
    John Lepps's Avatar
    John Lepps Guest

    Default solution and procedure for cleaning SCT corrector?


    "Chris L Peterson" <clp@alumni.caltech.edu> wrote in message
    news:1umvv0hauckep313iekjqqmg339l1f1b6f@4ax.com...
    few
    smudges.
    for

    Yeah, I already tried the routine for trying to blow/ remove "dust".
    However, what I've had is actually pollen stuck to the corrector after many
    nights of dewing. I really wasn't concerned with it, but was concerned with
    some of the small smudges I've gotten, made worse by regular dewing. Those
    had to come off.

    It is doubtful you will ever have problems with a

    I guess that's why I don't apply pressure- just drag the cotton across the
    surface.


    Never had to have your corrector recoated from frequent cleaning? According
    to the great instuctions in the post by Duke, every time an optical surface
    is cleaned, no matter what precautions are taken, some of the optical
    coating comes off. I don't know this for a fact, but that's what I just
    read.

    Thanks for the info.

    John





  6. #6
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default solution and procedure for cleaning SCT corrector?

    On Wed, 02 Feb 2005 15:42:24 GMT, "John Lepps" <jlepps@jex.net> wrote:


    Pollen is a big concern- when combined with dew, it produces acids that
    will etch your corrector coatings. The good news is that it won't
    scratch, so whatever doesn't easily blow off can be lifted with fluid.
    If you live in an area that has any significant air pollution, other
    dust may also form acid when combined with dew. In any case, the
    combination of a dirty corrector and cycles of dewing is far more likely
    to damage your optics than anything you do while cleaning.



    It's safe enough to apply light pressure to a coated corrector.



    Technically that's true, but in the case of AR coated glass, you are
    probably talking thousands of cleaning cycles before any coating loss
    would become significant. One of my SCTs has had its corrector cleaned
    ~250 times, the other ~75 times, and both look as good as the day I got
    them.

    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

  7. #7
    Ralph Hertle's Avatar
    Ralph Hertle Guest

    Default solution and procedure for cleaning SCT corrector?

    John Lepps wrote:
    [clip]



    J.L. and C.P.:


    Windex or other compound containing ammonia liquid should not be used with
    fluorite coated optics. The ammonia reacts with the coating.

    Isopropyl alcohol is the best for fluorite coatings, says the maker of my
    computer monitor that makes coated screens. That also cleans up
    fingerprints in two or three applications with cotton. Technical and
    reagent grade may be more expensive than necessary, and 75% drug store
    Isopropyl alcohol may work well.

    Two or three cleanings will clean off the thin film of airborne auto engine
    oils that may be originate from the local expressway. you don't see the
    film until you touch the lens surface. The glossy surface will become
    noticeably darker and duller with cleaning. The transparent color changes
    from glossy pink to a dull purple cast. Rubbing may In time wear off the
    minutely thin layer of soft fluorite material.

    Kleenex contains minute particulate dust abrasives and rough fibers and
    should not be used.

    I'm not certain that biologically clean medical cotton balls are that dust
    and abrasive free. They probably are, however, I'd research that a bit.
    Purpose-made optical cleaning cotton and pads are available.

    Nice contributors have posted:

    http://www.thermo.com/eThermo/CMA/PD...0001028574.pdf

    http://astronomy.trilobytes.com.au/s...t.htm#cleaning


    Ralph Hertle

  8. #8
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default solution and procedure for cleaning SCT corrector?

    On Wed, 02 Feb 2005 21:43:42 GMT, Ralph Hertle
    <ralph.hertle@verizon.net> wrote:


    I'm not exactly sure what "fluorite" coatings are. However, I've used
    Windex for years to clean standard magnesium fluoride AR coatings on my
    telescopes, cameras, and also in the lab for laser optics.

    White, unscented, unlotioned Kleenex is entirely free of abrasives. I've
    looked at enough of it under the microscope. I've never scratched an
    optic using Kleenex, and it works much better than pure cotton.

    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

  9. #9
    Bill Tschumy's Avatar
    Bill Tschumy Guest

    Default solution and procedure for cleaning SCT corrector?

    On Wed, 2 Feb 2005 15:43:42 -0600, Ralph Hertle wrote
    (in article <4201498C.2050003@verizon.net>):

    .....

    Al Nagler himself recommends both Windex and Kleenex. Please see:

    < http://www.televue.com/engine/page.asp?ID=143>





  10. #10
    Chloe_yamato@yahoo.com's Avatar
    Chloe_yamato@yahoo.com Guest

    Default solution and procedure for cleaning SCT corrector?


    John Lepps wrote:
    a few
    smudges.
    content for

    you should clean off as much grit as you can with running water first.
    then I found lightly washing the lens with ivory soap gets off the
    fingerprints. isopropyl alchohol (drugstore variety) will rinse off the
    residue. distilled water to rinse the alchohol and kleenex to remove
    the water. if you dont remove the water you will get spots. you dont
    necesairily need the last step because the spots dont affect
    performance.

    chloe


 

 
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