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Cleaning a mirror



 
 
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  #1  
Old January 3rd 06, 01:19 AM posted to sci.astro.amateur
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Default Cleaning a mirror

I borrowed an Odyssey 1 (16", I think) telescope from my school. I
started looking at some stars and Mars and noticed that the telescope
seemed badly out of collimation (it was collimated before leaving school, I
figured the transport changed that). Well, collimation still seemed ok,
but I found that the mirror is extremely dirty.

Is there a good way to clean the mirror? Can I just pop the back
open, take the mirror out, and clean it with a water/isopropyl alcohol mix,
or is this something I shouldn't mess with?
  #2  
Old January 3rd 06, 01:56 AM posted to sci.astro.amateur
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Default Cleaning a mirror

Is there a good way to clean the mirror? Can I just pop the back
open, take the mirror out, and clean it with a water/isopropyl alcohol
mix,
or is this something I shouldn't mess with?


If it was your scope, I would advise you to live with the dirty mirror until
you couldn't stand it any longer, and only then clean it. However, since it
is not your mirror I think it is unwise to mess with it no matter how dirty.
Dirty mirrors work surprisingly well.

Dennis


  #3  
Old January 3rd 06, 01:56 AM posted to sci.astro.amateur
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Default Cleaning a mirror

http://www.astro-tom.com/tips_and_ad...ing_optics.htm

  #4  
Old January 3rd 06, 02:47 PM posted to sci.astro.amateur
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Default Cleaning a mirror

In article ,
Cerdic wrote:

I borrowed an Odyssey 1 (16", I think) telescope from my school. I
started looking at some stars and Mars and noticed that the telescope
seemed badly out of collimation (it was collimated before leaving school, I
figured the transport changed that). Well, collimation still seemed ok,
but I found that the mirror is extremely dirty.

Is there a good way to clean the mirror? Can I just pop the back
open, take the mirror out, and clean it with a water/isopropyl alcohol mix,
or is this something I shouldn't mess with?


Do not attempt to clean the mirror. A 16" Odyssey is not appropriate
for anyone to practice on. Discuss the matter with the school.
  #5  
Old January 3rd 06, 04:32 PM posted to sci.astro.amateur
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Default Cleaning a mirror

On 03 Jan 2006 01:19:52 GMT, Cerdic wrote:

I borrowed an Odyssey 1 (16", I think) telescope from my school.
Is there a good way to clean the mirror?


As others have suggested: Don't attempt to clean that mirror!
Reason: The telescope isn't yours. It's very easy, despite having the
best of intentions, to damage the mirror and/or its coating(s).
Furthermore, it would be good to know the nature of the coating(s) on
the mirror prior to attempting a cleaning. One might assume (possibly
incorrectly) that the reflective coating is either itself very hard or
coated with a hard overcoating. Even if that were so, it's easy to
error when one has little or no experience cleaning first surface
telescope mirrors.

I don't know how you determined that the mirror was in need of
cleaning, but shining a light onto a Newtonian telescope's primary
mirror will make all but the cleanest of mirrors appear to be in need
of cleaning.

One should gain experience cleaning telescope optics using one's own
telescopes -- preferably starting with relatively inexpensive
telescopes before considering cleaning someone else's telescope
optics. You reacted wisely in seeking advise prior to acting. For
this you are commended!

If the mirror(s) of the school's telescope is/are truly in need of
cleaning, I would suggest that the school contact an individual with
experience cleaning high quality, first surface telescope mirrors.
It's just too easy to make a costly mistake.

Sketcher
To sketch is to see.
  #6  
Old January 3rd 06, 05:07 PM posted to sci.astro.amateur
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Default Cleaning a mirror

Cerdic wrote:
I borrowed an Odyssey 1 (16", I think) telescope from my school. I
started looking at some stars and Mars and noticed that the telescope
seemed badly out of collimation (it was collimated before leaving school, I
figured the transport changed that). Well, collimation still seemed ok,
but I found that the mirror is extremely dirty.

Is there a good way to clean the mirror? Can I just pop the back
open, take the mirror out, and clean it with a water/isopropyl alcohol mix,
or is this something I shouldn't mess with?


I doubt you still want to clean it after all these advice.

But if so, follow that procedure :

1. carefully look at the primary
2. consider his size and the time and energy
it would cost to resurface it in case of problem
3. delay the operation to next year.
4. in one year, iterate from step 1

-- francois meyer
http://dulle.free.fr/alidade/galerie.php?maxim=12
  #7  
Old January 3rd 06, 07:16 PM posted to sci.astro.amateur
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Default Cleaning a mirror

Cerdic wrote in
54:

I borrowed an Odyssey 1 (16", I think) telescope from my
school. I
started looking at some stars and Mars and noticed that the telescope
seemed badly out of collimation (it was collimated before leaving
school, I figured the transport changed that). Well, collimation
still seemed ok, but I found that the mirror is extremely dirty.

Is there a good way to clean the mirror? Can I just pop the
back
open, take the mirror out, and clean it with a water/isopropyl alcohol
mix, or is this something I shouldn't mess with?


Ok, on everyone's advice, I won't attempt to clean it.

So, I'm back to collimation... I tried tweaking the collimation by
adjusting the primary mirror, but the screws do absolutely nothing. I
don't think the scope has been used in ages and probably needs some
maintenance performed on it. I guess that I'll just haul it back to
school.
  #8  
Old January 3rd 06, 07:34 PM posted to sci.astro.amateur
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Default Cleaning a mirror

So, I'm back to collimation... I tried tweaking the collimation by
adjusting the primary mirror, but the screws do absolutely nothing. I
don't think the scope has been used in ages and probably needs some
maintenance performed on it. I guess that I'll just haul it back to
school.


Collimating a dob is not a big deal. Assuming that the scope is not really
banged up/disassembled/etc, there are only two adjustments to make. 1) The
secondary mirror (the little one just inside the focuser) needs to be tilted
so that, when looking through the focuser, it points at the center of the
primary mirror. 2) The primary mirror needs to be tilted so that it points
at the center of the secondary. Do a Google on "collimation", experiment a
bit, and I bet that you will figure it out. Not all that difficult, but
necessary for getting good views.

Dennis


  #9  
Old January 3rd 06, 07:40 PM posted to sci.astro.amateur
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Default Cleaning a mirror


Cerdic wrote:
Cerdic wrote in
54:

I borrowed an Odyssey 1 (16", I think) telescope from my
school. I
started looking at some stars and Mars and noticed that the telescope
seemed badly out of collimation (it was collimated before leaving
school, I figured the transport changed that). Well, collimation
still seemed ok, but I found that the mirror is extremely dirty.

Is there a good way to clean the mirror? Can I just pop the
back
open, take the mirror out, and clean it with a water/isopropyl alcohol
mix, or is this something I shouldn't mess with?


Ok, on everyone's advice, I won't attempt to clean it.

So, I'm back to collimation... I tried tweaking the collimation by
adjusting the primary mirror, but the screws do absolutely nothing. I
don't think the scope has been used in ages and probably needs some
maintenance performed on it. I guess that I'll just haul it back to
school.


Hi:

The Odyssey uses push pull bolts for collimation. Unlock the locking
bolts (the bolts are in pairs, one is a lock bolt, one an adjustment
bolt) and collimate. Not easy for a beginner. Like the mirror, probably
best just to leave it alone. The ol' 13.1 was not a bad scope, but not
overly user friendly when it came to collimation (though once you had
it "in" and the bolts locked down, it held its adjustments well.

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Join the SCT User Mailing List.
http://www.groups.yahoo.com/group/sct-user
============================
See my home page at
http://skywatch.brainiac.com/astroland/index.htm
for further details!
============================
For Uncle Rod's Astro Blog See:
http://journals.aol.com/rmollise/UncleRodsAstroBlog/

  #10  
Old January 6th 06, 02:39 PM posted to sci.astro.amateur
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Default Cleaning a mirror

RMOLLISE wrote:

Cerdic wrote:
I borrowed an Odyssey 1 (16", I think) telescope from my school. I
started looking at some stars and Mars and noticed that the telescope
seemed badly out of collimation (it was collimated before leaving school, I
figured the transport changed that). Well, collimation still seemed ok,
but I found that the mirror is extremely dirty.

Is there a good way to clean the mirror? Can I just pop the back
open, take the mirror out, and clean it with a water/isopropyl alcohol mix,
or is this something I shouldn't mess with?


Hi:


The Odyssey I is a 13.1" scope (the next size up, the Odyssey II was
17.5"). At any rate, _leave it alone_. You won't help anything and will
possibly do major damage to a scope that doesn't belong to you.



OK, folks, from just up the road from Uncle Rod - I find myself with
a dirty mirror on a classic Odyssey 10", courtesy not of the local
flooding occasioned by a burst washing-machine hose, but from its
cleanup. While I was away giving a final exam, the cleanup crew
ripped up three rooms of carpet and pad, and left ten industrial-
strength driers blowing across wet particle board. Also while I was
away, their breeze caught the dropcloth ove rthe 10", blew it away,
and put a substantial layer of, well, particles on the primary.
I was initially worried about the stuff being abrasive, so I
took a while using blown air (the only canned air I had has too
much in the way or propellants), clean cotton balls, and eventually
alcohol and distillled water. No visible scratches, but I do still
have some crud. Is my best plan (once all the cleanup is finished...)
to bathe it in a distilled water/alcohol mixture, or what?

Bill Keel
 




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