Go Back   IceInSpace > Equipment > Equipment Discussions

Reply
 
Thread Tools Rate Thread
  #1  
Old 15-02-2018, 09:14 PM
Space Cadet (Greg)
Registered User

Space Cadet is offline
 
Join Date: Dec 2017
Location: Adelaide, Australia
Posts: 8
mirror and lens cleaning

Hello all,
I have recently acquired a second hand scope and equipment and am looking for some wisdom regarding mirror and lens cleaning.
Do's and don'ts etc.
I hear windex is a big no-no for example.

I am reasonably handy but dont want to damage my new baby
Thank you all in advance
Greg
Reply With Quote
  #2  
Old 15-02-2018, 09:41 PM
astronobob's Avatar
astronobob (Bob)
Casual Cosmos Capturer

astronobob is offline
 
Join Date: Jun 2010
Location: Gold Coast SE QLD
Posts: 4,190
Hi Greg, yes, Do Not use any window cleaning agents or any other chemical cleaners of any sorts on a telescope Mirror/s until you find/read/research with in astro community and here IceInSpace- ?
What telescope do you have, I only ask as you are quite new & it will very well help others to respond to your question ..

I have had a quick look through & nothing popping out as to mirror cleaning, yet, but below are two 'links' on cleaning lenses, do not use these cleaning tips on Mirrors, mirrors are totally different ball-game

1) http://www.iceinspace.com.au/forum/s...d.php?t=149868
2) http://www.iceinspace.com.au/forum/f...splay.php?f=20

Have a good look through the Forum, and or Google Search something like - Astronomical Telescope Mirror cleaning !
Rgrds
Reply With Quote
  #3  
Old 15-02-2018, 10:10 PM
astronobob's Avatar
astronobob (Bob)
Casual Cosmos Capturer

astronobob is offline
 
Join Date: Jun 2010
Location: Gold Coast SE QLD
Posts: 4,190
https://www.youtube.com/watch?v=8TObET2F-EA
Reply With Quote
  #4  
Old 15-02-2018, 10:32 PM
luka's Avatar
luka
Unregistered User

luka is offline
 
Join Date: Apr 2007
Location: Perth, Australia
Posts: 1,164
Here is a link to Mirror cleaning article in IIS HowTo section.
Reply With Quote
  #5  
Old 16-02-2018, 06:23 AM
Kunama
...

Kunama is offline
 
Join Date: Sep 2012
Posts: 3,588
Greg, glad to see someone looking for advice first rather than telling a horror story and looking for a fix.
Depending on the amount of dust, crud or marks, you may or may not need to worry about washing the mirror.
Any dust etc will degrade the image but it takes quite a bit of dust before our eyes are able to see that degradation.
I have found that with my previous 18" scope washing the mirror twice a year was enough and it was being used without a shroud at locations where up to 2000 people were milling around kicking up dust.

My mirror cleaning method is quite simple and seems to work well.
I have a garden hose, a small spray bottle with a couple of drops of dishwashing liquid in warm water (not hot !!!) some isopropyl alcohol and 4 litres of demineralised water at the ready....
I place the mirror at a 45º angle on an outdoor chair out of direct sunlight.
I use a a low pressure stream of water from the garden hose to wash any grit and loose dust off the surface, usually for at least 5 minutes.

I then wet the mirror surface with the soapy warm water using the spray bottle and using my fingertips, very very lightly, feel the surface of the mirror for any deposits and keeping the fingers and mirror continually wet with the soapy spray. As soon as I feel anything, I stop and concentrate the spray on the spot till I can no longer feel the blemish. Do not rub the spot, if it does not clear with the spray, I use some isopropyl alcohol on a KimWipe and then rinse immediately.

Once the whole surface is clean I rinse the mirror with a stream of distilled water and leave it to air dry. Though I admit that to speed up the process I do use the corner of a piece of paper towelling to wick away larger droplets.

Fingertips are far more sensitive than cotton balls which can drag a bit of grit across the mirror's surface leaving scratches...

I don't soak the mirror in a tub, preferring to wash with a stream across the surface.... that way the grit doesn't stay on the mirror

( I have seen some people who claim dust has no effect on the use of a mirror, and upon looking into their scopes I would guess that due to the crud buildup the surface accuracy looked more like 1/4" rather than 1/4wave.... but each his own)

Last edited by Kunama; 16-02-2018 at 09:32 AM.
Reply With Quote
  #6  
Old 16-02-2018, 09:36 AM
Wavytone
Registered User

Wavytone is offline
 
Join Date: Jul 2008
Location: Killara, Sydney
Posts: 4,147
Definitely don’t soak the mirror - aluminium coatings invariably have numerous microscopic pinholes and these allow water to work in between the coating and the glass. Water is the main factor that makes pinholes grow.

It’s a trade off between how dirty is too dirty vs when to recoat.
Reply With Quote
  #7  
Old 16-02-2018, 10:11 AM
LewisM's Avatar
LewisM
Novichok test rabbit

LewisM is offline
 
Join Date: Aug 2012
Location: Somewhere in the cosmos...
Posts: 10,388
Quote:
Originally Posted by Kunama View Post

( I have seen some people who claim dust has no effect on the use of a mirror, and upon looking into their scopes I would guess that due to the crud buildup the surface accuracy looked more like 1/4" rather than 1/4wave.... but each his own)
Yeah, I reckon it's time to pull that Mewlon 300 down from Youknowwho and force-clean it.
Reply With Quote
  #8  
Old 23-02-2018, 09:11 AM
Don Pensack's Avatar
Don Pensack
Registered User

Don Pensack is offline
 
Join Date: Aug 2006
Location: Los Angeles
Posts: 501
Mirror cleaning, see https://www.youtube.com/watch?v=9Y8xFnXFVGQ
Eyepiece cleaning, see: http://www.televue.com/engine/TV3b_page.asp?id=103
Reply With Quote
  #9  
Old 14-03-2018, 10:10 PM
Space Cadet (Greg)
Registered User

Space Cadet is offline
 
Join Date: Dec 2017
Location: Adelaide, Australia
Posts: 8
Thank you to all for your info.
Mirror much cleaner now!
Lenses also much less spotty
Cheers
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 11:21 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement
Testar
Advertisement