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Washing a mirror without breaking it (video)

Dob Optics Reflector
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15 replies to this topic

#1 JJDreese

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Posted 26 October 2021 - 11:27 PM

I've cleaned the mirrors on all of my Dobsonians and wanted to share my method. It's basically the method outlined in the Orion XT user manual.

Had a lot of fun making this video. Hope you find it entertaining too (my kids both helped me).

 

https://youtu.be/wtc53Br_96g

 

I'm always looking for ways to improve these videos, so feel free to send feedback.

 

John

 


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#2 SteveG

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Posted 27 October 2021 - 02:48 PM

I've cleaned the mirrors on all of my Dobsonians and wanted to share my method. It's basically the method outlined in the Orion XT user manual.

Had a lot of fun making this video. Hope you find it entertaining too (my kids both helped me).

 

https://youtu.be/wtc53Br_96g

 

I'm always looking for ways to improve these videos, so feel free to send feedback.

 

John

Nice video. What do you use for video editing? I'm just getting started with making an instructional video.



#3 havasman

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Posted 27 October 2021 - 03:25 PM

https://www.youtube....h?v=9Y8xFnXFVGQ

 

This method is usually considered superior to the older cotton balls method. 

 

"Here is the most important thing about coatings - the enemy of a coating is moisture, in the form of liquid water and humidity.

Think of it this way - whenever moisture is in contact with the coating of your mirror, the clock is ticking.  There is only a finite time that the coating will stay undamaged when in contact with water, so it is best to minimize the time that the mirror is wet or is in very wet surroundings."  - Mike Lockwood from his website Loptics.com article Cleaning your mirror, and prolonging coating life which is found here -  http://www.loptics.c...mirrorcare.html

 

My recommendation for improvement is presenting the best available methods. Form is less important than content.

 

Sadly, youtube has become primary source reference for astro newbs. It is extremely common for misinformation to be spread this way. Creators should assume more responsibility for their content's quality.


Edited by havasman, 27 October 2021 - 03:28 PM.

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#4 sevenofnine

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Posted 27 October 2021 - 07:08 PM

Good job! Nicely presented and you included ALL of the steps from beginning to end. Some instructions on You Tube start with the mirror out assuming you know how to remove it carefully. Then they omit the reinstalling it into the telescope plus the necessary collimation. My only nit-pic is using Dust-Off or any canned air on the primary. I used this stuff professionally for over a decade and it's just not reliable. The propellent is the devil to get off. Very possibly ruining delicate lens coatings or mirrors. A large Giotto Rocket Blower bulb is much better. waytogo.gif



#5 sunrag

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Posted 27 October 2021 - 07:32 PM

I have cleaned the mirror in my 8” three times in two years.

The first time I cleaned, the final rinse water (distilled) just beaded off the surface and rolled off easily. There were hardly any drops left to dry.

By the third time, the water drops were noticeably slow in rolling off. I had to use the tip of a paper towel to absorb the drops. So something is changing after each cleaning, causing water to stick more.


Edited by sunrag, 27 October 2021 - 07:33 PM.


#6 JJDreese

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Posted 27 October 2021 - 10:18 PM

Nice video. What do you use for video editing? I'm just getting started with making an instructional video.

Thank you. I use Camtasia for the editing. It runs slow on my old computer, but it does a good job.


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#7 JJDreese

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Posted 27 October 2021 - 10:21 PM

I have cleaned the mirror in my 8” three times in two years.

The first time I cleaned, the final rinse water (distilled) just beaded off the surface and rolled off easily. There were hardly any drops left to dry.

By the third time, the water drops were noticeably slow in rolling off. I had to use the tip of a paper towel to absorb the drops. So something is changing after each cleaning, causing water to stick more.

Thank you for that. It may very well be true that they can only handle so many cleanings.  Unfortunately, I can't remember how it was the last time I cleaned it. I rarely ever clean them though.



#8 JJDreese

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Posted 27 October 2021 - 10:26 PM

Good job! Nicely presented and you included ALL of the steps from beginning to end. Some instructions on You Tube start with the mirror out assuming you know how to remove it carefully. Then they omit the reinstalling it into the telescope plus the necessary collimation. My only nit-pic is using Dust-Off or any canned air on the primary. I used this stuff professionally for over a decade and it's just not reliable. The propellent is the devil to get off. Very possibly ruining delicate lens coatings or mirrors. A large Giotto Rocket Blower bulb is much better. waytogo.gif

Thank you. I'm glad you found it useful. I tried to be very thorough because I know the Orion XT8 is very common and including all the steps would help a lot of people.  As for the canned air, I try to be very careful.  For example, I never tilt the can because sub-freezing liquid comes spraying out.  And I try to keep it far away to minimize the blast.  For most optics, I use a glasses cleaning cloth.



#9 JJDreese

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Posted 27 October 2021 - 10:31 PM

https://www.youtube....h?v=9Y8xFnXFVGQ

 

This method is usually considered superior to the older cotton balls method. 

 

"Here is the most important thing about coatings - the enemy of a coating is moisture, in the form of liquid water and humidity.

Think of it this way - whenever moisture is in contact with the coating of your mirror, the clock is ticking.  There is only a finite time that the coating will stay undamaged when in contact with water, so it is best to minimize the time that the mirror is wet or is in very wet surroundings."  - Mike Lockwood from his website Loptics.com article Cleaning your mirror, and prolonging coating life which is found here -  http://www.loptics.c...mirrorcare.html

 

My recommendation for improvement is presenting the best available methods. Form is less important than content.

 

Sadly, youtube has become primary source reference for astro newbs. It is extremely common for misinformation to be spread this way. Creators should assume more responsibility for their content's quality.

There are indeed a lot of videos about cleaning.  I based my video on the official method from the Orion XT user manual.  I figured I could trust Orion, but I'm also open to other effective cleaning methods. There's always room for improvement.


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#10 Jon Isaacs

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Posted 28 October 2021 - 05:10 AM

There are indeed a lot of videos about cleaning.  I based my video on the official method from the Orion XT user manual.  I figured I could trust Orion, but I'm also open to other effective cleaning methods. There's always room for improvement.

Many of us here use the "Owl" method of cleaning our mirrors.  The basic idea is that you first rinse the mirror to clean off the dust.  Then a small bit of soap and you use your fingertips to lightly massage the mirror has underwater or has water standing on the surface.  You then rinse it and let it dry.

 

Until about 8 or 9 years ago, I used the cottonball method but the mirrors never came really clean.  When I switched to the OWL method, I was able to get dirty mirrors really clean.  The idea behind using your finger tips is that your fingertips are very soft and very sensitive so you can use very light pressure and feel any grit or foreign object.  With cotton balls,you really have no feel.

 

OWL stands for Optical Wave Laboratories.. They coat mirrors, refigure mirrors and make mirrors.  Here's the video:

 

https://youtu.be/9Y8xFnXFVGQ

 

Jon


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#11 vtornado

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Posted 28 October 2021 - 08:43 AM

For stuff that will not come off with a blower, I put the mirror into

a tupperware box fill the box with water add a few drops of detergent

and rock the box back and forth.  There are boxes big enough

to hold a cake.  A cat litter pan is also large enough. The agitation removes slightly

stuck on dust and spots.  However sometimes there is still stuff

on the mirror surface, then I use my finger tip.

 

One caveat is if your mirror has a clamshell chip, micro pieces of glass

can flake off at the clam site.  They are small enough to be suspended in

the water.  be  careful not to drag them across the surface of your mirror.

 

Rinse with distilled water, hold on edge for awhile to let the water drain off.

set the mirror down on an angle, and chase any water drops off with 

a squeeze bulb.


Edited by vtornado, 28 October 2021 - 08:44 AM.

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#12 Keith Rivich

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Posted 30 October 2021 - 07:00 PM

My heart skipped a beat when the OP turned the scope upside down to pull the mirror cell out. Putting lots of faith in the mirror clips!


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#13 JJDreese

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Posted 02 November 2021 - 10:02 AM

My heart skipped a beat when the OP turned the scope upside down to pull the mirror cell out. Putting lots of faith in the mirror clips!

Those clips are pretty strong. If they can't hold the mirror, then I've got bigger problems, lol.  :)


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#14 havasman

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Posted 02 November 2021 - 10:24 AM

There are indeed a lot of videos about cleaning.  I based my video on the official method from the Orion XT user manual.  I figured I could trust Orion, but I'm also open to other effective cleaning methods. There's always room for improvement.

Orion is a large enough entity to move more slowly than the speed of innovation. Their method is outdated and potentially destructive. The OWL method referenced above is the current best in class method.

 

One of many problems with youtube instructional videos is their permanence and intransigence while everything changes around them. They'd be better if, like the tapes from the old spy show, they'd self destruct soon.


Edited by havasman, 02 November 2021 - 10:26 AM.


#15 BoldAxis1967

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Posted 02 November 2021 - 11:06 AM

I also use the OWL method.

 

For removing the primary mirror I place the entire optical tube accessory (odd name) on my bed.  I find this horizontal position easier and less stressful than removing the primary and if need be the secondary mirrors with the optical tube in the dob mount.  I use pillows to prop-up as well as rotate the tube to gain access to different parts of the optical tube.

 

L.


Edited by BoldAxis1967, 02 November 2021 - 11:14 AM.


#16 leonard

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Posted 02 November 2021 - 01:47 PM

  - Mike Lockwood from his website Loptics.com article Cleaning your mirror, and prolonging coating life which is found here -  http://www.loptics.c...mirrorcare.html

 

Sadly, youtube has become primary source reference for astro newbs. It is extremely common for misinformation to be spread this way. Creators should assume more responsibility for their content's quality.

          Hello ,

 

                  Yes by all means follow the advice of opticians in the business , it’s there job not a hobby .

                   I have used the OWL method twice but like what I am reading on Lockwood website , a much

                   deeper dive into cleaning .

 

                         By all means leave YouTube to things like planting flowers and trees . Week end warriors with

                        a video camera can be a menace to society.


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