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Equipment Discussions >> Reflectors

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jeff heck
Pooh-Bah
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Reged: 01/16/06

Loc: stl,mo.
mirror cleaning and cotton new
      #5637385 - 01/22/13 05:20 PM

Is there a preferred type or brand of cotton rolls when cleaning a mirror? I see various types; sterile, non sterile, bleached, absorbent, non absorbent, etc.
Also, I plan on using the method shown on the Lockwood website. Will using acetone or alcohol remove the hotspot?


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GeneT
Ely Kid
*****

Reged: 11/07/08

Loc: South Texas
Re: mirror cleaning and cotton new [Re: jeff heck]
      #5637457 - 01/22/13 05:57 PM

Sterile.

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cliff mygatt
Carpal Tunnel


Reged: 01/27/09

Loc: Kitsap County, WA
Re: mirror cleaning and cotton new [Re: GeneT]
      #5637727 - 01/22/13 08:52 PM

Sterile and make sure it is 100% cotton. I just cleaned my Zambuto mirror and it is all set for the season. Good Luck!

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Cames
sage


Reged: 08/04/08

Re: mirror cleaning and cotton new [Re: jeff heck]
      #5639058 - 01/23/13 03:02 PM

Jeff,
Acetone will dissolve the adhesive holding the center spot in place. Acetone may not entirely remove the spot if the contact time is short but you will almost instantly have a mixture of acetone and adhesive pooling on the coated mirror surface. The problem is that the acetone evaporates extremely quickly and when it does, it will have redeposited the adhesive on the coating where you don't want it to be.

If you are going to use acetone, be sure to have some soapy water ready to dilute and rinse away the acetone/adhesive mixture before any of the acetone evaporates. Once you have thoroughly washed away the 'adhesitone', complete the rinse and dry phases normally. This should prevent the adhesive haze that would otherwise appear. Good luck.

Presoak the cotton to soften it. Contacting the coating with dry or incompletely wetted cotton has a high probability of sleeking the coating.

Never use Q-tips and the like. In my experience, they scratch coatings like sandpaper.
--------
C


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jeff heck
Pooh-Bah
*****

Reged: 01/16/06

Loc: stl,mo.
Re: mirror cleaning and cotton new [Re: Cames]
      #5640687 - 01/24/13 01:25 PM

Thanks for the replies.
Cames, that is good information and has me leaning to using a soapy water mixture of Dawn or Dreft instead of the acetone or alcohol.


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gb_astro
sage


Reged: 01/01/08

Loc: Sydney, Australia
Re: mirror cleaning and cotton new [Re: jeff heck]
      #5641838 - 01/25/13 01:18 AM

Quote:

Thanks for the replies.
Cames, that is good information and has me leaning to using a soapy water mixture of Dawn or Dreft instead of the acetone or alcohol.




Jeff I assume you are removing the center spot for some other reason than the cleaning?

gb.


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jeff heck
Pooh-Bah
*****

Reged: 01/16/06

Loc: stl,mo.
Re: mirror cleaning and cotton [Re: gb_astro]
      #5642416 - 01/25/13 11:51 AM

I do want to keep the center spot on the mirror, that is why I will not use the chemical wash.
I had a hazy coating as well as cat hair and dust on my mirror. I suspect when the mirror dews up after bringing it in from the cold plays a role in this. I always turn the three fans on with the mirror cover off to get the moisture off of the mirror.
Anyway, I cleaned it using Dawn and a bag of cotton balls lightly dragged over the mirror but the balls only removed a thin line of the haze. I hope using a large cotton roll will remove all of the film.


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Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: mirror cleaning and cotton new [Re: jeff heck]
      #5643082 - 01/25/13 06:13 PM

I have the same problem with a build up of haze because my mirror is stored indoors and I believe fine dust from vacuum cleaner use coupled with cooking odors deposit a fine gray haze on the mirror.

I have found that soap does a good job of cleaning this off.

And, like the OWL Labs video on YouTube ( http://www.youtube.com/watch?v=9Y8xFnXFVGQ ) for cleaning a mirror in the sink, I found that cotton balls did not clean the mirror adequately, so I use my fingertips.
Place a folded towel in the bottom of the sink so the mirror won't sit directly on steel or porcelain. Place the mirror in the sink.
1) Holding the mirror at an angle, rinse the mirror with the tap sprayer until all the dust is washed off the mirror. Turn the mirror several times to get off pieces of junk that are stuck to the mirror.
2) place the mirror flat and fill up the concavity with tap water into which you squirt a little of the dishwashing foam, or pour in a dishwashing liquid/water mix you made in a bowl (one drop of liquid in a bowl creates a lot of foam). Make sure the dishwashing liquid is the el cheapo type, with no hand lotion, aloe, or expensive perfumes added.
3) using your fingertips, and making little circular motions, start at one side of the mirror and proceed across to the other. If you feel a piece of grit, stop immediately and rinse the mirror again with the tap sprayer and start the process all over again. A cotton ball would never feel the piece of grit and you would scratch the mirror.
Pass over the mirror in small strips from one side to the other. When you have done the entire mirror, rinse it.
4) look closely at the mirror. Is the haze gone? Then proceed to step 5. Otherwise, repeat steps 2 and 3 with the mirror turned 90 degrees from the first time. If one part of the mirror is shinier than the rest, then you haven't gotten all the haze off.
5) Rinse the mirror thoroughly with the tap water sprayer. Grab a gallon of distilled water (won't take more than this), hold the mirror at an angle and do the final rinse with distilled water, making sure you have rinsed the entire mirror a lot.
6) Remove the mirror from the sink, place it on a towel, leaning against the wall and let the leftover water drops evaporate (distilled water won't leave spots). When dry, put the mirror back in the scope.

When I tried to figure out what I could use to clean the mirror that wouldn't scratch the coating, and would not drag a piece of grit across the mirror, and could vary its pressure on the mirror surface delicately, nothing better than fingertips came to mind. I've been using the fingertips technique for years before I saw Cary's video. And they do a better and safer job than cotton balls at removing haze.


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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: mirror cleaning and cotton new [Re: Cames]
      #5643542 - 01/25/13 11:01 PM

Don't use cotton and acetone together. Use non-cotton disposable optical wipes if cleaning with acetone. Use sterilized cotton with distilled water and dish soap. I had a bad experience cleaning a mirror using sterilized cotton and acetone a few years ago. This combo left a brownish coloring on the mirror surface that wouldn't come off with water and soap. The acetone broke down the cotton and left a brownish-colored residue on the mirror. I phoned Roland Christen of A-P about this and he confirmed that the acetone was reacting with the cotton and leaving a residue on the mirror. He recommended re-cleaning with acetone but using non-cotton optical wipes. I repeated as instructed with acetone using A-P's optical wipes. It worked! Cotton is only safe with dish soap and distilled water mix and optionally alcohol added to the mix.

Quote:

Jeff,
Acetone will dissolve the adhesive holding the center spot in place. Acetone may not entirely remove the spot if the contact time is short but you will almost instantly have a mixture of acetone and adhesive pooling on the coated mirror surface. The problem is that the acetone evaporates extremely quickly and when it does, it will have redeposited the adhesive on the coating where you don't want it to be.

If you are going to use acetone, be sure to have some soapy water ready to dilute and rinse away the acetone/adhesive mixture before any of the acetone evaporates. Once you have thoroughly washed away the 'adhesitone', complete the rinse and dry phases normally. This should prevent the adhesive haze that would otherwise appear. Good luck.

Presoak the cotton to soften it. Contacting the coating with dry or incompletely wetted cotton has a high probability of sleeking the coating.

Never use Q-tips and the like. In my experience, they scratch coatings like sandpaper.
--------
C




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turtle86
Pooh-Bah Everywhere Else
*****

Reged: 10/09/06

Re: mirror cleaning and cotton new [Re: Peter Natscher]
      #5644681 - 01/26/13 04:25 PM

Great info on this thread. Didn't know about acetone and cotton not playing well together. I like to keep my mirror clean, but have found that after following the procedure in the Starmaster manual (which basically involves spray bottles, dish soap, distilled water and avoids touching the mirror), I can still see a faint haze.

I doubt that the slight haze on my mirror really makes a significant difference for most objects but it sure can't help things, and for challenge objects I need all the help I can get. At the same time I don't want to risk scratching the mirror or fuss with acetone residue so I've been giving some thought to using my fingertips too. Trouble is, my 18" mirror is too big for my sink. I've looked for something along the lines of a large drip pan, but haven't yet seen anything suitable.


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rockethead26
Post Laureate
*****

Reged: 10/21/09

Loc: Arizona, USA
Re: mirror cleaning and cotton new [Re: turtle86]
      #5644740 - 01/26/13 05:06 PM

Quote:

Trouble is, my 18" mirror is too big for my sink. I've looked for something along the lines of a large drip pan, but haven't yet seen anything suitable.




I use the tub for my 14.5". The sink is a little tight for me too.


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Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: mirror cleaning and cotton new [Re: turtle86]
      #5644796 - 01/26/13 05:39 PM

Quote:

Great info on this thread. Didn't know about acetone and cotton not playing well together. I like to keep my mirror clean, but have found that after following the procedure in the Starmaster manual (which basically involves spray bottles, dish soap, distilled water and avoids touching the mirror), I can still see a faint haze.

I doubt that the slight haze on my mirror really makes a significant difference for most objects but it sure can't help things, and for challenge objects I need all the help I can get. At the same time I don't want to risk scratching the mirror or fuss with acetone residue so I've been giving some thought to using my fingertips too. Trouble is, my 18" mirror is too big for my sink. I've looked for something along the lines of a large drip pan, but haven't yet seen anything suitable.



I used to use a large plastic storage box that was 24 x 30. But then I put in a new sink which will easily take an 18" mirror.
The haze definitely reduces brightness and reduces light grasp and scatters light.
Here is an article on mirror cleaning you need to read. When I hear about amateurs who haven't cleaned their mirrors in years, I am reminded of this article.
It's frightening how fast the reflectivity decreases when dirt is added.
Speed of reflectivity decline and effects of cleaning.


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turtle86
Pooh-Bah Everywhere Else
*****

Reged: 10/09/06

Re: mirror cleaning and cotton new [Re: Starman1]
      #5645991 - 01/27/13 12:42 PM

Though I've cleaned my mirror at least twice a year since I've owned it, and keep it in the mirror transport box when not in use, it does seem that the haze has gotten slightly worse over time. I really notice it whenever I shine a red light on my mirror to use my Catseye autocollimator at night. One of those large plastic storage boxes you mentioned should do the job.

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jeff heck
Pooh-Bah
*****

Reged: 01/16/06

Loc: stl,mo.
Re: mirror cleaning and cotton new [Re: turtle86]
      #5646247 - 01/27/13 03:16 PM

Thanks for the links, Don P. I have seen the handwashing video before and will be doing it later this week. I was not thrilled about dragging a large cotton toboggan over my primary. Don, do you totally submerge your mirror or do it like the video shows?
Turtle86, the red light while collimating is the same way I noticed my film/haze. After two attempts with cotton balls I got a "spoked wheel" effect with most of the haze still there.


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ScumotheUniverse
sage


Reged: 12/02/08

Loc: first dark primordial pool.
Re: mirror cleaning and cotton new [Re: jeff heck]
      #5646287 - 01/27/13 03:42 PM

Dave Kriege's method has worked well for me. http://www.obsessiontelescopes.com/learning_center/cleaning_mirror/index.php Also keeping an old well washed towel covering your mirror during storage will make cleaning far less neccesary.

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Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: mirror cleaning and cotton new [Re: jeff heck]
      #5646563 - 01/27/13 06:01 PM

Quote:

Thanks for the links, Don P. I have seen the handwashing video before and will be doing it later this week. I was not thrilled about dragging a large cotton toboggan over my primary. Don, do you totally submerge your mirror or do it like the video shows?
Turtle86, the red light while collimating is the same way I noticed my film/haze. After two attempts with cotton balls I got a "spoked wheel" effect with most of the haze still there.



I've done it both ways--submerged and just with the concavity filled. When the mirror is submerged, I think it's harder to have as strong a detergent mixture, though you could, I suppose. But simply filling the concavity allows rinsing and repeating as necessary without wasting a lot of water or detergent. I make a bowl filled with a mix of detergent and water and just pour it into the mirror. Sometimes I have to clean the mirror twice because I see hazy sections that didn't come clean after the first washing.
When I do the final rinse, the mirror is a lot shinier and obviously cleaner.
I'm currently rinsing the mirror with distilled water about every 2 months and washing it every four. But the noticeably cleaner and shinier nature to the coating after cleaning says i should clean it every 3 months.
I wish I knew the reason for the haze build up. It's probably very fine dust mixed with cooking odors in my house. I'm toying with the idea of storing the mirror in a sealed case in between outings to reduce the exposure to environmental junk, because it's becoming annoying.
Apparently, professional observatories notice the same thing, though, and they don't have smog or cooking odors to contend with.
So I just may be being picky about the appearance of the coating. Large dust particles are easy to rinse off, so I don't really concern myself with them. But the haze build up only comes off with water, detergent, and rubbing.


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Joad
Wordsmith
*****

Reged: 03/22/05

Re: mirror cleaning and cotton new [Re: Starman1]
      #5646576 - 01/27/13 06:09 PM

I know that reading the instructions for mirror cleaning once scared the heck out of me. But I've finally just done it (figured out at last how to remove my mirror from the Portaball), and with a solution of almost entirely distilled water with a drop of dish washing detergent and a bit of rubbing alcohol, I have very very gently dragged (not rubbed) some cotton across the surface and have gotten a very clean looking mirror with only a couple of droplet residue marks. Mirror (a Zambuto) looks great, and the job isn't as terrifying as some of the guides say it is.

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Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: mirror cleaning and cotton new [Re: Starman1]
      #5646621 - 01/27/13 06:28 PM Attachment (16 downloads)

I guess i'm fortunate... have seen no "haze" build up on my mirror; am probably a 2x-3x per year washer. When the scope gets left outside more, esp. since getting it a Telegizmos cover, i notice the fine dust builds up more quickly... so am prob'ly now closer to a 3x per year washer. Dish soap & soft-water, followed with an R.O. rinse. Seems to work well, the RO doesn't spot.

For storage, the scope lives in the house- as "furniture"... barely qualifying by management. The mirror itself is stored separately in a clear plastic storage box, acquired from O.S.H.- works wonderfully! Maybe is why i have no "haze" so far?


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Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: mirror cleaning and cotton new [Re: Joad]
      #5646623 - 01/27/13 06:28 PM

It's sort of like collimation--you're only afraid of it until you've done it and realized it wasn't all that hard or scary.
The mirror runs a bigger danger from chipping by hitting it against the sink, so there you do have to be careful (cleaning that is, not collimation ).


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Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: mirror cleaning and cotton new [Re: Mike B]
      #5646636 - 01/27/13 06:32 PM Attachment (13 downloads)

... then, due to management appeasement procedures, a LOT of my smaller astro-stuff resides in a cabinet originally designed to house the older-style big-screen TVs; we faced it with doors, and the mirror+box sleeps in there- so maybe i'm DOUBLY insulated from the usual contributors to indoor mirror contaminants.


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