Anyone know if pst etalons can be fixed?

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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

Yeah, the slivers are pretty small, roughly 2mm-3mm across.
If the surfaces of the plates and the spacers are perfectly flat and perfectly clean they will "click" together under slight pressure.
That's what the theory says - no glue, no moisture, no dust nothing.....


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

What about tuning or turning it? Is there a special way they must be oriented against the other?


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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

Suffice it to say - You are not the first person here to decontact an etalon. We were keeping a running tally in the mods section or a while.

Can I suggest we move this post to the mods section so it don't get lost in the posing melee. There will always be good information that comes out in a post/conversation like this that will help other modders and unfortunates.

I have already marked it as a fav. Examples of issues we run into can only serve to help others in the future; especially if you succeed in recontacting the etalon.


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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

You should see marks on the etalons indicating direction. I think Mark T has identifide the orientation in the past.


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Ok how do we move it??


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

The marks dont really tell you anything more than light direction. Everything is marked like a V7 type mark. But they dont line up as in tuning


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Re: Anyone know if pst etalons can be fixed?

Post by solarchat »

Moved


Stephen W. Ramsden
Atlanta, GA USA
Founder/Director Charlie Bates Solar Astronomy Project
http://www.solarastronomy.org
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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

Stephen will see and do it, Have faith in the server god!


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Ok. Well it started as a question on repair now mod based... So I dont think I screwed up! :lol:


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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

SEE!!!! :lol: :cheer:


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Hahahahaha damn hes fast! :bow:


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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

Rob, you didn't foul up :? not the thread anyway :lol:. What your doing is important and not isolated. If sombody figures out how to do it - that person helps a whole commmunity! At least thats somthing to be happy about. ;)


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Now im determined to get this right!

Martha..... Get the crazy glue! :woohoo: :whistle:


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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

:lol:


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

Rob,
the critical aspect is not as much the radial alignment between the plates (they should be 1/100 wave all over, with no effect on tuning...) but to get the mirrored sufaces on the inside (ie at the air gap)
This is usually easy to see as this is the surface that has (or had) the spacers...
You can ONLY tune an etalon by changing the effective spacing (as detailed above)


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Ok. I think.... Lol

My plates have a total of 3 and a bit spacers. No mark on the sides that came off! So I guess I line up the etalon coatings so that they cover one another as closely as possible. Then try and get the darm thing to stick? Hahahaha yeah ok. I couldnt see the fringe lines on the pads. I did see them on the disks when I was holding them together. And I was able to get them running straight and parallel instead of bullseye.


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

I need acetone. The reagant i have didnt work.


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

I had to order from the Chemist..."Acetone" -Technical grade
Ohh and you'll need a clean room ;-)


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Hahahahaha so the garage wont cut it? :pinch:


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Those are cool.... Now im building a thing to put in my new clean room thing to recontact my separated thing? :S


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

Interestingly, if you use the etalon designer on the LightMachinery page
http://www.lightmachinery.com/etalon-designer-r8.php

You can see an etalon with 0.183mm thick spacers can give a bandwidth of 0.53A centred on 6563A and FSR 8A and a finesse of 14.8...sounds similar to ours...


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Or build the 60mm into the 127 for luntmod


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

This write-up may help explain the "workings" of an etalon...
(I'm on trial#6 or #7 in re-contacting an SM40 etalon...I can get one or two of the spacers to bond but not all five of them at the same time...)

Attached files Etalons_TechNote.pdf (319.5 KB)


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Re: Anyone know if pst etalons can be fixed?

Post by BelOptik_Oliver »

Hi etalonfriends,
I have already successful repaired an PST etalon with his four spacers and an Solarmax 40 front unit with new spacers.

You need follows working tools:
- pure alcohol or "Sidolin" window cleaner (streak free)
- wooden toothpick
- polishing cloth (100% cotton, clean and soft)
- thin tissue paper
- normal copy paper
- black base for working (Velour black)

1. Mark the correct position the plates to each other (if doesn't exist)
2. Clean the etalon plates with alcohol and please leave fixed spacer stay tuned.
2.2 Loose spacers please very careful clean by ligthly press with the cloth.
3. If all cleaned, place the etalon plate with the least number fixed spacer down on base and then drip little alcohol on etalon (up to surface is thin full covered).
4. Cut a tissue paper stripes and place on full etalon surface.
5. Put the second plate slightly on correct position on the tissue paper and pull out this paper.
6. Observe the optical contacting process on spacers - light color from white to black.
If doesn't contacted spacer, you see rainbow colors (Newton fringe).
7. When both etalon plates are full contaced with all spacers, then pull or slide copy paper stripes between the plates to absorb the rest of alcohol.

Loose spacers must contact individually with same process. For correct placing on thin alcohol film or tissue paper stripes, helps the toothpick.

As new spacers, I have used precise quartz waveplates with around 0.19...0.23mm thickness. Crushed by press makes some spacers. ;)

Btw, I have repaired the etalons in my kitchen on kitchen table. B)

If I have more time, I will make add. photos to some steps.


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Re: Anyone know if pst etalons can be fixed?

Post by JohnM »

I've never had the bad luck to wreck an etalon --- yet.
But I've got some experience with cheap clean rooms, I used to build bamboo fly rods and the finish was a classic dipped spar varnish which is an absolute dust magnet.
My "clean" room was just cheap plastic stapled to the ceiling and hanging to the floor with an overlapping slit to walk in.
Before each varnishing operation we would carefully mist the inside with a spray bottle of water, top to bottom, everywhere; let the settling mist carry the dust to the floor, then repeat.
We'd also wear clothes that weren't dusty and move as slowly as possible to not stir up any more dust, especially as the sections were drawn from the dip tube.

As far as recontacting the etalon halves, has anyone tried assembling the parts, then applying a drop of distilled water that would seep between the parts by capillary action and then drying it with a heat gun or such?


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Thanks guys. Some really good plans coming together here. Im going to try them all


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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

Hi, it is my understandng that water is the method used to seperate the spacers not recontact them. Oliver does this suff for a living, I would go with his advice.


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Re: Anyone know if pst etalons can be fixed?

Post by JohnM »

I know that, that's why I think a drop of water would allow correct positioning of the halves and on evaporation might allow the bonding to take place.
Just a thought really, from my experiences seeing highly polished parts seeming to get glued together after being damp and allowed to dry while in contact.


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

I picked up some acetone and a bottle of 99% isopropyl alcohol. That all I can find. Which do you think is better for the re-contact effort?


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

I've been using the Acetone for my attempts at repair....


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Re: Anyone know if pst etalons can be fixed?

Post by SolarJohn »

Rob - There is a person in Ontario that may be able to help you-eh. His name is Vaz Zastera of ZARTWERKS Studio in Merrickville, Ont-eh. A while back he had a video showing how optical contacting works, and I thought that I'd seen it on this forum-eh. He is a sculptor not an astronomer, but he may be able to help with your etalon-eh.
His website is http://www.zartwerks.com/ and a video about optical contacting is available on his site or youtube at http://www.youtube.com/watch?v=8nejla9u ... bedded#t=0 . Again, this is NOT the video that I had seen of him optically contacting glass-eh. I have that other video and would have attached it here, but it is about 24 MB big and too large to be uploaded to this site-eh.

He uses methanol to clean the glass and about a full box of lens tissue-eh. The video is worth seeing even though it is not an etalon contacting-eh. I'll search for a while to see where it might be archived and let you know-eh.
Too bad this site has small file restrictions-eh.

SolarJohn


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Re: Anyone know if pst etalons can be fixed?

Post by SolarJohn »

Rob - Found that video on Vimeo


http://vimeo.com/6654588


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

Now THAT was a video worth watching!!!
Love it!


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Re: Anyone know if pst etalons can be fixed?

Post by JohnM »

That is super interesting, thanks. :)
So, the cleaning has to be absolute!
To get 2 pieces of glass polished so one will float over another on trapped air is amazing and has to be where the time and skill comes in.

Now I have another question. I wonder if the air spaced etalons we deal with are only bonded at the slivers providing the separation?
Could that help explain how pressure applied to the etalon changes its tuning?
The plates are flexing on the bonded support pieces?


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

John,
Note that no pressure was used to get the bond..as the "gap" diminished (due to the evaporating spirit?) they just did their thing.

IMHO the etalon plates are far too thick to flex -under the loadings we can apply.
We don't know how...yet....but the spacers appear to "give" under applied pressure and change the tuning....white man's majic??!!


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

The direct question was asked regards the PST etalon....
QUOTE
I do not believe that there is a patent on the tuning of the PST. At least I did not help write one while I was at Coronado.

The etalon is tuned via mechanical compression (squeezing) and not tilt. It is a similar concept to the current RichView tuning system.

Best Regards,

Andrew Lunt CEO
UNQUOTE


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

A foam disk/small foam block at one side and an 'O' ring at the other.......


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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

Hi etalonfriends,
I have already successful repaired an PST etalon with his four spacers and an Solarmax 40 front unit with new spacers.

You need follows working tools:
- pure alcohol or "Sidolin" window cleaner (streak free)
- wooden toothpick
- polishing cloth (100% cotton, clean and soft)
- thin tissue paper
- normal copy paper
- black base for working (Velour black)

1. Mark the correct position the plates to each other (if doesn't exist)
2. Clean the etalon plates with alcohol and please leave fixed spacer stay tuned.
2.2 Loose spacers please very careful clean by ligthly press with the cloth.
3. If all cleaned, place the etalon plate with the least number fixed spacer down on base and then drip little alcohol on etalon (up to surface is thin full covered).
4. Cut a tissue paper stripes and place on full etalon surface.
5. Put the second plate slightly on correct position on the tissue paper and pull out this paper.
6. Observe the optical contacting process on spacers - light color from white to black.
If doesn't contacted spacer, you see rainbow colors (Newton fringe).
7. When both etalon plates are full contaced with all spacers, then pull or slide copy paper stripes between the plates to absorb the rest of alcohol.

Loose spacers must contact individually with same process. For correct placing on thin alcohol film or tissue paper stripes, helps the toothpick.

As new spacers, I have used precise quartz waveplates with around 0.19...0.23mm thickness. Crushed by press makes some spacers. ;)

Btw, I have repaired the etalons in my kitchen on kitchen table. B)

If I have more time, I will make add. photos to some steps.

I will be one who adds karma points for your assistance. Thanks


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

I will too if it works!

But what do I care.... I only have 5 :ohmy: HahahahahahahHHHA :whistle:


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Just got in from a very long day at work....been reading emails as they came in...but its 2:45am and I need sleep. Thanks for all the great responses! I cant wait to try them and see the videos! Many thanks for all of that stuff!
1 more night shift to go so I apologize for late responses in advance! :bow:


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

That is a great video! About 100 bucks in tissue...... But a really great tutorial! :bow: thanks for that!


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Re: Anyone know if pst etalons can be fixed?

Post by Allcart »

That was a very interesting video. So the cleaning has to meticulous, can you imagine how you are going to do that with those tiny spacers. :ohmy: You can barely see them, let alone clean them.

John; I wouldn't worry about how the tuning is done, it will do your head in.


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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

Here ya go Rob - Make it 6! Just for reviving the conversation. :lol:


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

:bow: :bow: :bow: Wooohooooo pity karma! :woohoo: :hamster: :hamster:

Lol just kidding. Its for the etalon.... :lol:


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Re: Anyone know if pst etalons can be fixed?

Post by sullij1 »

:lol:


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Re: Anyone know if pst etalons can be fixed?

Post by Merlin66 »

Gee, that's an old message - from the archives when Colin and I were learning our way....


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Re: Anyone know if pst etalons can be fixed?

Post by swisswalter »

Hi all

what a great thread. I'm on the way in my lab and I will run a scan on a spacer, then we will now its composition


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Thanks for that info Walter! Im going to attempt contact again today.... Its sunny but cold here so ill play with flammables inside instead of freezables outside today! :lol:


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Re: Anyone know if pst etalons can be fixed?

Post by RobBower »

Please see update called "Contact" its worth a look


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