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PostPosted: Wed Jan 09, 2019 4:08 pm 
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I bought my first microscope a couple of days ago, I was checking a couple of new cheap ones but they are overall still above the budget I had set, so I ended up buying an used one.
It's an old Carl Zeiss microscope that came from a lab that closed and auctioned its assets, it was bought from a guy that was interested in other machinery but had to buy the whole lot. It's a risk buying used when I don't know a lot about the field, but it was reasonably priced (225 euros) for something from a reputable manufacturer and it looked that it was used but looked after properly.

Here it is:
ImageImage

It is marked with "West Germany", so can I assume it was built before 1990? The 10x eyepieces look a bit worn on the outside, but they have zero scratches and the anti-reflective coating is spotless. What does the 1,25x marking mean, that there is an additional magnification other than the eyepieces? The stage looks very worn (and it is) but it appears to have been carefully maintained, it is still clean, properly greased and there is no "play", everything feels tight with the right amount of resistance to movement.

It came with two "older looking" 10x and 40x objectives, they look worn but the lens are clear and the images are not hazy, they are also all spring-loaded, which is nice on the larger magnifications, I remember breaking a couple of slides in school because I got lost while focusing and was too lazy to start-over:
Image

The 100x objective is also from Zeiss but it looks aesthetically different, it is marked NEOFLUAR 100/1.30 Oel, the front lens looks clear and I can focus with it but the images are a bit blurry, I assume it is because of the lack of immersion oil, which I didn't yet buy, so I didn't have the opportunity to test it adequately:
Image

My first doubt is this one, it also came with a Nikon objective in a Nikon cup:
Image

It doesn't feel as sharp as the 40x but I might not be using the adjustment collar properly. I didn't really find a lot of information about it, can someone give me an idea of it's value? It is in pristine cosmetic condition, if it's worth something I will try and sell it to buy more supplies, similarly named objectives seem to be worth something, the lack of information might mean it is an older model or that it is not very good and people are not looking for it.


The second doubt is this part that came in a wooden box:
Image

The domed mirror underneath makes me believe this is some sort of darkfield condenser, but I'm not entirely sure, I've tried to use it instead of the default condenser and the resulting images look really dim, although I didn't use any colorants.


The last item I'm not sure of it's purpose, the name suggests blue but it looks more neutral than blue, it kind of reminds me of a neutral density filter, but it is marked 1,0 and is way more dark than a photography ND1 filter:
Image


So, here are the organized questions:
What does the 1,25x marking in the head mean, that a 40x objective with the 10x eyepiece end up being 500x?
Is the Nikon objective worth anything?
Is that device in the box a darkfield condenser?
What is the purpose of the filter (aprox. 32mm diameter)?

Regards, and here is a bonus picture of my blood taken with my phone held directly in front of the eyepiece (not stained, as I don't yet have colourants):
Image


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PostPosted: Wed Jan 09, 2019 5:05 pm 
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Congrats on your 'first hobby microscope', Jose'. I have the Nikon Labophot microscope with a collection of Nikon objective lens optics. If your Nikon Plan-Apo 60X correction-collar objective is in good to excellent performance condition..then it is a valuable objective...both price wise, and performance wise. The need for you to understand if this objective is in proper performance condition..is to try it out with some test object...could be diatoms on a prepared slide.

You need setup the light source, the substage condenser, and patiently try out all your microscopes objectives. Get a comfortable bench and comfortable chair for your microscopy observing.

I do not know if Nikon plan-apo 60X objective is optimally compatible with your Zeiss microscope...others in forum will comment on this matter. But if that Nikon objective you have is in proper optical performance condition...it is a valuable objective. Charlie Guevara, finger lakes/US


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PostPosted: Wed Jan 09, 2019 6:43 pm 
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Congrats on a very good scope! That Nikon objective is a very fine bonus for sure. My guess is that your objective belongs to the Nikon CF series. However, I haven't seen that exact one before. The Nikon 160mm CF series went through a couple of design changes. The last one can be seen in this catalogue: http://www.krebsmicro.com/Nikon_CF

The later version of the 60x plan Apo dry objective in the catalogue has a bit higher resolution, 0.95 vs 0.90 for your objective.

The Nikon objective, however, is not going to play well with your Zeiss optics, though. The Zeiss system has quite a lot of color correction in the eyepieces, while the Nikon CF objectives are fully corrected on their own, and the eyepieces are 'neutral' so to say. So the corrections made by your Zeiss eyepieces will mess things up.

If you decide to sell it I would definitely be interested!


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PostPosted: Wed Jan 09, 2019 7:57 pm 
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viktor j nilsson wrote:
The Nikon objective, however, is not going to play well with your Zeiss optics, though. The Zeiss system has quite a lot of color correction in the eyepieces, while the Nikon CF objectives are fully corrected on their own, and the eyepieces are 'neutral' so to say. So the corrections made by your Zeiss eyepieces will mess things up.
I got that impression in this forum, people were alerting users wanting to upgrade objectives that in some cases the eyepieces should be also upgraded to a specific family for optimum results. It works, but is a bit soft, I've tried to mess with the collar and the focus but it never quite gets "there" like the 40x does, there is also a significant chance that I might not have the knowledge to use it to it's full capacities.

Regarding this color correction issue, should I be worried about this even with Zeiss objectives or are 160mm Zeiss more or less interchangeable in my case? (Also, remember that I just want to have fun, I am not taking pictures to publish papers, I don't need perfection).

viktor j nilsson wrote:
If you decide to sell it I would definitely be interested!
Sure, I was asking you guys to know a ballpark number to ask on eBay. It might sound weird but having a (hopefully) working 100x, I am more interested in a 4x objective than the 60x, but if you know it's value and it isn't against the forum rules send me an offer via PM with a number that is fair for both of us.


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PostPosted: Wed Jan 09, 2019 7:59 pm 
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yes that Nikon plan apo objective is quite nice when paired with the correct eyepieces. I wouldn't mind owning it either..:)


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PostPosted: Wed Jan 09, 2019 8:27 pm 
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As long as you stay with optics branded Zeiss or Zeiss West, and not the considerably older Zeiss Jena, you probably don't need to worry about any mismatch. But others here are more knowledgeable about the Zeiss system than me.

I don't have a 4x, but I do have a nice Zeiss Plan 2.5x and a Zeiss Plan 16x objective lying around that you might have better use for than I do? I'll send you a PM and we can talk!


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PostPosted: Wed Jan 09, 2019 9:31 pm 
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Hi José,
you bought a verry nice microscope there. It is a Zeiss Standard from western Germany, 160mm tube length, all original objectives calculated to be used with correction eyepieces. Your eyepieces and the black achromatic objectives and the silver Neofluar match perfectly. The black achromats are not old and quite nice for achromats. With Zeiss you have to know the difference between West and Jena - some parts work together, some not. With the Nikon you should look for blue and yellow colour fringes at the border of a contrasty object. This would indicate a mismatch between eyepieces and objective. A Plan Apo is the highest correction class in microscope objectives, it would cost a couple to thousands new. It might be worth 200-300€ (very rough estimation). The correction collar is used to set the objective for the right cover slip thickness. It is a strong dry objective and they are sensible for too thick cover slips and too thick preparations, so the correction collar.
A dry 60:1 is a nice addition so I would keep it at the moment, if funds allow. You always get the best image with the weakest objectives, especially when the preparation of the object is not too good. So give the 60:1 a chance, you might no be able to see it's quality as a newbie. If it doesn't match your eyepieces, it will be easy to get too fitting eyeieces for it.
You might have a closer look at your objectives and eyepieces: Zeiss West optics tend a bit more to delamination, break down of glues inside lens groups. Do you have a stereo microscope or a phase telescope?

Does the dark field condenser fit to your condenser holder?

Bob


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PostPosted: Wed Jan 09, 2019 9:44 pm 
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Yes, that microscope head provides additional 1.25x magnification.

The Nikon plan apo 60/0.9 is a valuable objective, but you need to match correction collar with actual cover thickness (many times it may not be exactly 0.17mm; at dry NA of 0.9, there is not much room for error). To get the best from it, you would need Nikon eyepiece (probably CFW10).

Yes, that is a darkfield oil immersion condenser, which has to be used with oil immersed onto bottom of microscope slide.


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PostPosted: Wed Jan 09, 2019 11:19 pm 
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MicroBob wrote:
You might have a closer look at your objectives and eyepieces: Zeiss West optics tend a bit more to delamination, break down of glues inside lens groups.

Can I do something about it preemptively, or is this a sort of "it happens" deal? Didn't knew they used adhesives inside, the vintage (camera) lens that I've serviced used inner rings and spacers to hold everything together, maybe microscope objectives require tighter tolerances and individual adjustments during the assembly.

MicroBob wrote:
Do you have a stereo microscope or a phase telescope?

I assumed it's a regular stereo microscope, it looks to me like a regular condenser.
This is the holder, there is an iris ring in the light output at the bottom and a condenser holder, the 2 screws and the spring look like it is designed to hold flanges:
Image

This is the condenser that came installed, and is held in place by the bottom flange:
Image

MicroBob wrote:
Does the dark field condenser fit to your condenser holder?

The metal collar around the dark field condenser looks like it is designed to be mounted on a different structure, and now that zzffnn tells me it is designed to be used with oil on top it is way too short to be mounted on the holder and touch the slide (if I just rest it on top of that holder and move the holder to the uppermost position it still sits several millimetres below the slide):
Image

The guy just told me it belonged to the lot where the microscope came from, it didn't come with any documentation, just this fancy box:
Image


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PostPosted: Wed Jan 09, 2019 11:29 pm 
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I echo MicroBob's advice … hang onto the Nikon CF 60x plan apo for a while. It's a big magnification jump from 40x to 100x. Depending upon what you study, you may find the "in-between" 60x to be ideal for many observations. If not, you can sell it and buy something that works better with the Zeiss oculars.

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PostPosted: Thu Jan 10, 2019 9:11 am 
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Hi José,

cemented lens groups are used to reduce the number of glass-air surfaces where light loss and stray light is produced. They are necessary for high performance optics. I try a little to keep my microscopes from quick temperature changes and avoid hard knocks on the objective barrels.

You have a binocular compound microscope, not a stereo microscope. Stereo microscopes have separate imaging for left and right and allow stereoscopic view at low magnification of 10x to 40x usually.
The delaminations are within the stack of lenses and you can detect it by focussing through the height of this stack in transmitted light. Delaminations often start at the border and work their way to the middle. In some cases they have a strong impact on image quality, in some cases not. There also have been successful repair attempts with Canadabalsam or immersion oil.

Your dark field condenser has a collar to be mounted on older Zeiss microscopes. If you can raise it to the right height and center it there properly, you might be able to use it. Dark field condensers for the Zeiss Standard are not very common and not cheap, so it might be worth the try.

Bob


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PostPosted: Thu Jan 10, 2019 11:19 am 
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MicroBob wrote:
cemented lens groups are used to reduce the number of glass-air surfaces where light loss and stray light is produced. They are necessary for high performance optics. I try a little to keep my microscopes from quick temperature changes and avoid hard knocks on the objective barrels.
Oh, I see, so they are actually bound together with optical adhesive between them, now I get it, I thought the adhesive was on the sides to hold them together at the right distance. I was thinking "how hard can that be to repair?", but just removing the old adhesive must be awful, then making sure there are no bubbles in the new optical adhesive layer, no thank you...
Avoiding thermal and physical shock sounds like very good advice for any kind of optical system. My "lab" resembles a bunker, so at least I have temperature stability.

MicroBob wrote:
You have a binocular compound microscope, not a stereo microscope. Stereo microscopes have separate imaging for left and right and allow stereoscopic view at low magnification of 10x to 40x usually.
Thank you for the clarification. I'm actually in the process of finding a stereo microscope for very small electronics inspections and to aid in repairs of sub-mm pitch components, but in portuguese some of us actually use (and probably shouldn't) the name "binocular loupe" regarding both that stereo microscope arrangement and those dual loupes that you use in your head.

MicroBob wrote:
The delaminations are within the stack of lenses and you can detect it by focussing through the height of this stack in transmitted light. Delaminations often start at the border and work their way to the middle. In some cases they have a strong impact on image quality, in some cases not. There also have been successful repair attempts with Canadabalsam or immersion oil.
When I get the stereo microscope I will put them to the test, but looking at this website, http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/artaug06/dw-delam.html, I don't think mine are quite there yet.

MicroBob wrote:
Your dark field condenser has a collar to be mounted on older Zeiss microscopes. If you can raise it to the right height and center it there properly, you might be able to use it. Dark field condensers for the Zeiss Standard are not very common and not cheap, so it might be worth the try.
When I have the time for it I'll just take a couple of measurements from the holder and the condenser and improvise some sort of tube extension in the 3D printer.


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PostPosted: Thu Jan 10, 2019 12:43 pm 
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CocasDaNeve wrote:

MicroBob wrote:
Your dark field condenser has a collar to be mounted on older Zeiss microscopes. If you can raise it to the right height and center it there properly, you might be able to use it. Dark field condensers for the Zeiss Standard are not very common and not cheap, so it might be worth the try.
When I have the time for it I'll just take a couple of measurements from the holder and the condenser and improvise some sort of tube extension in the 3D printer.
Because they are rather rare it is important that you do not damage/permanently modify it in your attempt to get it to fit your microscope.
It might even make more sense to sell it and use the money towards another one or perhaps something else you need.

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PostPosted: Thu Jan 10, 2019 1:27 pm 
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75RR wrote:
CocasDaNeve wrote:

MicroBob wrote:
Your dark field condenser has a collar to be mounted on older Zeiss microscopes. If you can raise it to the right height and center it there properly, you might be able to use it. Dark field condensers for the Zeiss Standard are not very common and not cheap, so it might be worth the try.
When I have the time for it I'll just take a couple of measurements from the holder and the condenser and improvise some sort of tube extension in the 3D printer.
Because they are rather rare it is important that you do not damage/permanently modify it in your attempt to get it to fit your microscope.
It might even make more sense to sell it and use the money towards another one or perhaps something else you need.
Is this considered relatively rare? I thought the rare and expensive ones were the ones that fit in my microscope. I would not modify it, though, I would build a support that fit my condenser holder and something that fit the collar of the condenser, something like this:
Image

I saw a couple on eBay (just the lens, though, not the complete assembly) while trying to figure out it's applications, so I didn't think much of it. Maybe I'll put it on the buying and selling area of the forum to see if there's someone with a matching microscope interested in the part, it's probably something I will not be involved with in the near future.


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PostPosted: Thu Jan 10, 2019 1:33 pm 
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Not sure how rare. Here is one that sold recently that would fit your microscope.

https://www.ebay.com/itm/Carl-Zeiss-Ult ... 7675.l2557

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PostPosted: Thu Jan 10, 2019 1:51 pm 
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Well, the price is identical and it looks like the only difference is the lens holder. Still, rest assured I will not hit it with the Dremel :D .


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PostPosted: Thu Jan 10, 2019 2:38 pm 
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On the german used market newer dark field condensers (like Zeiss Standard ring dovetail mount) can be found much less frequently than older ones. The method was not used as much after the second word war and the introduction of phase contrast.

A dark field condenser has to be centered precisely so this has to be taken into account with the design of the adapter. You microscope offers centering screws on the condenser holder, you just have to make a dovetail and above a holder for the condenser.

It's great that you have a 3d printer, it can be used for lots of microscopy accessories. Cardboard and hot glue wouldn't help with the build of this adapter.


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PostPosted: Thu Jan 10, 2019 3:17 pm 
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Hello and congrats on your "new" microscope.. I see it as a very good source for a lifetime of enjoyment and a great hobby.. I wouldn't get in a hurry to condemn the Nikon objective with the correction collar... These are almost perfect and the design is flawless... It may work out perfectly for you as a "hobby" user.. Sometimes a hobby user is not as critical as a person that does this stuff for a living... A slight color difference usually means very little to the hobby person.. Hobby folks just want to see things.. A 99% perfection is not needed.. Here is a link that may explain a lot about microscope objectives.. It is a tour de force on the subject..

https://www.edmundoptics.com/resources/ ... bjectives/

Regards,
BillT


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PostPosted: Thu Jan 10, 2019 3:38 pm 
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I would keep the darkfield condenser. If in working condition, it is supposed to yield high quality darkfield since it is based on reflective mirrors and not lenses. It will provide DF with high NA objectives. Above NA of 1.0.

Your question about the blauklar filter: The mark "1,0" could mean that its absorbance (optical density) is 1.0 so transmittance is 10%. However an ND1 mark means exactly the same, so if the blaufilter looks much darker, the meaning of 1,0 remains unknown. A neutral density filter is normally grey, not blue. But, perhaps this is a combination - a neutral density filter that serves for photography as well - removes red light. It might also be a fluorescence (excitation) filter, possibly an old bandpass filter (based on light absorption) but its diameter of 32 mm fits the illumination field iris or the under-condenser rack, both are not related to epi-fluorescence. No definitive answer regretfully...

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PostPosted: Thu Jan 10, 2019 6:27 pm 
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The filter and case most likely don't belong together
Here's seemingly identical filter described as a Wild Heerbrugg M20 neutral density filter.

https://www.ebay.com/itm/WILD-HEERBRUGG-SWISS-M20-1-0-ND-NEUTRAL-FILTER-MICROSCOPE-PART-OPTICS-33-B-04/153302771381

But I agree it looks very very dark!


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PostPosted: Sat Jan 12, 2019 2:51 pm 
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I was curious to try it out, so yesterday I designed a simple adaptor that could be mounted on my condenser holder and that could grab the collar of the darkfield condenser, then I sent it to the printer during the night. This is what I ended up with:
Image

This is what it looks like mounted on the microscope:
Image

I don't have immersion oil yet, but I reckoned water should have some effect, so I took another blood sample, put a small drop of water on the condenser glass and moved it up until the water was touching both the condenser and the glass slide:
Image

And I guess it works! The photo was taken with a phone behind the eyepiece:
Image


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PostPosted: Sat Jan 12, 2019 3:06 pm 
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Very cool looking project! Those 3D printers can be handy...

If you can locally find castor oil or glycerin, those have a higher index of refraction than water, and closer to immersion oil. Some folks use these products instead of immersion oil for routine purposes, and they work fine. Both have a high viscosity, which helps with the condenser to bottom of slide connection.

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A/O 10 Series Microstar
A/O 4 Series Microstar
A/O 4 Series Phasestar
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A/O Cycloptic Stereo
Several old monocular scopes in more or less decrepit but usable condition


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PostPosted: Sat Jan 12, 2019 3:29 pm 
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Ditto desertrat above... Castor oil works fine...

BillT


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PostPosted: Sat Jan 12, 2019 3:30 pm 
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Quote:
I was curious to try it out, so yesterday I designed a simple adaptor that could be mounted on my condenser holder and that could grab the collar of the darkfield condenser, then I sent it to the printer during the night. This is what I ended up with:

I am guessing this nice darkfield photo was taken with the Nikon 60X objective? would be interesting to see ot woth the 100X/1.30 oil.

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Last edited by Hobbyst46 on Sat Jan 12, 2019 4:47 pm, edited 1 time in total.

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PostPosted: Sat Jan 12, 2019 4:09 pm 
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I agree.. The dark field photo is very good..

BillT


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PostPosted: Sat Jan 12, 2019 5:10 pm 
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Like your darkfield condenser holder, and as you said not a Dremel in sight!

Emergency immersion oil substitutes:

Image

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PostPosted: Sat Jan 12, 2019 5:14 pm 
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Just be careful with oil of wintergreen. Great smell but too much skin exposure or ingestion can be dangerous.


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PostPosted: Sat Jan 12, 2019 5:25 pm 
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Hi José,

good work - you designed a very nice adapter!

Bob


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PostPosted: Sat Jan 12, 2019 5:26 pm 
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I think the refractive index of wintergreen oil is a bit too high to make a good immersion fluid. Also, it's a very good solvent.

Tung oil is a fairly good match, but it dries by polymerizing in contact with air. If it's allowed to dry on an objective, it is impervious to most solvents.

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A/O 10 Series Microstar
A/O 4 Series Microstar
A/O 4 Series Phasestar
A/O 4 Series Apostar
A/O Cycloptic Stereo
Several old monocular scopes in more or less decrepit but usable condition


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PostPosted: Sat Jan 12, 2019 5:57 pm 
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desertrat wrote:
If you can locally find castor oil or glycerin, ... Both have a high viscosity, which helps with the condenser to bottom of slide connection.
A very good point. Most of the vegetable oils have refractive indices of 1.45-1.52 (except cinammon and casia oils whos RIs are 1.55-1.58, and besides they are excellent solvents); however, the viscosities of almost all vegetable oils fall within a narrow range, whereas the viscosity of castor oil is about 10 times as high.

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