DIY phase telescope / microscope collimation

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imkap
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DIY phase telescope / microscope collimation

#1 Post by imkap » Sat Jan 22, 2022 9:59 pm

Hi everyone,
I found this article and tried to make one myself.:
http://www.microscopy-uk.org.uk/mag/ind ... phase.html

I have connected 2 tubes of C8 eyepiece, using the provided focusing thread half way through both tubes (Don't know does this make sense without a pic) and put the optics of a focusable Zeiss Kpl 8x on both sides of the tube. I'm not sure it is working :D I don't really know what result should I get. When I put the eyepiece on the microscope without any optics between the eyepiece and the light I see a centered light circle. Not sure how this should work. Anyone did this?

I've seen an article on the same site about collimating a microscope, I figured by myself before reading this that it should all line up. So I would do this: I have an eyepiece with 2 concentric rectangles, so I would center the light source first by moving the arm, then the bino head etc. and last the flip-top condenser. I suppose this should be good enough at least for visual, but still I'd like to try to do it with a phase scope... Any help is aprreciated, thanks

Hobbyst46
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Re: DIY phase telescope / microscope collimation

#2 Post by Hobbyst46 » Sat Jan 22, 2022 11:32 pm

imkap wrote:
Sat Jan 22, 2022 9:59 pm
Hi everyone,
I found this article and tried to make one myself.:
http://www.microscopy-uk.org.uk/mag/ind ... phase.html

I have connected 2 tubes of C8 eyepiece, using the provided focusing thread half way through both tubes (Don't know does this make sense without a pic) and put the optics of a focusable Zeiss Kpl 8x on both sides of the tube. I'm not sure it is working :D I don't really know what result should I get.
For example, with the phase telescope you clearly and sharply see the condenser iris aperture (NOT the field aperture), try to open and close it and it shows in focus.

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imkap
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Re: DIY phase telescope / microscope collimation

#3 Post by imkap » Sun Jan 23, 2022 12:14 am

Hobbyst46 wrote:
Sat Jan 22, 2022 11:32 pm
For example, with the phase telescope you clearly and sharply see the condenser iris aperture (NOT the field aperture), try to open and close it and it shows in focus.
All I've seen is a yellow light circle from the lights, I think my DIY phase telescope might not be an actual phase telescope, just a tube with lens... I'll try again tomorrow, I should go to bed... Thanks

MicroBob
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Re: DIY phase telescope / microscope collimation

#4 Post by MicroBob » Sun Jan 23, 2022 8:09 am

Hi imkap,
to help you with your design I tested my Zeiss Jena phase telescope. It works with Zeiss West and other systems too. When the draw tube is fully pused it in focusses a little beyond infinity. When pulles out to the maximum it focusses to about 125mm, measured from the flange with which it sits on the end of the tube of the microscope. The objective starts at 160mm so this setup is what one would expect.

Bob
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Hobbyst46
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Re: DIY phase telescope / microscope collimation

#5 Post by Hobbyst46 » Sun Jan 23, 2022 8:53 am

Zeiss, Nikon, B&L phase telescopes all perform fine on the Zeiss microscope.

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patta
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Re: DIY phase telescope / microscope collimation

#6 Post by patta » Sun Jan 23, 2022 12:43 pm

Well, a phase telescope isn't much more than a tube with lens. (though the same can be said of any optics :lol: )

To see if it is working right, a way is to take it out from the microscope, look in it, it should focus at about 170 - 200mm distance, like a small macro telescope
that is its job!
When mounted instead of an eyepiece, it should focus in the middle of the objective

if it is way off those 200mm, try adjust the tube or lens distances.

As written before, you should be able to focus clearly the iris of the condenser.

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imkap
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Re: DIY phase telescope / microscope collimation

#7 Post by imkap » Sun Jan 23, 2022 3:21 pm

Hi, thanks for the suggestions. I had some success with combining different tube lengths with different mag eyepieces for focusing various parts of the optical path... It didn't work as I expected, I thought it will be different... I'll go make a collimation concentric circle filter thing now, I realized that the plastic toothpick container is the same size as a microscope filter, so I'll make one out of this... :idea:

I'm using this article as some reference, we'll see what happens...

http://www.microscopy-uk.org.uk/mag/ind ... ation.html

I found that KPL 8x eyepieces are useless for this application, but C8 and c12.5 work fine

Hobbyst46
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Re: DIY phase telescope / microscope collimation

#8 Post by Hobbyst46 » Sun Jan 23, 2022 3:59 pm

PM sent

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imkap
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Re: prism alignment / DIY phase telescope / microscope collimation

#9 Post by imkap » Wed Jan 26, 2022 11:59 pm

I think I have succeeded, I have been able to focus on the field diaphragm and the filter carrier with a DIY phase telescope made out of 2 different C eyepieces (12,5x and 8x). I'll write what I did here, so any comments are welcome I'm just trying to learn and using logic :mrgreen:

I have printed a few similar concentric circle "filters" on a transparent foil. First put one on the bottom glass over the field diaphragm and the other one on the filter holder as it is fixed and cannot be calibrated. When using darkfield filters it makes much difference if it is centred, not so important for colour filters.

With a Phase Telescope in the eyepiece hole and no objective:
1. I've aligned the arm and the head to be in 'perfect' line with the field diaphragm and the filter holder.
2. I put the field lens on and calibrated their centring screws so that the 2 concentric circle filters are still aligned with each other.
3. Put the condenser on and centred it without the flip-top lens observing the circles again.
Now I put the objective and the eyepiece with 2 squares visible inside
4. Aligned the flip-top so the centre is the same as without it.
5. Centred the condenser iris while the flip top is on...

It seems good now and darkfield doesn't have weird reflections all around anymore. I'll go and look into my friends lab soon so I'll compare how things look like on a professionally aligned scope, hopefully I'll learn something.

At the end of course I've spotted a problem with the head, as the binocular tubes had a tilt (5-10 deg) which I didn't spot before :roll: . I managed to open the head and fiddle with the prisms and now it is better, still not ideal, but quite usable... I kind of got used to the way it was, but nobody else did.
It is a bit of a frustrating job to do as you have to assemble the head back every time to check what you did :D and not sure of the outcome...

Good thing is that I did successfully clean all of the prisms and the glass is flawless on most, but there was quite a bit of fungus on the exit of the left one so now that I've wiped them off there are fungus marks on the coating. Right one is luckily 100% clean so can be used for photography. Also the coatings are falling off due to fungus on some and old age on other. I'll try to recoat with something black.
Any advice is welcome, I couldn't find much info about an of this anywhere. Except one pdf where they just explain the eyepiece tube collimation and mention the prism tilt as a bigger problem.

Hobbyst46
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Re: prism alignment / DIY phase telescope / microscope collimation

#10 Post by Hobbyst46 » Thu Jan 27, 2022 12:19 pm

imkap wrote:
Wed Jan 26, 2022 11:59 pm
When using darkfield filters it makes much difference if it is centred, not so important for colour filters.
Never got a satisfactory result with darkfield "filters" in any part of the turret condenser. Luckily the turret condenser includes a dedicated DF position.
...1. I've aligned the arm and the head to be in 'perfect' line with the field diaphragm and the filter holder.
Wow again ! bravo !
given the rigid attachment of the arm to the base and the head carrier to the arm, with precision bolts and location pins, that is challenging in my opinion !!
At the end of course I've spotted a problem with the head, as the binocular tubes had a tilt (5-10 deg) which I didn't spot before
between which lines/plates is the tilt angle ?
I'll try to recoat with something black.
I find that sticky matt black sheets from 3M do a better job than black paint.
I hope you be will be able to get a trinocular head some day, then the binocular head is returned to the shelf or drawer and we never look back...

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imkap
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Re: prism alignment / DIY phase telescope / microscope collimation

#11 Post by imkap » Thu Jan 27, 2022 3:08 pm

Hobbyst46 wrote:
Thu Jan 27, 2022 12:19 pm
Never got a satisfactory result with darkfield "filters" in any part of the turret condenser. Luckily the turret condenser includes a dedicated DF position.
What kind of turret do you have? I have the usual old Zeiss condenser with 0.9 flip top
Hobbyst46 wrote:
Thu Jan 27, 2022 12:19 pm
given the rigid attachment of the arm to the base and the head carrier to the arm, with precision bolts and location pins, that is challenging in my opinion !!
I've mostly done this with aligning the whole arm/focusing mechanism (basically the whole scope) to the round base. When removed, it needs to be centred again together with the condenser holder, which can also go a bit left or right... It's a bit lengthy but possible. I'll write some detailed info on what I did after some time when I'm sure I did it right :mrgreen:
Hobbyst46 wrote:
Thu Jan 27, 2022 12:19 pm
between which lines/plates is the tilt angle ?
Tilt is between the images when viewing:
It was something like this (this is an illustration, I didn't photo before):
Image
And now it is like this:

Image

In the meantime I found a head collimation guide for an Olympus Jentzsch head and it mentioned 2 eyepieces with a reticule. So I made this out of 2 hopelessly delaminated Zeiss oculars and a reticule printed on foil, I think these are fairly centered, but not sure 100% I need to buy a very thin marker and turn them on some machine to find the centre and now I'm infected with the infamous virus so can't go to shops or anywhere...
Image
Hobbyst46 wrote:
Thu Jan 27, 2022 12:19 pm
I find that sticky matt black sheets from 3M do a better job than black paint.
I hope you be will be able to get a trinocular head some day, then the binocular head is returned to the shelf or drawer and we never look back...
I'll try with black sheets as they seem far less messy than black paint :D
I'll get a trinocular head hopefully, but the ones on eBay lately are on the expensive side and it would be great if it was factory aligned so don't need to tamper inside. Although maybe I can master the subject until then and buy a cheap for parts not working head... :mrgreen: Not sure if I'll find one very soon.
The second thing I found would be something like this, but this includes more prisms which might or might not be aligned well...
I'll see what comes up first at a reasonable price

Image

Currently when taking pictures I have some glow in the middle of the image. It can be visible while looking through but only when looking at certain angle. I just have to note it has been there before I fiddled with the head 8-) Hopefully it is the prism paint missing that is causing the problems, although I'm not 100% sure. We'll seen when I tape them . Here it is

Image
Image

Hobbyst46
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Re: prism alignment / DIY phase telescope / microscope collimation

#12 Post by Hobbyst46 » Sat Jan 29, 2022 5:27 pm

imkap wrote:
Thu Jan 27, 2022 3:08 pm
Hobbyst46 wrote:
Thu Jan 27, 2022 12:19 pm
Never got a satisfactory result with darkfield "filters" in any part of the turret condenser. Luckily the turret condenser includes a dedicated DF position.
What kind of turret do you have? I have the usual old Zeiss condenser with 0.9 flip top
I have tried it with the basic condenser (1.3 flip top lens) and the turret condenser - Cat #465277, achromat-aplanat 1.4 phase contrast condenser. All failed.
The latter condenser has a dedicated "D" (darkfield) port; it works with low and intermediate NAs, provided that the top lens is oiled to the slide bottom. It also yields DF (though not as good) if the contact liquid is water or glycerol, instead of oil. Glycerol is easily removed with water.

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imkap
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Re: prism alignment / DIY phase telescope / microscope collimation

#13 Post by imkap » Sat Jan 29, 2022 6:44 pm

Hobbyst46 wrote:
Thu Jan 27, 2022 12:19 pm
Never got a satisfactory result with darkfield "filters" in any part of the turret condenser. Luckily the turret condenser includes a dedicated DF position.
I have tried it with the basic condenser (1.3 flip top lens) and the turret condenser - Cat #465277, achromat-aplanat 1.4 phase contrast condenser. All failed.
I found your post on the forum when you bought the turret, didn't know it had darkfield too. Great idea with balloon blower ball :mrgreen: :mrgreen: I'll get this sometime.
How much benefit you have with 1.3 flip top over the 0.9? I'm thinking about buying it there is one not too expensive 30£ on ebay currently.
I had some success with the darkfield filters, printed different sizes of the stop (mostly use 19-21mm). With 20x and 25x objectives it works great, with 40x it's almost good...

Hobbyst46
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Re: prism alignment / DIY phase telescope / microscope collimation

#14 Post by Hobbyst46 » Sat Jan 29, 2022 8:23 pm

imkap wrote:
Sat Jan 29, 2022 6:44 pm
How much benefit you have with 1.3 flip top over the 0.9? I'm thinking about buying it there is one not too expensive 30£ on ebay currently.
I never had a 0.9 so cannot compare. Actually I rarely use it, since the turret condenser is much better. More flexible, especially the phase contrast which I use a lot. Not to mention the chromatic corrections.

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