Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

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MichaelG.
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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#61 Post by MichaelG. » Wed Aug 05, 2020 4:40 pm

Sorry Hans, I’m struggling with the ray trace

Taking the thinner element ... can you tell if it is plano-concave or plano-convex ?

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#62 Post by hans » Wed Aug 05, 2020 9:49 pm

Inspired to look at patents by the discussion in the 181 eyepiece thread, US patent 4,715,697 appears to describe the 410/420 "telescope system" (how they refer to everything starting at the telan lens) in excruciating detail. Looks like there is also some interesting background on the progression of the infinity systems with references to other patents, which I have not tried to follow.

The description of fig. 1 showing the binocular path simply describes this element (labeled VI) as a doublet with both external surfaces having infinite radius. Then shortly after: "The combination of optical elements I-VI' and I-VI" corrects for the 0.6 percent lateral color deliberately introduced by the objective 12."

The description of fig. 2 showing a trinocular camera port is more explicit: "The color correcting doublet X has a surface R8 with an infinite radius of curvature, an inner surface between the two elements of the doublet which are X1 and X2 which internal surface has a radius of curvature of R9. Further the surface of the doublet facing the focal plane of the camera 22 is designated by R10 and is preferably flat."

I suspect "color correcting doublet X" is located in the Photostar shutter assembly, but I don't have one... apochronaut?

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#63 Post by MichaelG. » Wed Aug 05, 2020 10:51 pm

hans wrote:
Wed Aug 05, 2020 9:49 pm
Inspired to look at patents by the discussion in the 181 eyepiece thread, US patent 4,715,697 appears to describe the 410/420 "telescope system" (how they refer to everything starting at the telan lens) in excruciating detail. […]
.

Brilliant find, Hans
‘Comprehension Test’ scheduled for tomorrow ... it’s bedtime now !

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#64 Post by hans » Thu Aug 06, 2020 3:40 am

The patent is pretty much just a list of optical elements but there are a few other interesting hints toward design intent besides the ones I already quoted. The terminology used in the patent is:
  • tube/telan lens --> telescope objective
  • glass cylinder --> glass plug
  • thing discussed in this thread --> color correcting doublet
"The prior art infinity corrected systems, such as the type described above, place substantial limitations on the positioning of the microscope body due to residual axial color and field aberrations. These residual aberrations were exaggerated by changes in the spacing between the microscope objective and telescope objectives exceeding 25 mm."

"The lengthening and shortening of optical paths by the addition of glass plugs or their removal is well known in the art."

"By use of the present invention, a microscope body having typically a lateral color correction of 0.6 percent can be coupled with a microscope objective having a deliberately designed-in lateral color aberration of 0.6 percent such that the resultant combination of the microscope body with the microscope objective can substantially cancel out a major portion of this deliberately-introduced lateral color in the microscope objective. In addition, the present invention does not introduce an appreciable amount of axial color aberration. With the invention, as disclosed, a minimal number of optical elements can be used at a lowering in overall cost of the microscope system such that a high-performance microscope body is available at a substantially lower cost than the prior art."

Sort of sounds like at least part of the motivation for splitting corrections between the telescope objective and color correcting doublet is to modify what aberrations are present in, and get more idealized behavior of, the infinity space.

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#65 Post by hans » Thu Aug 06, 2020 4:15 am

apochronaut wrote:
Wed Aug 05, 2020 11:02 am
Very good. Wonder what glass formulas they used?
I have no idea how closely manufacturing typically ends up following patents for optical stuff like this. In the patent the color correcting doublets for the left eye, right eye, and camera port are all slightly different. The left and right eye differ only in thickness, perhaps to make up for a path length difference through the splitter? The one for the camera port has a different curvature which raises some question about the afocal setup I tested using the complete eye tube above the camera port. The same two glasses are shown in all cases, with closely matched indices of refraction but differing Abbe numbers, which I think indicates the design is not similar to a typical achromatic doublet?

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#66 Post by MichaelG. » Thu Aug 06, 2020 6:02 am

Refractive Index specified to five decimal places is a bit scary :o

MichaelG.

.
International Glass Code effectively rounds it to three
https://en.wikipedia.org/wiki/Glass_code

.
From Schott ‘Pocket Catalog’
From Schott ‘Pocket Catalog’
DE06AF48-F16D-4A26-93CF-81B2FDD37959.jpeg (135.78 KiB) Viewed 3455 times
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Source: https://wp.optics.arizona.edu/optomech/ ... e_2003.pdf
Note: Final page has the Abbe Diagram for Schott optical glasses.
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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#67 Post by MichaelG. » Thu Aug 06, 2020 5:29 pm

For info.

I created two ‘Custom Glasses’ in RayLab, as per the patent, and here’s where they lie on the Abbe Diagram:
.
C9415BEE-E0DD-4726-99C1-0E5B01F642F7.jpeg
C9415BEE-E0DD-4726-99C1-0E5B01F642F7.jpeg (110.38 KiB) Viewed 3438 times
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I then ‘built’ item X, as per the patent
.
571F3389-40AC-4F11-BF1C-8DBA4EB5DC1B.jpeg
571F3389-40AC-4F11-BF1C-8DBA4EB5DC1B.jpeg (56.15 KiB) Viewed 3438 times
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E9035C03-F7C8-4A45-9773-D54A86AD3452.jpeg
E9035C03-F7C8-4A45-9773-D54A86AD3452.jpeg (85.34 KiB) Viewed 3438 times
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... and used wavelengths of 480nm and 643.8nm [which are typical modern reference values]

Predictably enough, the doublet is very nearly a flat window
RayLab makes it slightly negative, at 1.13e+04 metres effective focal length
... but I have no idea how accurate that might be !!

It’s not worth trying to show a ray diagram ... but the next bit is good
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381BD1E2-6E02-42EC-B731-2C5BD4E57CEB.jpeg
381BD1E2-6E02-42EC-B731-2C5BD4E57CEB.jpeg (99.13 KiB) Viewed 3438 times
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Note: X-axis is effective focal length, and Y-axis is wavelength
... which, to me seems the wrong way round to present it [but who am I to complain?]

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#68 Post by hans » Thu Aug 06, 2020 7:38 pm

Thanks Michael, if I follow, that plot of axial/longitudinal CA is confirming that the doublet does not behave like a typical achromat, which would show primarily quadratic and higher-order residuals? Can the software also show transverse/lateral CA? Would be interesting to compare with "0.6 percent lateral color" as mentioned in the patent although I am not sure what exactly the interpretation of that percentage is, presumably a difference in magnification between two reference wavelengths?
MichaelG. wrote:
Thu Aug 06, 2020 5:29 pm
Note: X-axis is effective focal length, and Y-axis is wavelength
... which, to me seems the wrong way round to present it [but who am I to complain?]
I find that convention a bit strange also but it seems to be common, for example the plots on the Wikipedia pages for achromat and apochromat are oriented the same way.

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#69 Post by Zuul » Thu Aug 06, 2020 8:05 pm

Where are you headed with this further investigation? Are you just satisfying curiosity at this point?

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#70 Post by MichaelG. » Thu Aug 06, 2020 8:35 pm

Zuul wrote:
Thu Aug 06, 2020 8:05 pm
Are you just satisfying curiosity at this point?
In a word ... Yes

I need to get some practice with the App, and this is an interesting exercise.

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#71 Post by Zuul » Thu Aug 06, 2020 8:46 pm

MichaelG. wrote:
Thu Aug 06, 2020 8:35 pm
Zuul wrote:
Thu Aug 06, 2020 8:05 pm
Are you just satisfying curiosity at this point?
In a word ... Yes
That's cool. I was just making sure there wasn't some super secret optical skunkworks ready to start grinding custom glass. :D

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#72 Post by MichaelG. » Thu Aug 06, 2020 9:03 pm

hans wrote:
Thu Aug 06, 2020 7:38 pm
... Can the software also show transverse/lateral CA? Would be interesting to compare with "0.6 percent lateral color" as mentioned in the patent although I am not sure what exactly the interpretation of that percentage is, presumably a difference in magnification between two reference wavelengths?
.

I would agree ... but I’m still trying to understand some of the terminology and presentation.

The truth is ... many years ago, when I worked at Kodak; a clever chap, locked away in his little office, still did optical design ‘manually’ ... and I was totally awestruck.

Then computers came along, and artistry gave way to brute force computation. [try five million variations and see which one gives the best answer]

Now I have an App on the iPad which lets me explore things !!

I think [but could be mistaken] that the change of effective focal length with wavelength [in the plot above] can be interpreted as change of magnification ... and therefore a representation of Lateral CA

Sorry but I can’t really get my head around what object and image I should use in a ray diagram of what is effectively a window. ... Any suggestions ?

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#73 Post by hans » Thu Aug 06, 2020 11:13 pm

Zuul wrote:
Thu Aug 06, 2020 8:05 pm
Where are you headed with this further investigation? Are you just satisfying curiosity at this point?
The practical questions I still have are related to the difference in internal radius between color correcting doublets VI in the binocular path and X in the camera path shown in the patent. Are they actually different in manufactured Photostar systems? If so, does the difference in radius have more to do with the preceding, or following optics? One could hope that the difference in radius is mainly related to some difference between the 181 eyepiece and the Photostar relay optics, such that substituting (VI + 181) in place of (X + Photostar relay) would not significantly degrade image quality. Obviously, not knowing how closely manufacturing actually followed the design in the patent, there will be no definitive answer without experimentation, but the ray tracing is interesting and I think could give some useful insight.
MichaelG. wrote:
Thu Aug 06, 2020 9:03 pm
I think [but could be mistaken] that the change of effective focal length with wavelength [in the plot above] can be interpreted as change of magnification ... and therefore a representation of Lateral CA
Well, my optical education so far consists mostly of reading Wikipedia and sawing/blow-torching parts of old 410s (usually in the wrong order) but I am almost certain they are effectively independent in complex optical systems. On the other hand, in sufficiently simple systems, or with enough simplifying assumptions (thin lens, paraxial, whatever...) it does seem likely they would end up closely related. Not sure where on that spectrum this doublet falls.
MichaelG. wrote:
Thu Aug 06, 2020 9:03 pm
Sorry but I can’t really get my head around what object and image I should use in a ray diagram of what is effectively a window. ... Any suggestions ?
As a simple, concrete starting point is it possible to set up 1:1 magnification with some sort of idealized aberration-free element in the middle, 200 mm element-to-image, 10 mm diameter? (The exit pupil of my 10X objective appears to be roughly 10 mm.) I think that would give you an aberration-free real image roughly comparable to the intermediate image and the color correcting doublet could then be inserted at the appropriate position to see its effect. I imagine ray tracing software would provide a simple way to set up such a "stimulus" in a more abstract way without explicitly constructing an object plane and idealized lens, but if this one is more oriented to casual/educational use, maybe not.

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#74 Post by MichaelG. » Fri Aug 07, 2020 4:14 am

hans wrote:
Thu Aug 06, 2020 11:13 pm
MichaelG. wrote:
Thu Aug 06, 2020 9:03 pm
... Any suggestions ?
As a simple, concrete starting point is it possible to set up 1:1 magnification with some sort of idealized aberration-free element in the middle, 200 mm element-to-image, 10 mm diameter? (The exit pupil of my 10X objective appears to be roughly 10 mm.) I think that would give you an aberration-free real image roughly comparable to the intermediate image and the color correcting doublet could then be inserted at the appropriate position to see its effect. I imagine ray tracing software would provide a simple way to set up such a "stimulus" in a more abstract way without explicitly constructing an object plane and idealized lens, but if this one is more oriented to casual/educational use, maybe not.
It may be possible ... but, if so, it is beyond my current skill-set

Here is the 2018 ‘manual’ for RayLab, which you might find it interesting to explore:
http://www.raymak.com/wp/raylab-manual-2018/

MichaelG.

.

P.S. __ Although I have enormous admiration for RayLab’s author ... I am reminded of this:
I told him I had been that morning at a meeting of the people called Quakers, where I had heard a woman preach. Johnson: "Sir, a woman's preaching is like a dog's walking on his hind legs. It is not done well; but you are surprised to find it done at all."
Boswell: Life
Ref. http://www.samueljohnson.com/expectat.html#53
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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#75 Post by hans » Fri Aug 07, 2020 6:31 am

MichaelG. wrote:
Fri Aug 07, 2020 4:14 am
Here is the 2018 ‘manual’ for RayLab, which you might find it interesting to explore:
Looking through the list of elements, something like this might work:
  1. object plane
  2. 200 mm spacing
  3. aperture, 10 mm diameter, approximating objective exit pupil
  4. ray transfer matrix set to thin lens form, f = 100 mm, with both reference planes coincident with the aperture
  5. 200 mm spacing
  6. image plane
I think lateral CA at the edge of the FOV could then be observed in the spot diagram analysis mode looking at rays originating from a point 10 mm off the axis in the object plane. If that setup works and shows the expect result (perfect focus in the same location for all wavelengths traced) then variation of the spot center vs. wavelength when the doublet added is what "percent lateral color" in the patent would be referring to, I think.

Of course, as far as I saw, the patent only says 0.6% total between the telescope objective and doublet, so the next stop on the slippery slope to modelling the entire microscope would be adding the parameters given for the telescope objective and modifying the object plane, aperture, and ray transfer matrix to project an aberration-free image from infinity...

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#76 Post by MichaelG. » Fri Aug 07, 2020 7:21 am

hans wrote:
Fri Aug 07, 2020 6:31 am
.
Looking through the list of elements, something like this might work:
  1. object plane
  2. 200 mm spacing
  3. aperture, 10 mm diameter, approximating objective exit pupil
  4. ray transfer matrix set to thin lens form, f = 100 mm, with both reference planes coincident with the aperture
  5. 200 mm spacing
  6. image plane
.

It looks like you must be way ahead of me already, Hans

I have found no way of ‘setting’ the ray transfer matrix
... I can only see it as a ‘report’ on what has been input graphically.

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#77 Post by hans » Fri Aug 07, 2020 7:48 am

MichaelG. wrote:
Fri Aug 07, 2020 7:21 am
I have found no way of ‘setting’ the ray transfer matrix
... I can only see it as a ‘report’ on what has been input graphically.
It looks like there is an element you place graphically, described in section 2.2.11. of the manual, that allows you to enter arbitrary coefficients but also has a simplified thin lens mode where you enter the focal length and it fills in the coefficients for you.

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#78 Post by MichaelG. » Fri Aug 07, 2020 10:23 am

Well-Spotted, Hans
I will investigate

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#79 Post by MichaelG. » Fri Aug 07, 2020 8:04 pm

.

After struggling for a while ... I gave-up, and wrote to Kamyar Ghandi [RayLab developer] for guidance.
To model a thin lens you probably want the two surfaces to be coincident. But having them perfectly coincident is likely to cause issues. So leave a small sub-millimeters gap between the two surfaces.
.
Applying this advice was a great help
I then found that the same applies to the ‘aperture’
... so I modelled 199.9mm to the stop, 200.0mm to the first surface of the lens, and 200.1mm to the second surface.

All works fine; except that in ‘thin lens mode’ we get ZERO chromatic aberration. :(

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#80 Post by hans » Fri Aug 07, 2020 8:17 pm

MichaelG. wrote:
Fri Aug 07, 2020 8:04 pm
All works fine; except that in ‘thin lens mode’ we get ZERO chromatic aberration.
This is good, I think, assuming you mean without doublet X? What I had in mind was that the thin lens and aperture could providing a simulated intermediate image with realistic reference length and focal ratio, while not introducing any confounding aberrations of their own, and giving the software a concrete object plane to work with. If you now add the doublet X 30 mm in front of the image plane, I think that should give a fairly realistic idea of what effect it would have on the intermediate image in the actual system.

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#81 Post by MichaelG. » Fri Aug 07, 2020 8:43 pm

hans wrote:
Fri Aug 07, 2020 8:17 pm
MichaelG. wrote:
Fri Aug 07, 2020 8:04 pm
All works fine; except that in ‘thin lens mode’ we get ZERO chromatic aberration.
This is good, I think, assuming you mean without doublet X? What I had in mind was that the thin lens and aperture could providing a simulated intermediate image with realistic reference length and focal ratio, while not introducing any confounding aberrations of their own, and giving the software a concrete object plane to work with. If you now add the doublet X 30 mm in front of the image plane, I think that should give a fairly realistic idea of what effect it would have on the intermediate image in the actual system.
Yes, without doublet X ...
I will have a play tomorrow, although I can’t see why the result would differ greatly from that with a simple source as the object.


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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#82 Post by hans » Fri Aug 07, 2020 9:58 pm

MichaelG. wrote:
Fri Aug 07, 2020 8:43 pm
...why the result would differ greatly from that with a simple source as the object.
I was thinking, to visualize lateral vs. longitudinal CA separately using the spot diagram analysis mode, it would be necessary to incorporate the doublet as part of a realistic image-forming system with defined object and image planes. With only a point source and doublet, is the spot diagram analysis even available?

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#83 Post by MichaelG. » Fri Aug 07, 2020 10:25 pm

hans wrote:
Fri Aug 07, 2020 9:58 pm
With only a point source and doublet, is the spot diagram analysis even available?
.
I can check tomorrow ... but I was using an extended source anyway
[ see the ‘pencil’ in post #13, which is showing as source and a virtual image thereof ]

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#84 Post by hans » Sat Aug 08, 2020 9:35 pm

Just tried crudely calculating "percent lateral color" from a test image. The first one I looked at is direct-telan.NEF from the ZIP file I linked earlier in the thread which is direct projection to the D5100 sensor with the head disassembled so that only the telan lens ("telescope objective") is in the path. r0 and b0 are pixel coordinates of an intersection point on the calibration slide in the lower left of the image, in the red and blue channels respectively. r1 and b1 are an intersection in the upper right.

Code: Select all

Python 3.8.1 (default, Jan 22 2020, 06:38:00) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.12.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import numpy as np                                                                                                                                  
In [2]: r0=np.array([835.,2709.])                                                                                                                           
In [3]: b0=np.array([826.,2715.])                                                                                                                           
In [4]: r1=np.array([4093.,632.])                                                                                                                           
In [5]: b1=np.array([4105.,625.])                                                                                                                           
In [6]: r=np.linalg.norm(r1-r0)                                                                                                                             
In [7]: b=np.linalg.norm(b1-b0)                                                                                                                             
In [8]: 2*(r-b)/(r+b)                                                                                                                                       
Out[8]: -0.006371378386379988
Surprisingly close to the 0.6% lateral color mentioned in the patent despite not knowing what the reference wavelengths are vs. the sensor red/blue channel responses, among many other potential inaccuracies. Could be taken as evidence that the telan lens is minimally corrective in terms of lateral color, leaving it almost entirely up to the color correcting doublet?

(This of course would be more easily done with software to make the measurements graphically, but I did not feel like researching and installing something appropriate. Any suggestions for ones that run on Linux? I have heard ImageJ?)

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#85 Post by MichaelG. » Sun Aug 09, 2020 5:01 am

hans wrote:
Sat Aug 08, 2020 9:35 pm
Just tried crudely calculating "percent lateral color" from a test image.

[…]

Surprisingly close to the 0.6% lateral color mentioned in the patent despite not knowing what the reference wavelengths are vs. the sensor red/blue channel responses, among many other potential inaccuracies. Could be taken as evidence that the telan lens is minimally corrective in terms of lateral color, leaving it almost entirely up to the color correcting doublet?

(This of course would be more easily done with software to make the measurements graphically, but I did not feel like researching and installing something appropriate. Any suggestions for ones that run on Linux? I have heard ImageJ?)
That’s encouraging, Hans

You may like to try the recursively named FIJI
https://fiji.sc/

I have barely dabbled, so cannot offer any useful guidance.

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#86 Post by hans » Wed Aug 12, 2020 2:07 am

A few notes from reading the patent more carefully and comparing with my heads:
  • The "telescope objective" does look like an air-spaced doublet as shown in the patent. (Checked with the violet laser.)
  • The difference in thickness shown in the patent for color correcting doublets VI' and VI'' (right and left binocular paths, respectively) is present in the heads.
  • Figures 3, 4, 5 are three different views of the 0/100 switchable trinocular head showing the camera path only -- 3 is side view and 4/5 are frontal views with the prism (labeled III) moved out of/into the path. There is no geometric path length given for the consolidated glass plug IX shown in those figures.
  • Plug IX in my head measures 58.4 mm. The patent shows 40.72 and 24 mm geometric path length for the prism and splitter (these are difficult to measure) but plug IX also begins ~16 mm further along the path in order to clear the sliding prism and there is ~10 mm gap between the prism and splitter.
I still don't understand the difference between the left and right color correcting doublets. The table in patent shows the same length through both paths of the splitter and as far as I can tell that is very close to true in the heads I have. Also, the dual-adjustable head that came with the teaching attachment has the difference, indicating it really is a left/right difference not just something related to diopter-adjustable vs. fixed eye tube. The eye tubes are angled inward slightly (several degrees total) but as far as I can tell from both the patent and my heads this happens in the mirrors after the splitter. Any ideas?
reichert-410-corrector-lr.jpg
reichert-410-corrector-lr.jpg (112.05 KiB) Viewed 3257 times

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#87 Post by MichaelG. » Wed Aug 12, 2020 7:28 am

I am completely out of my depth, Hans ... so I am following your exploits with interest, but am unlikely to be of any assistance. :oops:

My attempt at modelling doublet X was about my limit ... and [using RayLab] even the results from that are not easily interpreted without a lot more ‘context’

My model produced a very slightly negative power [which may be the result of rounding errors] but we know from the patent that the final image should sit 193.725mm above its final surface ... so without detailed knowledge of everything which precedes it, I am in the [beautifully colour-corrected] dark !!

The same would go for the eyepiece correctors, but with further complications.

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Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#88 Post by Zuul » Wed Aug 12, 2020 3:04 pm

Engineer 1: “the best correction is obtained by my optical formula!”

Engineer 2: “but my formula does the job 99.9% as well with half as much glass.”

Engineer 1: “it’s a multi thousand dollar instrument. Who cares about an extra 20 cents worth of glass?”

Engineer 2: “it’s not just the cost. The smaller element fits better and creates less light loss.”

Manager: “I can’t tell a difference and we need to start production. If you two can’t compromise, put one in the right tube, and the other in the left tube. Nobody is ever going to take these things apart and question it.”

MichaelG.
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Location: NorthWest England

Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#89 Post by MichaelG. » Wed Aug 12, 2020 3:42 pm

:lol:
Too many 'projects'

MichaelG.
Posts: 2458
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: Reichert 410 "Microstar IV" head -- corrective element present in binocular path but not trinocular camera port

#90 Post by MichaelG. » Wed Aug 12, 2020 9:32 pm

hans wrote:
Wed Aug 12, 2020 2:07 am
A few notes from reading the patent more carefully and comparing with my heads:
[…]
I still don't understand the difference between the left and right color correcting doublets. The table in patent shows the same length through both paths of the splitter and as far as I can tell that is very close to true in the heads I have. Also, the dual-adjustable head that came with the teaching attachment has the difference, indicating it really is a left/right difference not just something related to diopter-adjustable vs. fixed eye tube. The eye tubes are angled inward slightly (several degrees total) but as far as I can tell from both the patent and my heads this happens in the mirrors after the splitter. Any ideas?
I find this patent quite difficult to follow [even for a patent], because it describes more than one ‘implementation’ ... without clear boundaries. The text sometimes seems like a ‘stream of consciousness’.

I think, however, that the answer lies with the Prism IV and Mirrors V [see Figure.1 and the values in Table.I]

MichaelG.
Too many 'projects'

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