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Just picked this up from Brunel Microscopes

Got it to centre binocular heads and the like for which it looks perfect.

Google translate is not helping much however, can anyone translate/explain text.

I imagine the numbers are to do with stage flatness? Thanks

Here is a similar animal from B&L, in English.
I am guessing that the centration is based on a vernier type slide holder that is part of the maintenance equipment, or perhaps is attached onto the base plate of the stereo, just my guess...

Thanks Hobbyst46,

Here is a similar animal from B&L, in English.
I am guessing that the centration is based on a vernier type slide holder that is part of the maintenance equipment, or perhaps is attached onto the base plate of the stereo, just my guess...

I suppose those numbers indicate how much off flat the slide is on x and y planes.

Glad I only need it to centre the binocular head!

I have just looked on Brunel's site, and they have a similar item from Jena
'Collectible' and priced accordingly.

The descriptive text states

We have included this Zeiss Jena item here because of its rarity value. Dating from about 1920 this is a numbered cross hair slide used for centring the rotating circular stages of polarising microscopes. Its presentation box is in truly excellent condition. A collector's item.

I am not familiar with these slides, but: If that's their intended purpose, perhaps the numbers are the calibrated offset from the true centre of the slide [?]

MichaelG.

75RR wrote:Thanks Hobbyst46,

Here is a similar animal from B&L, in English.
I am guessing that the centration is based on a vernier type slide holder that is part of the maintenance equipment, or perhaps is attached onto the base plate of the stereo, just my guess...

I suppose those numbers indicate how much off flat the slide is on x and y planes.

Glad I only need it to centre the binocular head!

From the German text I think that one is supposed to prepare for centration by locating the small cross (in the middle of the circle) at a certain location on the stage...

MichaelG. wrote:I have just looked on Brunel's site, and they have a similar item from Jena
'Collectible' and priced accordingly.

The descriptive text states

We have included this Zeiss Jena item here because of its rarity value. Dating from about 1920 this is a numbered cross hair slide used for centring the rotating circular stages of polarising microscopes. Its presentation box is in truly excellent condition. A collector's item.

I am not familiar with these slides, but: If that's their intended purpose, perhaps the numbers are the calibrated offset from the true centre of the slide [?]

MichaelG.

Had seen the other one they had - I suppose 'collectable' makes all the difference



- my non-collectable one was:

Carl Zeiss Cross Hair Slide

A cross hair slide used for centring circular rotating stages and ensuring flatness of the stage. Complete with original case and ion very good condition. Labelled in ink with batch number and QC authority.

Price £20.83 + vat

not sure where that 0.83 came from, currency conversion?

From the German text I think that one is supposed to prepare for centration by locating the small cross (in the middle of the circle) at a certain location on the stage...

That makes sense, but then how does the flatness work?

Centering needs an eyepiece cross and a stage cross for absolute accuracy.

https://archive.org/details/APracticalG ... ollimation

Great B&L etching by the way - way better than the Zeiss sticker!

As far as I know the stated values have to be set at the scales of the object guide on to of a rotating polarisation microscope stage. It is intended for the microscope table with the stated number and was sold together with it. By using it you can quickly center the stage when necessary. "Nonius" means vernier scale with 0,1mm resolution.
I have never heard of flatness testing with such a centering slide, but I don't know much about polarisation microscopy in general.

Bob

75RR wrote: - my non-collectable one was:

Carl Zeiss Cross Hair Slide

A cross hair slide used for centring circular rotating stages and ensuring flatness of the stage. Complete with original case and ion very good condition. Labelled in ink with batch number and QC authority.

Price £20.83 + vat

not sure where that 0.83 came from, currency conversion?

That's a much better price !!

MichaelG.

MicroBob wrote:... It is intended for the microscope table with the stated number and was sold together with it. By using it you can quickly center the stage when necessary. "Nonius" means vernier scale with 0,1mm resolution.

... and "Tisch", I have just learned, means Table.

Thanks, Bob.

MichaelG.

It is intended for the microscope table with the stated number and was sold together with it.

That is pretty amazing precision!

The object guide on the rotating stage of my 1911 "Großes Forschungsmikroskop" already has a vernier scale, as finely engraved as if it were a measuring tool.

MicroBob wrote:... as finely engraved as if it were a measuring tool.

Which is what it is, of course

MichaelG.

75RR ... I think you might find this interesting:
https://sci.techniques.microscopy.narki ... on-vernier

I've been pondering the usage of your slide, and admit that I was perplexed ... The modern Zeiss user manuals describe the centring method that I use intuitively on my CTS/Vickers: because they all have stage centring screws !

See for example para. 3.1.8.5 on p55 of:
https://www.hitechinstruments.com/Porta ... Manual.pdf

But, Aaron's first paragraph [in my first link] provides a very reasonable explanation.

MichaelG.

Nice to read how it was designed to be used.

Thought at first the numbers in the link were the same as that of my centering slide - it wasn't, but it was pretty close!

Yes, I also centre my stage with the centering screws and an eyepiece. Can be done quite quickly with a bit of practice.

I have and use one of those Pol centering objectives, a 25x/0.60 Neofluar with retracting tip - I have learned to be careful when I touch it as it is easy to inadvertently de-center it.

I will be using it to collimate my binocular head as per Ron Green's manual

I do not have a polarizing scope, neither an intention to get one.
So if the B&L slide at my possesion might be valuable to anyone, I can sell it at a very modest cost.

Hobbyst46 wrote:I do not have a polarizing scope, neither an intention to get one.
So if the B&L slide at my possesion might be valuable to anyone, I can sell it at a very modest cost.

Do not confuse the original and main purpose of the cross hairs slide with what else it can be used for.

Forget polarizing microscope, think collimating your binocular head.

May I suggest you read Ron Green's booklet before you get rid of that cross hairs slide.

https://archive.org/details/APracticalG ... ollimation

It is what I got it for.

MichaelG was simply tracing its (interesting) history. I am pretty sure it always had dual use, i.e. centering pol stages and collimating binocular heads.

Thanks 75RR for the good advice!