MicrobeHunter.com Microscopy Forum

I believe the condenser prisms has a pin that fits in a groove or hole, which ensures that they are positioned the right way, no? You're right. I should have just looked. That answers my questions. I had mentally painted myself into a corner there, but yes there is an alignment pin. For some reason...

One of the other orientations may be close, and that's usually when you flip it upside down, if I remember correctly. But flipping it so that it is inserted backwards becomes way off and results in a BFP with a large number of narrow interference stripes. But the condenser prism are in a ring. They...

Sorry, I'm not sure what you are saying here. This is the situation you are after: If you look at the green box above, note the outward pointing optical axis is on the left not the right as in the original. Technically I guess a rotation would make the green box have the optical axis point in, but ...

Is rotating the top prism on the vertical axis like this still a valid set up?

Come to think of it, the condenser discs can rotate freely, so the top prism, even though it's locked in a slider could rotate that way too.

So does the U-DICTS centered knob (unlike the U-DICT screw which moves the prism in and out) rotate the prism? And the side lever moves the assembly in and out?

I don't have a U-DICTS slide to check that.

I hadn't noticed it before, but isn't the patent diagram wrong? Shouldn't the optical axis of the Nomarski prisms mirror each other? The wedge with the axis pointing out of the drawing should be the top wedge for the objective prism and be the bottom wedge for the condenser prism. The figures show t...

In the one ebay side picture, it looks like a vertical track, so the slider lever must wedge the prism up to the top.

Any diagrams and measurements would be appreciated just to get an idea. I assume at some point I'll have to buy one.

I have U-DICT slides, but for the U-DICTS which has not only a rotating knob but also a "lateral adjustment" shift hence the S. So some objectives have back focal planes at -19.1mm and some are at -25.0mm. So the pull lever, I believe, in Normal (pulled out) has the prism raised 6.1mm. For BFP1, pus...

I'm not doing lens assemblies. I just need to test wedge prisms, so I'm putting together Python with matplotlib and some of the different math packages.

https://www.researchgate.net/post/Is_there_a_rule_of_thumb_to_determine_the_back_focal_plane_of_objective_lens I've used the method described by Paolo Pizza with good results. It's much harder at 40x and above. Thanks. I'll take a look. I hadn't thought about get a linear set of position points. I ...

I'm still trying to figure out a bunch of this as well.

Forgive me if I am missing the point, but; surely [ when in use as intended ] the back focal plane of an infinity-corrected objective is at infinity. It is only when either used incorrectly, or used in combination with the tube lens, that there is an identifiable plane. MichaelG. . . https://www.mi...

Does anyone have a table of the back focal plane positions of the following objectives? Also does anyone have pointers to the best procedure to measure the back focal plane position? Thanks. Olympus Objectives: 37543 UPLFL 20x 0,5 37553 UPLFL 20x PH 0,5 37557 UPLFL 20x PH/NH 0,5 UPLFLN20x 0,5 LUCPLF...

So c-axis and z-axis are the same when looking around for things about quartz. Z-cut means a flat optic with the z as the normal.

Working through finding Python code to ray trace through glass surfaces to get some DIC prism designs hammered out.

This code is tracing through an aspherical lens:

It looks like the I can count on a consistent atomic crystal structure. I was worried it grew with at least four merging. The left blue and left red are letting some light through, but it is cross-polarized and the same light level shows without the prism, basically very dark – and black if the LED ...

Quartz's doubling is much more subtle, nothing like calcite's. A thick line like that, especially with subtle texturing, will obscure the doubling effect pretty well. You need sharp details with sharp edges, and better yet would be viewing it through a microscope. Believe me, the doubling will defi...

hans wrote: ↑

Sat Feb 20, 2021 6:16 am

I bought a few things from that seller (the WF10X/22 eyepieces Scarodactyl reviewed, calibration slide, some reticles) and the quality seemed fine.

I have that light source now. I'm just trying to figure out the best way to test it.

Do you have a pair of linear polarizing filters? Assuming there is a chance of a good continuous structured crystal, put the crystal in between to cross-polarized filters that are extinguishing the light. If there is birefringence, there should light showing again as if a quarter waveplate were ins...

Scarodactyl wrote: ↑

Sat Feb 20, 2021 5:24 am

Do you have a pair of linear polarizing filters?

I have to hunt them down. Microscope stuff is in boxes right now.


But you see the seed in the center. So I don't think I can cut out a flat blank of any useful size.

That is a single synthetic crystal pictured in the last image. How are you detecting birefringence? The short piece is cut out of one of those large ones. The seed is in the center, so at best I have four long crystals grow off the seed's four sides. Yet I'm wondering if the structure is even messi...

So I cut and polished a section from a synthetic quartz rod. Problems: 1) I don't see any blatantly visible birefringence. After basically making a box shape out of it with polished sides, you'd think there would be some visible doubling. (I'll get polarizers back out, my microscope set-ups are in b...

wstenberg wrote: ↑

Thu Feb 18, 2021 12:49 am

100% Carl Zeiss.
Any else have one like this?

Toolmakers microscope?

Also remember that there are no perfect crystals in nature so you may have to play with it a bit. I usually do. Greg I'm going to polish opposite surfaces at a right angle to this. This is a piece I cut off a synthetic quartz, 8 inch long and 1 inch diameter. It's just that I had assumed that the a...

If I'm looking perpendicular to the optical axis, I thought I would see more birefringence -- actually any.

Supposedly this is optical quartz. It has a hexagonal cross section, so that should define the optical axis as being perpendicular to the hex.

Am I missing something here?

Would like to find an enthusiast for this: I have a Vanox stand. If you’ll cover packaging and shipping, I’ll send it to you. Otherwise, I guess I’ll break it down for parts. The masking tape is to protect it from dust. It should come off easy, and any residue can be cleaned off with alcohol. This i...

For this video, I'm finding the comment section useful: https://www.youtube.com/watch?v=RtV_uPmhCNg

So I separated it from the base. There are a bunch of beam splitters, and Phase Contrast disk, and a laser autofocus assembly inside. If some one wants this, let me know. It's way lighter without the huge cast iron frame, and one could learn a lot -- and maybe Arduino it. Unless you need for a real ...

[ what size is your LED array ? ] I want a 100mm by 300mm aluminum mount of an array of star LEDs. Each gets a condenser lens aimed at the light mixing rod, or a fiber that is then aimed at the light mixing rod. Basically the captured light is run through a mixer of some sort and all done in a way ...

b. It is possible and fairly easy to couple a LED to a 1mm diameter quartz fiber without a lens. Moreover, removal of the integral epoxy lens of the LED such that the fiber end nearly touches the die enhances the amount of light that reaches the fiber. I'm trying to apply this to 24 LEDs. I'd like ...