Poor man's polarized light microscopy

[75RR]

I think that at least some of the CA in results - not the POL maybe, but others - might have been caused by the photo eyepiece, although other factors might have contributed as well.

Sorting out image problems is frequently done in a series of steps, a good first step would be to match your photos to what you see through the eyepieces. CA can be dealt with later.

Incidentally, I have just finished a major overall of the photo setup, as follows:

1. Took apart all items installed on the head
2. Replaced the free-floating, curving piece of polarizer sheet with a more sturdy polarizer - the same piece but fitted inside a thin aluminum ring which, in turn, is forcefully fixed into the dovetail of the head - so the polarizer is flat and perpendicular to the optical axis
3. Set the camera to focus at infinity, using the autofocus feature and pointing at a remote road sign
4. Taped the focusing ring on the camera, to fix it in place, like I had done to the zoom ring
5. Seated the 8X KPL photo eyepiece into the head tube and verified parfocality between the photo eyepiece and viewing eyepieces
6. Improved the contact between the PVC spacer sleeve and the 1.25"->49mm telescope adapter, by using steel shims (~0.1mm thick) instead of the cellotape I had used before
7. Verified the height of the eyepoint above the photo eyepiece, by locating the smallest image
8. Attached the camera back to the adapter --- and was rewarded with exact parfocality between the camera and viewing eyepieces, better than I had before. This I check with a stage micrometer.
I added thick rubber foam stand-offs beneath the scope, to better eliminate desk-induced vibrations.
Will proceed to real-life tests...

All good steps!

P.S. what are the greyish spacer (?) rings in your photo used for? height limiters on a photo tube? I see that their heights are according to a series 1,2,4,...etc, to enable all height combinations?

One has to raise a 'normal' KPL eyepiece in order to convert it into a projector lens to use it to project an image directly onto the camera sensor.
Raising it just a few mm will do. However as the magnification of the projection is also controlled by the height of the eyepiece I used a combination of the rings to fine tune the field of view coverage.
Rings are 2.5mm, 5mm, 10mm, 15mm and 20mm in height.

Please tell if you see any visual advantage of the Mipro. These lenses I have seen here and there on eBay, but ignored them for the time being (prices being the main reason).

There are two advantages to it in my book.
The main advantage is that it projects a parallel infinite image - that means that the camera can be placed at any height over it, removing the tedious and variable task of setting up the camera at the exact focus point every time after having removed it.
The second advantage is that with this projector eyepiece the camera requires a lens, this eliminates the dust problem I was having when using a raised 'normal' KPL as a projector lens that projected directly on the sensor.
As to the quality of the Mipro, I find it comparable to the 12.5x/18 KPL I was using.
As to prices, I picked mine up for around £30 in 2016 (had to look it up), like most purchases on Ebay, patience is a virtue. Put it on your wish list and bide your time.

[Hobbyst46]

Sorting out image problems is frequently done in a series of steps, a good first step would be to match your photos to what you see through the eyepieces. CA can be dealt with later.

OK. I have verified parfocality and focusing, and thought to give it another test with Paracetamol (crystallized on the slide from ethanol). One caveat that I missed at first was that crystallization proceeds on and on long after I though it ended. So, although I ran the stack photo series within less than 2 minutes, there might be some changes as the colorful spot increases continuously. Nevertheless, here is the result, and a single frame I shot afterwards, after focusing on the rim of the spot, using the 10X focusing sight feature of the camera. 10X0.30 160/- (non phase) neofluar objective, and Ph2. No cover slip.

[Hobbyst46]

Here are two more attempts, Paracetamol, 10X0.30 Neofluar, brightfield. Single image. Resized and cropped only.
Somehow I feel that these images lack "luster" (beyond artistic aspects).

My doubts:
1. I could enhance the contrast in photoshop - but is that the only way?
2. Is the sharpness acceptable, given my optical equipment, or is there a vibration effect on these images? if so, looks like I will have to find a way to mechanically isolate the camera.. .