It’s too warm today to spend much time on the microscope, but I wanted to share the results of a little experiment. Having recently discovered that the Leitz 100x Pl Apo objective had pretty good UV transmission at 365nm, I thought I would give the 63x NA 1.40 a go as well, in combination with a Watson Quartz Cassegrain dark ground condenser, with the idea being to produce a circular oblique illumination setup (due to the high NA of the objective). Here are the results of the initial test. A little less formal than usual, but something to be returned to later.

On the Thum slides, he used large disc shaped diatoms at either side of the main subject to help with locating for viewing. It is one of these disc shaped diatoms that is the subject today. Here’s a stack of 7x images taken using 365nm light on my Olympus BHB with the 63x Leitz Pl Apo NA 1.40 objective (resolution reduced for sharing here).

The lighting has produced a nice 3D effect (even though the condenser is a dark ground one, the high NA of the objective means the images isn’t dark ground). Here’s a crop at original pixel resolution.

There is certainly lots of nice detail in the image. Refocusing on the edge of the diatom gave the following (single image, no stacking this time).

And again a crop of the image at original resolution.

I save my images as jpegs in the camera, and then if I am stacking use them to create a 16 bit TIFF file for further work. Interestingly the single image of the edge of the diatom shows a lot more artifacts (and was just processed as the jpeg) vs the stack even though everything was just saved a jpeg in the camera. I may try saving as BMP files in camera in future, especially when dealing with these UV images which show up all the small features and noise. The slide itself came from the Antiques Microscope ebay shop (see here), and here’s the full arrangement.

And the slide itself.

I shall return to the slide to look at the main subjects when it is a bit cooler here. In the mean time thanks as always for reading, and if you’d like to know more about my work I can be reached here.