Centric diatom from Wakura Beds, Japan or how quick do diatoms travel?

[MicroBob]

it should not be very sensitive to the coverslip thickness.

Hi Doron,
I would think so too. I really don't have an idea what the difference might be. What I observed was that some of my objectives did better than others but the simple 100:1 achromat did well. Perhaps it really is related to the diatom itself. The round and ttriangular and square diatoms often have a second, finer structure inwards from the coarser outer one. This layer might simply be absent on your diatom or it might just not be the precisely same species. If I find some time I can make a strew slide from Wakura beds and look what I will observe.

Bob

[hans]

... But, setting aside this point, I wonder about the "-" design vs the "0.17" design.

I don't remember the source but read somewhere a possible reason to specify cover glass thickness for an immersion objective is due to differing dispersion characteristics of immersion oil vs. borosilicate glass. So even if the refractive index is matched perfectly at one wavelength varying cover glass thickness can still introduce chromatic aberrations.