An arrangement of three Stictodiscus californicus from Santa Maria, California. There is no makers name on the label however it is very similar to slides by WA Firth, although Barbour brothers ones are also very similar. For now I’ve put it down as WA Firth but with a question mark. Dated November 1882. Olympus BHB microscope using 450nm LED light. 40x Olympus DPlanApo UV NA 0.85 objective, coverslip thickness set to 0.17mm. Olympus Aplanat Achromat condenser, slightly oblique lighting. 2.5x Olympus NFK photoeyepiece. Monochrome converted Nikon d850 camera. 16 images stacked in Zerene (Pmax).
The coverslip on this one was very badly damaged, with multiple cracks present. Given that these cracks were very close to the diatoms I decided not to use oil immersion, but instead used a high NA dry objective (40x Olympus DPlan Apo NA 0.85).