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Littrow Spectroscope
- 1911
"The collimators and observing telescopes have apertures of 50mm., and focus by rack and pinion. Two 60 degree prisms of heavy flint glass and of 70mm. side are furnished with the instrument. The mirror may be used in…
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Small Comparator
- 1911
An "instrument intended for measuring spectra photographs, gratings, divided scales, or such objects which can be focused by the microscope and will allow rapid measurements of the highest possible accuracy." The design…