| This research reports on the re-commissioning and modification of an advanced National Physical Laboratory pattern prism refractometer made by E. R. Watts and Son in 1946. The research includes exploring of the functions of the instrument assemblies; focusing the telescope and collimator; leveling the prism table, telescope and collimator; and the design and assembly of the illumination system for the collimator slit. After re-commissioning, the instrument was evaluated by measuring the index of refraction of BK7 and F2 glass prisms and results were compared against those provided by the manufacturer of the prisms. The collimator and telescope lens were redesigned using CaF 2 and fused silica optical elements, and the eyepiece of the telescope was replaced by a detector that can detect ultraviolet light so that the instrument can work in the UV spectrum. This modification was needed so that plastic materials for use on NASA's Extreme Universe Space Observatory project could be evaluated. |
