This is a set of parts marked simply ‘For Hilger & Watts Spectrometer’. There are three components in a fitted plywood cabinet. Two lenses in holders and a prism secured to a platform. One of the lens mounts is marked ‘GLASS CAM’ which I assume to be a relay optic for the spectrum recording camera, and the other lens mount which is very similar, is marked ‘GLASS COLL.’, which I assume is the collimation optic. The prism, also marked simply ‘GLASS’ appears to have a wedge considerably less than 60 degrees, but it is not indicated.

The free aperture of the two lenses is 49mm. They are not marked with a focal length. The two active faces of the prism are 60mm wide by 38mm tall. The optical centerline of the two lens carriers is approximately 60mm above the base of the carrier. The prism carrier base is approximately 90mm in diameter, and the two lens mount bases are 63mm wide. The ‘Cam’ base is 73mm long, the ‘Coll’ base only 70mm long.

The glass elements are in good condition but the lens coatings are very pale and a bit uneven. Hilger & Watts made at least four different ‘grades’ of spectrometer – these appear to have been parts belonging to one of the mid-grade instruments.

Location MB 0041

Photo set 535