Spectrometer, Intermediate

Reads to 1 minute of arc. 150mm dia. Scale with protective cover and acrylic windows to read verniers is fixed to the telescope movement. The table is attached to double-ended verniers reading to 1 minute of arc with magnifier provided for the purpose. Both telescope and table rotations have fine adjustments. Collimator is on fixed pillar with 175mm focal length achromatic objective of 25 mm aperture and an adjustable slit. The telescope is on a movable pillar with 175mm achromatic objective x 8 Ramsden eye-piece and glass cross-line graticule. Both telescope and collimator have rack and pinion focussing and their optical axes can also be adjusted. Prism table has lines to assist prism placement hand has three leveling screws. With prism clamp, diffraction grating holder and one Tommy bar for axis adjustment, in case.