The collimator slit with spring loaded jaws is of a new & robust design which ensures retention of the initial accuracy. The graduated prism table support, 180mm diameter, is divided in degrees; the vernier, reading to 0.1 is fixed to the telescope arm. This arrangement permits easy estimation to 0.05 from the conveniently positioned vernier scale. . The fully adjustable prism table 75mm dia. is engraved with concentric rings, which facilitates correct location of a prism & has two screwed holes for the attachment of the prism & grating holder, to accommodate a prism upto 25mm high. Large diameter clamping knobs are fitted for movement control & fine adjustment is provided for the telescope. All bright parts are chromium plated with the base & tube in synthetic hammer finish.