Heavy cast aluminium alloy base integral with collimator tube support. Both the collimator and telescope have 175mm focal length and 25mm aperture object glass at their one ends. The collimator has precision slit and telescope an 8X Ramsden’s eye-piece at their other ends. Focussing is done by helical action device. The scale 175mm diameter is divided in degrees and is read to 0.1 degree (6 minutes of arc) with the help of vernier fixed to the telescope arm. The scale can be rotated through 180° and locked in any desired position. The telescope has both the coarse and fine adjustment for exact readings. The prism table, 75mm diameter, has screwed holes for fixing prism and grating holders. It has lines marked to assist placing of prism with respect of table levelling screws. Prism holder can accommodate prisms upto 38mm high. Supplied with prism holder, grating holder and tommy bar for adjustment of optical axis.

This instrument is designed for high performance student use. It has cast aluminium alloy main structure. The collimator tube is mounted on the fixed pillar and telescope tube on the moveable. Both the collimator and telescope have 175mm focal length, 32mm clear aperture object glass at their one ends. The collimator has a precision slit 6mm high and telescope has Ramsden’s eye-piece 15X at their other ends. Both collimator and telescope have rack and pinion focussing and means for levelling their axes and squaring them to the axis of rotation.

The scale 127mm diameter with protective shield is fixed to the telescope movement and the prism table is attached to the double ended vernier which reads to 1 minute arc. Both telescope and table can be rotated independantly by hand about the same vertical axis. These can be clamped at the desired positions and adjusted precisely with the help of fine adjustment screws.

Prism table is marked with lines to assist placing the prism with respect to the table levelling screws and has screwed holes for fixing prism and grating holders. Prism holder can accomodate prisms upto 38mm high. Supplied with prism holder, grating holder, magnifier glass, tommy bar for adjustment of optical axis and dense flint glass prism, equilateral 32x32mm. In plywood case.