Read by two opposite verniers reading to one minute of the arc. The objectives used in telescope and collimators are achromatic and provided with rack and pinion focusing arrangement. Telescope arm and prism table are provided with fine and coarse adjustment. The prism table is provided with three leveling screws
and is engraved with concentric ring and lines.
The scale and verniers are of stainless steel and are machine divided. Cover plate protects the scale from dust and carries two transparent windows for verniers. The instrument is finished
in pleasing and smooth duco colour and other necessary parts are chromium plated.
With prism clamping device and diffraction grating stand in polished wooden case:
a) 5 dia circle reading one minute ,
b) 6 dia circle reading one minute,
c) 6 dia circle reading 30 seconds,
d) 7 dia circle reading 30 seconds,
e) 9 die circle reading 30 seconds,
f) 10 dia circle reading 30 seconds