This
apparatus consists of two identical units, each provided with Polaroid disc
mounted in a rotatable mount, with aperture of 25 mm. Both rotatable mounts
have a lever to add rotation and a pointer which traverses a 75mm diameter
brass silvered scale divided into 360°×1. The size is universal and can be
fitted to any size of collimator and telescope.
To fit over the object end of telescope and collimator.
Polaroid
Specifications
Thickness
: 0.1 mm
Type
: Nitrocellulose Polymer
Aperture : 25 mm
Least Count: 1º
