Scale: 150mm diameter circle is fixed, the table and telescope movements are completely independent of each other. Both movements can be read to 30 sec. of arc by means of double ended verniers. Both rotations have fine adjustment screws, and release of a clamping screw enables coarse adjustment to be made by hand.
Collimator: mounted on fixed and pillar and fitted with 178mm focus achromatic objective, 28mm clear aperture. Also fitted is a unilaterally adjustable slit 7mm long.
Telescope: mounted on moveable pillar and fitted with 178mm focus achromatic objective, 28mm clear aperture. Also fitted is an x 10 Ramsden eyepiece and glass cross line graticule. Both the telescope and the collimator have rack and pinion focusing.
Prism table: the table is marked with lines to assist placing the prism with respect to the table levelling screws, and has interchangeable clamping units for the prism and a diffraction grating.
Standard accessories supplied: • 1 x prism clamp • 1 x diffraction grating holder • 1 x Hand magnifier • 1 x tommy bar for adjusting optical axes • 1 x plywood case
Comprehensive setting up instructions also provided. Supplied WITHOUT prism. E8A46383
£513.26 Findel… Growing education for generations 329
B. Spectroscope
The performance of this ultra-low cost spectroscope is comparable with instruments typically costing much more.
It uses a CD or DVD as a reflective diffraction grating and clearly shows Fraunhofer lines in the spectrum arising from natural light – and distinctive emission bands from artificial sources such as sodium lamps.
Differences between fluorescent lighting tubes – e.g. white light or ‘warm’ light types – can be easily identified by their distinctive emission bands.
The spectroscope is made from virtually indestructible polypropylene and supplied in flat pack form – taking about 30 seconds to assemble. It comes with a free CD but can be used with any CD (or a DVD for higher resolution).