This page is mainly split to Three different section.
Object should appear tall and thin and concave surface should be facing (Direction of light travel) towards the slits or PMT
Correction Lens
The correction lens [LE 5] has a convex-cylindrical surface (radius 170.0 mm) and a concave-spherical surface (radius 230.0 mm).
Both surfaces are coated with a layer of magnesium fluoride to minimize reflectance at 315.0 nm for an incidence angle of 29°. The lens is mounted in the entrance-slit housing at an angle of 29° to the optical axis with the concave-spherical surface facing the entrance slit. The axis of the cylindrical surface is positioned in the horizontal plane to within 1°.