The f/11 configuration of the telescope and refracting collimator design were defined together to provide a 30 arc-min, well-corrected field of view for imaging and multi-object spectroscopy. The current collimator design is by Epps (run #091197BR), consisting of a field lens and 4 collimating elements. The design parameters for the collimator are:
focal ratio: f/11
focal length: 1648.46 mm (64.90 inches)
output beam diameter: 150 mm (5.9 inches)
number of elements: 5 (all-spherical)
max. fused silica dia.: 323 mm (12.7 inches)
max. CaF2 dia.: 250 mm (9.84 inches)