Patent ID: 8749781

Claim:
A spectrograph comprising: a housing having a front, a back, a top, a bottom, a first side, a second side and a generally hollow interior; an entrance lens group having a focal length resulting in a focal point, wherein a focal ratio of the entrance lens group is less than f/4, wherein the entrance lens group is located at the front of the housing, wherein the entrance lens group has a diameter of at least 3 mm; wherein the housing lacks any aperture located between the entrance lens and an object providing a light to be observed, and wherein the entrance lens group acts as the only entrance for the light received from the object; a grating located within the interior of the housing; and a viewing port located at the back or sides of the housing wherein no apertures are located between the entrance lens group and the viewing port, and wherein the viewing port is located after the grating along a path of light to be observed, wherein a distance the path of light travels between the entrance lens group and the viewing port is at least 10× or greater the distance between the entrance lens and the focal point wherein the focal point is located on an object field.