Each NPO250 model with F-number of 3.9 and focal length of 270 mm uses an original optical configuration with two independent optical channels.
The collimating and focusing mirrors are off-axis parabolic, that ensures high spectral resolution and excellent image quality.
Besides selection of two spectrum intervals by grating rotation, the instrument allows quick manual gratings change-over in each channel.
NPO250-2 is a completely automated spectrograph with two independent channels.
NPO250-2M is a two-channel spectrograph with manual control.