LonGSp is a near-infrared grating spectrometer, designed for the 1.5 m Italian Infrared Telescope T.I.R.GO. ... The sky-projected pixel size along the slit is 1.73" and the maximum slit length is about 70., this means that only a 40 pixels stripe of the array is used. ... Read-out and control electonics are the same of ArNICa , based on the IRL System 2 developed by Infrared Laboratories (Tucson - AZ), with the necessary alteration to control slits and grating and for handling spectroscopic data. ...