The GNIRS Integration Time Calculator can be used to determine limiting magnitudes, exposure times, S/N ratios, background levels, etc. for a wide range of source properties, observing conditions and GNIRS configurations. The ITC was used to generate a table of spectroscopic sensitivity estimates. The agreement between ITC predictions and commissioning results on the telescope is good to within 15% from 0.9-3.5um and TBD at longer wavelengths.

The estimated image quality delivered to the instrument is given as part of the observing condition constraints .