Grating/Camera configurations:

Resolving power:
(λ/Δλ)

Typical uses:
(...and limitations)

The wavelength coverage is about one-third of that of the low resolution mode (e.g., short camera + 32 l/mm grating) and so three or more settings are required to obtain full wavelength coverage at 1-2.5µm. The positioning of the orders depends on the grating central wavelength, so in some grating settings one order may cross the small central patch of bad pixels. If this is likely to pose a problem the user should contact a member of the GNIRS science team.

Fig. 1: Cross-dispersed spectrum of the argon lamp obtained with the 111 l/mm grating set to 1.53µm, short blue camera, and 0.3 arcsec wide slit. Lines can be seen in orders 3-9 (left to right). Wavelength ranges covered are 1.95-2.13, 1.46-1.60, 1.17-1.28, 0.97-1.06, 0.83-0.91, 0.73-0.80, and 0.65-0.71 microns, respectively. Note how the orders are much more vertical on the array than when full spectra coverage is obtained in one setting (eg, using the 32 l/mm grating and the short blue camera).