This is an echelle simulator for iSHELL (Immersion Grating Echelle Spectrograph) at the NASA Infrared Telescope Facility (IRTF). It employs a set of ab-initio grating equations and simplified parameters that are accurate enough to describe the overall behavior of the cross-dispersors and the gratings. Developed by Sara Faggi, Geronimo Villanueva and Michael Mumma at NASA-GSFC.
Setting:       Upper-wavelength [um]:

Slit [arcsec]:    Spectral unit:   Flip y-axis




Transmittance spectrum - Download transmittances