SOFI (Son of Isaac) is the infrared spectrograph and imaging camera on the NTT.  The
instrument is equipped with a Hawaii HgCdTe 1024x1024 array with squared 18.5 micron
pixels, sensitive to light within 0.9-2.5 micron range. The peak quantum efficiency
is 65%, the gain is about 5.4 e/ADU, and the read out noise is about 2.1 ADU. The
array is linear to less than 1.5% for signal below 10000 ADU.

The instrument offers the following observing modes:

- Imaging with plate scales of 0.144, 0.273 and 0.288 arcseconds/pixel using broad
and narrow band filters in the wavelength range 0.9 to 2.5 microns.

- Low resolution (R=600) and medium resolution (R=1200-1500), 0.93-2.54 micron
spectroscopy with fixed width slits of 0.6, 1 and 2 arcseconds.

 - 0.9-2.5 micron imaging polarimetry.

- High time-resolution imaging in burst and fast photometry mode with integration
times of the order of a few tens of milliseconds via hardware windowing of the
detector array.

Slits (arcsec):   2 x 290    1 x 290   0.6 x 290

Grisms:

Grisms         Order   Dispersion   Resolution    Wavelength Range
GB Grism Blue  1        6.96        1000          0.95-1.64
GR Grism Red   1       10.22        1000          1.53-2.52
HR Grism       3        4.63        2200          2.00-2.30
HR Grism       4        3.44        1500          1.49-1.81
HR Grism       5        2.71        1400          1.20-1.28
HR Grism       6        2.32        1400          1.17-1.24
HR Grism       7        1.87        1400          0.89-0.93
HR Grism       8        1.58        1400          0.86-0.95
(resolution shown for 0.6" slit)

Note:  SOFI is called Son of Isaac because it was developed and built shortly 
after the instrumental study of ISAAC, the Infrared Spectrometer And Array Camera
built by ESO for use at the VLT.

Reference:

Moorewood, A., J.-G. Cuby, and C. Lidman, SOFI sees first light at the NNT, Messenger
91, 9-13, 1998.