urn:nasa:pds:context:instrument:eso-la_silla.ntt.sofi 1.4 1.25.0.0 Product_Context urn:nasa:pds:context:instrument:eso.ntt.sofi 2026-07-07 1.4 Removed duplicate Internal_Reference entries from Reference_List. 2025-12-24 1.3 Adding missing "facility" references. Adding missing "telescope" references. 2025-12-24 1.2 Updated schema version. Adding missing "facility" references. Adding missing "telescope" references. 2025-01-02 1.1 Updated schema version. Adding missing "telescope" references. Update instrument type/subtype to use valid CTLI LDD. 2021-12-07 1.0 per RMS, deprecated eso in favor of eso-la_silla urn:nasa:pds:context:telescope:eso-la_silla.ntt instrument_to_telescope urn:nasa:pds:context:facility:observatory.eso-la_silla instrument_to_facility Moorewood, A., J.-G. Cuby, and C. Lidman, SOFI sees first light at the NNT, Messenger 91, 9-13, 1998. SOFI (Son OF Isaac) Imager Spectrometer 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.