TripleSpec4.1 NIR Imaging Spectrograph

Read more about NOIRLab's instruments and other capabilities in the Capabilities brochure.


TripleSpec4.1 was first commisioned on the CTIO 4-m Blanco telescope as ARCoIRIS.  In order to provide greater community access to the instrument, it was decided to move ARCoIRIS to the SOAR 4.1-m telescope during the 2019A semester.  For this move, we installed new optics in the instrument so that the plate scale and spectroscopic resolution would remain unchanged.  TripleSPec4.1 is a cross-dispersed, single-object, longslit, infrared imaging spectrograph, containing no moving parts, and is based on an updated design of the three existing TripleSpec spectrographs installed on the 3.5m telescope at Apache Point Observatory, the 5m Hale telescope at Palomar Observatory, and on the 10m KECKII telescope on Maunakea. TripleSPec4.1 features a fixed slit assembly of 1.1-arcsecs by 28-arcsecs. Spectra cover a simultaneous wavelength range of 0.80 to 2.47 microns, at a spectral resolution of approx. 3500, encompassing the entire z'YJHK photometric range.

TripleSpec4.1 is mounted on SOAR on the IR Nasmyth platform, replacing the OSIRIS spectrograph on one of the side ports.  The instrument is fed by a dichroic, which allows visible light to go to the facility guider.  The guider is able to patrol the full field of view, including the spectrograph target,  So long as there is a suitable guide star in the field of view, this provides faster guiding than the TripleSPec4.1 slit viewer, and therefore better image correction.  The slit viewer is still usable where there are no visible guide stars.


Support for TSpec:

  • TripleSpec4.1 Instrument Scientist: Sean Points
  • Support Scientist: Sean Points

Contact by writing to firstname.lastname at

Updated on January 18, 2023, 9:32 am