The NRT will perform fast follow-up observations of transients in the new era of multi-wavelength synoptic surveys. The telescope design specification allows an operable wavelength range of 300 – 2400 nm, while delivering an image quality not exceeding site seeing + 0.2 arcseconds in terms of 80% diffracted encircled energy. The time-to-target requirement following an alert is 30 seconds and as such the instrumentation should allow the object to fall onto the detector FOV within the blind pointing accuracy of the telescope (10”x10”; 99.9% of the time minimum).

 

The instrumentation for the NRT will be stable, efficient and cater to the needs of the time-domain community. Light from astronomical sources can be probed in six dimensions: through two polarisation states, temporally, with respect to wavelength dependence, and intensity in the two spatial directions as projected on the sky. A complex modern instrument may probe all dimensions, however these require large amounts of optics and tend to lead to poor overall instrument throughput. Such a combined instrument would not fit into the instrument envelope proposed for the NRT. Hence, imaging, spectroscopy and polarimetric measurement systems have been designed independently. Based on an analysis of the science case we are proposing a two generation instrumentation plan for the NRT, with the possibility of including a wide-field imager in addition to the proposed first and second generations below.