Description
The New Robotic Telescope (NRT) will be a 4-metre-class fully robotic telescope to be sited on La Palma. NRT will primarily be used in time-domain astrophysics, and, as such, there is a requirement for rapid response and high-efficiency observing and instrumentation. We have, therefore, developed a novel slit-based spectrograph design with no moving parts. The primary design feature is a beamsplitter, where a small fraction of light will be reflected towards a dedicated acquisition detector. The rest of the light will pass through the system for spectroscopy with a second detector. We present the initial laboratory testing results of various coated planes as beamsplitters, including dichroic coatings and anti-reflection coated options. Preliminary tests were completed to assess the stability of the LEDs used as test light sources over time, this included monitoring the voltage and room temperature over extended periods. This allowed for reliable throughput tests to be conducted with four off-the-shelf beam samplers across a total wavelength range of 4300-7900Å.
