CoLoRS as the new spectroscopic capability for small robotic telescopes: optomechanical design

The Compact Low-Resolution Spectrograph (CoLoRS) was designed for the 0.7-m Thai Robotic Telescopes (TRTs) network, overcoming challenges such as fast optics, weight limitations, and stringent optical alignment requirements—the 15.2 kg prototype, built with high-precision machining, achieved <20-micron tolerance and <50-micron displacement. Installed on the Nasmyth-1 Port of a TRT at NARIT’s AstroPark in Chiang Mai, Thailand, CoLoRS underwent topology optimization, reducing mass by 55% to minimize torque on the derotator. Its streamlined optical design eliminates moving parts, enhancing stability and enabling simple future robotization. A CMOS camera with a long-pass dichroic mirror took up the duty of guiding and acquisition. With its compact and lightweight design, CoLoRS is well-suited for rapid mass production and deployment across similar facilities, thereby expanding spectroscopic capabilities for small robotic telescopes.