A search for monochromatic light towards the Galactic Centre

A region 140 square degrees toward the Galactic Centre was searched for monochromatic optical light, both pulses shorter than 1 sec and continuous emission. novel instrument constructed that acquires spectra of every point within 6 second, able to distinguish lasers from astrophysical sources. The system consists a modified Schmidt telescope, wedge prism over 0.28-meter aperture, fast CMOS camera with 9500 x 6300 pixels. During 2021, total 34800 exposures were obtained analyzed sources, sub-second in time. No light found. benchmark laser 10-meter aperture located 100 years away would be detected if it had power more ~60 megawatt during sec, 1000 away, 6000 MW is required. This non-detection adds previous SETI non-detections 5000 nearby stars all masses, Solar gravitational lens focal points Alpha Centauri, all-sky searches broadband pulses. These non-detections, along those pulses, constitute growing desert domain.