comet observations + comet spectrum during night 18/19 july

During this clear night is started with comet observations on BRIXIIS-I observatory with the 0.4-m f/3.8 AG 16 telescope: comets that are observed are: 21P, 37P, 29P, C/2017 M4, C/2018 C2C/2017 S3 and P/2018 L4. Also simultane i started with spectra observation on BRIXIIS-II observatory with C11 + L200 spectrograph on comet 21P and comet C/2017 S3. First i saw taht it could not easy to observe 21P with the spectrograph. Comet 21P was barely visible in the guiding camera, but i started anyway with 4x 1200 sec exposures and see what i can do with this images of the spectrograph. After these observation, comet C/2017 S3 was just above the tree that block my view and i started with 2×1200 sec. This comet was better to observe (magnitude +1 in comparison with 21P).  spectrum and how processing is done, can you see on page: spectrum comet C/2017 S3