Near-UV and optical spectroscopy of comets using the ISIS spectrograph on theWHT

We present an analysis of long-slit cometary spectroscopy using the dual-arm Intermediate dispersion Spectrograph and Imaging System spectrograph on the 4.2 m WHT. 11 comets were observed over two nights in 2016 March and we detected the OH (0-0) emission band at 3085 Å in the spectra of five of these comets. Emission bands of the species NH, CN, C3, C2, NH2 and [O I] were also detected. We used Haser modelling to determine molecular production rates and abundance ratios for the observed species. We found that our average abundances relative to OH and CN were generally consistent with those measured in previous studies.