During 2012 HST STIS longslit spectroscopy of 9 of 10 Galactic planetary nebulae have been successfully taken as part of General Observer Program 12600 for which I am PI. This program marks the first time in astronomy that cospatial longslit spectra of nebulae were obtained from the UV (~1150 A) to the near IR (~9800 A) enabling accurate comparisons of the UV-optical abundance lines across the nebulae. In most cases we measured lines from essentially all significant ionic states of carbon and nitrogen in the photoionized nebulae permitting much more accurate total elemental abundances of C & N to be derived. Planetary nebulae (PNe) arise from the terminal evolution of intermediate mass stars (~1-5 Mo) and are important sources of C & N in the chemical evolution of galaxies. I will show examples of the spectra and the calculations made to derive abundances, then conclude with thoughts on how our results compare with previous more limited spectroscopy with IUE and HST.