A bstrocf-Measurements of the visible light obtaining quantitative data difficult. In this paper, we discuss emission from dense, weakly non-ideal Plasmas efforts to measure the average plasma temperature by using have been Performed On the the relative line ratio method. The results using this electrothermal launcher device "SIRENS". The technique are with the results o~conduc~vity, h a plasma is created by the ablation of a Lexan insulator in the source, which then flows through a flux, and mass loss methods for deducing temperature. cylindrical barrel which serves as the material sample. Visible light emission spectra have been observed both in-bore and from the muzzle flash of the barrel, and from the flash of the source.Due to high plasma opacity (the plasma emits as a near blackbody) and absorption by the molecular components of the vapor shield, the hotter core of the arc has been difficult to observe. Recent measurements along the axis of the device indicate time-averaged plasma temperatures in the barrel of about 1 eV for lower energy shots, which agree with experimental measurements of the average heat flux and plasma conductivity along the barrel. Measurements of visible emission from the source indicate time averaged temperatures of 1 to 2 eV which agree with the theoretical estimates derived from ablated mass measurements and calculated estimates derived from plasma conductivity measurements.