Relative transmission spectra obtained with the R150 grating between 570 and 700 nm. The spectrum from R150 observation 1 is shown with black circles, R150 observation 2 is shown with blue triangles, and R150 observation 3 is shown with red squares. Despite being taken at multiple epochs, over three years, the transmission spectra are consistent with one another at the 1σ level. One bin was removed due to being within a strong contaminating line (see Section 6). The data used to create this figure are available.