Inferred noise in the MUSE HDFS observation as a function of observed wavelength or redshift for different pseudo-narrowband widths: Δλ_obs = 3.75 Å, Δλ_obs = 8.75 Å, Δλ_obs = 12.50 Å, and Δλ_obs = 17.50 Å. Skylines result in increased noise in some spectral ranges. The vertical dashed line indicates the position of Lyα at z = 4.8, which is located in a spectral window with lower noise. The throughput of MUSE is at its maximum of ∼40% at ∼ 7200 Å (e.g., Richard et al. 2019).