This erratum concerns the relative spectral response of the HRILya Telescope published in the Solar Orbiter EUI Instrument article (Rochus et al. 2020). It corrects Fig. 24 in Sect. 8.2 of the original manuscript. The published figure was included by mistake, as it showed the response of only part of the optical chain and did not provide the relative response of the entire HRILya Telescope. The difference between the two computed responses is significant because the spectral purity of the band-pass and long-wavelength suppression of the solar continuum was an explicit design driver of the instrument. ? Now at: CIRES, University of Colorado, Boulder, CO, USA The corrected figure, which shows the achieved rejection of longer wavelengths (by many orders of magnitude), is provided in this corrigendum. Figure 1 shows the relative spectral response between 115 nm and 300 nm, predicted by the measurements of all flight components (mirrors, filters, and detector). We note that the peak of the response is shifted by 2:6 nm with respect to the Lyman- rest wavelength as a result of the narrowband focal plane filter, which has its maximum transmittance at 119 nm.
