On average the signal levels in the wings are on order 2 × 10⁴ DN = 3 × 10⁷ e⁻ per 0.0215 nm pixel. Those in the emission cores are a factor of 3–4 smaller. Figure 16 Left: GOES-16 estimated signal for a 3-second integration using SURF calibration measurements. Weighting functions used to calculate MgII_EXIS (Sect. 5.3) are superimposed on the spectrum. Right: Noise contributions for a 3-second integration. Solid lines represent random components. The ±1DN uncertainty in the sum dark current + detector offset is dashed. Negligibly small random terms arising from particle backgrounds and scattered light are not shown.