FIG. 24.

Signal-to-noise ratios required to quantify the flux within 3σ in the center of the absorption band (defined as the lowest flux level) for the O₂ A band, 1.06 μm dimer feature, and the 1.27 μm feature. The SNR required for this level of precision decreases as resolving power decreases because the flux is averaged over fewer wavelength bins, leading to an increase in the lowest flux. This decrease in required resolving power occurs for all three absorption features, though the trend is most apparent for the O₂ A band, as it has the narrowest spectral shape of the three features considered here.