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37.1 About Flux Calibrations

The concept we discuss here as "flux" has several components. First, is the overall level of the spectrum, or "Has the correct flux scale been applied to the observations?" Second, is the shape of the spectrum, or "Is the curve I see in the continuum real or an artifact?" Finally, there is structure in the spectrum on the scale of a diode's width, or "Is that noise or a bad diode?" The first component has a length scale of tens to hundreds of Ångstroms and is embodied in the sensitivity function for a grating. The second component is incorporated primarily into the vignetting function, which depends on the particular setting for a grating, although other effects can contribute on this scale as well. The small-scale structure, as noted, is seen on diode-sized scales.



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