Optimization of LETG/HRC-S spectral extractions

We describe a new calibration of the wavelength-dependent cross-dispersion profile of LETG/HRC-S spectra, which allows the use of a narrower spectral extraction region. Background is reduced by ~20% with negligible loss of X-ray signal. Some features of this work are improved 0th order positions, corrections for a fixed pattern of wiggles and slight time-dependent tilts in dispersed spectra, and an updated calibration of the enclosed energy fraction (EEFRAC) that includes the effects of asymmetric cross-dispersion profiles.