** Next:** 11.2.3 Application of Calibrations
** Up:** 11.2 High-Dispersion Absolute Flux
** Previous:** 11.2.1 Ripple Correction

The high-dispersion inverse sensitivity curve is defined to be the
product of the low-dispersion inverse sensitivity curve and a
wavelength-dependent high-to-low absolute calibration function
(Cassatella 1994, 1996, 1997a, 1997b):

*C* = *n* / *N*

where *C* is the calibration function, *n* is the low-dispersion net
flux normalized to the exposure time, and *N* is the high-dispersion
ripple-corrected net flux also normalized to the exposure time. The
calibration function represents the efficiency of high-dispersion
spectra relative to low-dispersion and was determined empirically using
pairs of high- and low-dispersion spectra obtained close in time so as to
minimize the effects of the time-dependent sensitivity degradation.
*C* is represented functionally as a polynomial in the
following form:
where is wavelength in Ångstroms. The coefficients used
in the calibration function are given in Table 11.11.

**Table 11.11:**
High-Dispersion Calibration Function Coefficients
Coefficients |
LWP |
LWR |
SWP |

*C*_{0} |
251.383956 |
251.383956 |
1349.8538 |

*C*_{1} |
-0.053935103 |
-0.053935103 |
-2.0078566 |

*C*_{2} |
0.0 |
0.0 |
1.10252585e-3 |

*C*_{3} |
0.0 |
0.0 |
-2.0939327e-7 |

** Next:** 11.2.3 Application of Calibrations
** Up:** 11.2 High-Dispersion Absolute Flux
** Previous:** 11.2.1 Ripple Correction
*Karen Levay*

*12/4/1997*