Title: High Resolution Solar Spectral Variability Near Mg II Measured by HRTS
Author: J. S. Morrill
Affil: E. O. Hulburt Center for Space Research, Naval Research Laboratory,
Washington DC 20375-5352
Email: morrill@shogun.nrl.navy.mil
Authors: K. P. Dere, and C. M. Korendyke
Affils: E. O. Hulburt Center for Space Research, Naval Research Laboratory,
Washington DC 20375-5352
Abstract: The HRTS-9 rocket flight occurred on April 18, 1995 and made both spectral and spectroheliographic UV observation of the solar disk. These observations include high spatial and spectral resolution spectrograms near the Mg II h and k lines as well as spectroheliograms in four FUV passbands and H-alpha. The spectrograms cover the wavelength range 2665 to 2885Å with a spectral resolution of .2Å and a spatial resolution of 1 arc-second along a 900 arc-second slit. The most prominent features in this spectral range include the strong Mg II h and k Fraunhofer lines near 2800Å the Mg I and Si I Fraunhofer lines near 2850 and 2880Å respectively, and the line-blanketed quasi-continuum region.
During the HRTS-9 flight, spectrograms and spectroheliograms where obtained of the quiet sun, quiet limb, plage, and sunspots. The spectra have been corrected for instrumental distortions and we have recently applied an absolute intensity calibration, derived from SUSIM observations. Our initial analysis of these data has focused on the wavelength dependent contrast variation of the observed plage and sunspot compared to the average quiet sun as well as contrast variation within the quiet sun. This analysis has used spectral observations made at a single pointing of the spectrograph slit. Numerous other spectrograms were taken during a slit raster across the observed active region. We are presently applying the various corrections to a portion of these observations in order to derive high spatial and spectral resolution spectroheliograms of the observed quiet and active portions of the sun. In this presentation we will present the results of our recent high resolution measurements of the contrast of the above surface features as well as preliminary high resolution spectroheliograms of specific spectral features.