Title:	 Spectral characteristics of the solar chromosphere
          
Author: J. Koza

Abstract:  

Context: An open database of the Dutch Open Telescope provides a
         wealth of 2-D ready-to-use Halpha imagery of the solar
         chromosphere suspected of playing an important role in
         heating of the solar corona. Relevant potential of the
         database has not yet been fully exploited.
         
Aims: Employing the Interactive Data Language (IDL) we aim to develop
      reliable "ad hoc" routine capable to transform the Halpha
      filtergrams into 2-D maps of spectral characteristics related to
      wavy processes transporting energy up to the corona.

Methods: We use the filtergrams sampling the Halpha line profile
         usually in five wavelengths (line center, plus minus 0.35
         Angstrom, plus minus 0.7 Angstrom) to construct a coarse
         5-point Halpha profile as a proxy. By polynomial fitting of
         the five wavelength samples the routine infer the line core
         widths, intensities, Dopplershifts, and center-of-gravity of
         the Halpha proxy profiles in each pixel within the field of
         view. In most cases the algorithm uses the polynom of the
         four order. Rarely, it switches in quadratic polynom.

Results: We applied successfully the new algorithm on the 71-min
         sequence of the DOT Halpha images taken on October 19, 2005
         with a 60-s cadence obtaining maps of the spectral
         characteristics of a very quiet chromosphere ready for
         further quantitative analysis. The algorithm needed about 12
         hours to process five 1112 by 818 by 71 datacubes.