Solar Physics
Contents
of the supplement
Soft X-ray Observation of a
Large-Scale Coronal Wave and its Exciter
Authors: Hugh S. Hudson, J. I.
Khan, J. R. Lemen, N.V. Nitta, & Y. Uchida.
Movies
Movies of Yohkoh SXT Flare-Mode
Partial-Frame Images (Full Resolution).
Movies of Yohkoh SXT Flare-Mode
Partial-Frame Images (Half Resolution).
Movies of Yohkoh SXT Flare-Mode
Partial-Frame Images (Quarter Resolution).
Composite movies with GOES history.
These movies show data from the Yohkoh Soft X-ray Telescope (SXT;
see the instrumentation
paper for full details; external URL not on CD). In brief, SXT takes images
in restricted fields of view during a flare; these are all 64 x 64 pixels but
on-chip summation allows them to be either full resolution (2.46"), half
resolution (4.91"), or quarter resolution (9.82"), with proportional
fields of view (hence the largest FOV is 10'28.5" on a side). Because of
the large dynamic range of a flare image, we often reduce the contrast by
compressing the intensity scale. For the movies shown here, we had deliberately
overexposed the half- and quarter-resolution images in order to bring out faint
features. This results in saturation artifacts (the vertical spikes) not
present normally in the full-resolution exposures. In viewing the movies, be
aware that the sampling rate changes with time as the spacecraft changes
operating modes. In the movie sequences above, one such change occurred between
07:59:20 UT and 08:01:28 UT, just as the wave was beginning! This may fool
the eye into mis-estimating velocities. In addition to this, please be aware of
the effects of exposure-time changes in the full-resolution sequences.
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