Updated 24-Oct-97 07:30 UT
A more detailed report of this week's activities is available here.
The coronal dimming is evident in the following difference image, which shows the formation of "transient coronal holes" to the northwest and southeast of the bright arcade. The contour shows the zero level in the difference, separating dark (the transient coronal holes) and bright (the arcade).
The coronal dimming can be seen more clearly by measuring the brightness of selected regions and making light curves. An example is shown in the following two images: On the right is an image of the arcade structure, with boxes showing the selected regions of interest. On the left is a graph showing the (normalized) light curves for those two selected regions. The solid line in the graph traces the brightness of the large arcade; the dotted line traces the brightness of the dimming region to the south.
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