False color intensity, line width, and line ratio maps of the extended
solar corona during the period August 19 to September 1, 1996.  The
false color scale progresses in the intensity maps from black (low
intensity) to red to white (high intensity).  In the line width maps,
the color scale progresses from black (narrowest lines) to blue to
red to yellow (broadest lines).  In the O VI intensity ratio map,
green represents a high value of the 1032 to 1037 intensity ratio
(i.e., outflow speed below about 100 km/s) and red represents a low
value of the ratio (outflow speed above about 100 km/s).

The UV corona is imaged between 1.5 and 3.8 solar radii, and the
disk of the Sun (at the center of each image) is indicated with a
circle.  Images at a given polar angle were built up by scanning in
steps of 0.1 solar radii, from 1.5 to 2.2 solar radii; steps of 0.2
solar radii up to 2.9; and two additional steps of 0.4 and 0.5
solar radii to reach 3.8 solar radii.  A complete raster at one of
the 12 polar angles scanned was performed in approximately 10 hours.
Note the wider line profiles in the darker polar coronal hole
regions and the faster outflow speed over the poles, as indicated
by low ratios of the O VI 1032 to 1037 intensity.

(Antonucci et al. 1997, ESA SP-404, p. 175)