Figure 1 from the Science paper: HST images of Hale-Bopp on 8 different
dates. All images were interpolated to the same spatial scale of 470
km/pixel (each image covers a distance of ~33,000 km at the
comet), normalized to the same peak pixel intensity, and are displayed
using the same logarithmic intensity scale. In all images, celestial
north is straight up (vertical direction) and east is to the left. The
image from 26 September 1995 was taken ~60 hrs after a strong dust
outburst and shows a spiral arm wrapping around the nucleus. The images
in the fall of 1996 show multiple jets that are presumably connected to
the activation of multiple vents on the surface of the nucleus. The
image from 7 April 1996 was slightly trailed due to poor tracking.
The same as Figure 1 above, except using a different color stretch so that
the core of the image is a little "bloomed out". Most people find this
version to be a bit more visually pleasing than the one above. However,
the image in Figure 1 is scientifically more valuable.
This is an HST image of Hale-Bopp taken on 26 September 1995 with the
WFPC2 in wide-field camera mode. The frame is about 10 arcsec across, which
corresponds to 47,000 km at the comet. Serendipitously, we caught the
comet only ~60 hrs after a large outburst, and we see the magnificent
spiral arm that results.
This is an HST image of Hale-Bopp taken on 23 September 1996 with the
WFPC2 in planetary camera mode. The frame is 10.9 arcsec across, which
corresponds to 23,360 km at the comet. The shape of the coma at this
time is very different from what was observed a year earlier (in 1995).
Instead of seeing a single strong jet and its associated spiral
structure, the comet now has sprouted several jets, making it look more
like a porcupine.
This is the same data as for the preceeding image, except that we
divided by an azimuthally-averaged Hale-Bopp image. This technique
emphasizes the jet structure and also removes the steep brightness
drop-off as you move away from the nucleus.
In this image, the nucleus is at the very center of the frame, just
below and to the right of the very strong jet near 11 o'clock.
Apparently there was an outburst in this direction shortly before our
observations. Farther out there is another bright region that must be
the remnant of an even earlier outburst. Several weaker jets (at 10
o'clock, 7:30, 3 o'clock, and 1 o'clock; celestial North is at 12
o'clock and East is at 9 o'clock) are also visible. This image
demonstrates graphically that Hale-Bopp's nucleus must be a very
dynamic place. The frame is 10.9 arcsec across, which corresponds to
23,360 km at the comet during these September 1996 observations. The
length of the "white" jet emanating at 11 o'clock is 0.96 arcsec (2050
km at the comet).