Fig. 1: The red image on the left is a pre-perihelion HST image of
Hale-Bopp taken with the WFPC2 on 23 Sep 1996 when the heliocentric and
geocentric distances were 2.97 AU and 2.95 AU, respectively, and the
solar phase angle was 19 degrees. The blue image on the right is a
post-perihelion HST image of Hale-Bopp taken with STIS on 27 Aug 1997
when the heliocentric and geocentric distances were 2.48 AU and
2.99 AU, respectively, and the solar phase angle was 18 degrees.
For both images celestial North is straight up and East is to the left.
Each image is 10.9 arcsec across, which projects to 23,800 km at the
comet, and a single pixel subtends 99 km at the comet. The nucleus
is at the center of each image.
Click here to see the postscript version of
the above figure.
Fig. 2: Again, the red image is the pre-perihelion data and the blue
image is from post-perihelion. Here we have divided the images in
Fig. 1 by azimuthally-averaged images in order to enhance any asymmetrical
structures in the coma. Strong jets are apparent in both images.
Enhancements (depressions) along a jet indicate that the comet shows
strong temporal variability.
Click here to see the postscript
version of the above figure.
