(larger JPG file; 85k)
Since a few days, Comet Hale-Bopp can again be observed from Mauna-Kea, as its apparent position in the sky is moving away from the Sun.
This image of Comet Hale-Bopp is a composite of 2 frames obtained by Jun Chen on Feb.7, 1997. She used the 8192x8192 pixel CCD mosaic built by the Institute for Astronomy, installed on the 2.2m telescope of the University of Hawaii telescope at Mauna Kea through a VR very broad band filter. On this image, North is up, East is left. This image is a 8x7 arcmin. piece from the larger mosaic; the whole comet is much wider than the small region shown here; the gaps between the CCDs forming the mosaic appear as broad black regions. The original image has not been flat-fielded: some dust rings are still visible.
The central region of the comet was extracted from a CCD image obtained with a very short exposure time (0.3sec) in order not to saturate the very bright object; it was combined with a much longer exposure (10sec) on which all the central region is saturated, but which shows the fainter, extended coma of Hale-Bopp (the boundary between the two images is slightly visible as a small discontinuity encircling the central coma). The jet structure has been enhanced by subtracting a model of the comet built using a 1/r profile and a mean profile of the South-East quadrant of the comet; this is the cause of the small dark spot next to the center of the comet and of the thin rings that are visible in the lowest surface brightness regions of the coma. The jets are pointing to the Sun, which is in the direction of the top-right corner.
Jun Chen and her group (Dave Jewitt, Chad Trujillo and Jane Luu) were using the rest of the night searching for very faint, distant minor planets in the Solar System. The images were processed by Olivier Hainaut at the IfA.
If you want to observe Hale-Bopp yourself (you should, it is beautiful), maps and ephemerides are available on this site.
Sun Feb 9 16:36:24 1997