Here is a list of the recommended names and the appearance of all the nuclei visible in the post-conjunction images, including the press-released January HST image. Hopefully this will help to clear up some recent confusion! John Spencer Brian Marsden Zdenek Sekanina Don Yeomans Paul Chodas February 18, 1994. A GIF-format file of the January HST image of SL9 can be downloaded from JPL (anonymous ftp to "jplinfo.jpl.nasa.gov", directory "news", file name is "sl9hst.gif"). It's also in the Feb 14 issue of Aviation Week. [It is also available in the "ftp/pub/images" directory of this account. -ar.] Here's an identification of the various comet nuclei in this image. The letter designations are informal but we suggest we all use them for consistency from now on, especially in the confusing P/Q region. The names "P" and "Q" (or "8" and "7") should be used if their individual components cannot be resolved. The description proceeds from astronomical East to West, in the same order as the impacts. For orientation, note that the tails stream off to the north-west. The Aviation Week image has north at the bottom. A=21 The easternmost nucleus, visible in the original press realease and the Aviation Week reproduction, but clipped from the GIF image at the left margin. B=20 The eastmost nucleus on the GIF image, displaced north slightly from the general trend. C=19, The next three nuclei, all on the general trend, from east to west. D=18, D=18 is the faintest, E=17 the brightest. These three are followed E=17 by a wider gap. F=16 A relatively faint nucleus displaced north from the general trend. G=15 A bright nucleus colinear with the general trend, quite close to F=16, followed by a wide gap. H=14 A bright nucleus colinear with most of the others, followed by a particularly wide gap. J=13 This nucleus is invisible in the HST image and has apparently disappeared. K=12 A bright nucleus colinear with the general trend, followed by a wide gap. L=11 A bright nucleus colinear with the general trend, followed by a wide gap. M=10 This nucleus is invisible in the HST image and has apparently disappeared. N=9 A faint nucleus about 2/3 of the way between L=11 and Q=7. P=8 A blend of two nuclei, P1 and P2, displaced north from the general trend, resolvable in the HST images. P2=8b A moderately bright nucleus, the east member of the pair, just separable from P1 in the July 1993 HST image. P1=8a The faint nucleus immediately to the west of P2 It is also visible in the July 1993 HST image. Q=7 The brightest nucleus, resolvable as two nuclei, Q1 and Q2, in the HST images. Q2=7b A moderately bright nucleus immediately north of Q1. It is just visible, much closer to Q1, in the July 1993 HST image. Q1=7a The southern, brighter, nucleus of the Q pair. R=6 A moderately faint nucleus to the west of Q=7, colinear with the general trend, and followed by a wider gap. S=5 A moderately bright nucleus colinear with the general trend. T=4 A faint nucleus to the northwest of S=5, displaced north from the general trend. U=3 Possibly visible at the extreme west side of the new HST image, but very faint. V=2, Clipped off the west side of the HST image. W=1 A pictorial representation of the above information follows. Nuclei are designated by ".","o", and "*", in order of increasing brightness. EAST . A=21 . B=20 . C=19 . D=18 o E=17 o F=16 * G=15 * H=14 * K=12 NORTH * L=11 . N=9 o P2=8b } P=8 . P1=8a } *o Q1=7a,Q2=7b } Q=7 o R=6 * S=5 . T=4 . U=3 . V=2 o W=1 WEST WEST ======================= posted 18 Feb 1994, acr.