Relative brightness of some comet SL9 fragments (July 12, 1994)
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Olivier Hainaut and Richard West
European Southern Observatory

July 12, 1994, 12:00 UT


The relative brightness of cometary fragments A - L and P has been
measured on a 15 min, 2000 x 2000 pix CCD exposure, obtained through a
standard R filter with the EMMI instrument at the ESO 3.5-metre New
Technology Telescope on July 11.08 by F. Mirabel, P.-A. Duc, S. Chaty
(Service d'Astrophysique, Commissariat a l'Energie Atomique, Saclay,
France).

The peak intensity above sky is that of the brightest pixel in the
object. The sky subtracted flux was integrated over circular apertures
with diameters 5 and 10 arcsec, respectively, centered by cursor on
the objects.  The sky level was obtained as the median of a nearby,
approx. 50 x 50 pixel empty region. The values are given relative to
the brightest fragment (G) in the observed field.


Fragment    Peak     Aperture Integrated
         Intensity   5 arcsec  10 arcsec

   A       0.30        0.12       0.15 
   B       0.38        0.24       0.28  
   C       0.31        0.23       0.26  
   D       0.28        0.14       0.18  
   E       0.57        0.45       0.46  
   F       0.47        0.30       0.32  
   G       1.00        1.00       1.00    
   H       0.71        0.65       0.73  
   K       0.91        0.89       0.87  
   L       0.68        0.64       0.73  
   P       0.40        0.39       0.56