Boehnhardt, H. et al A&A 341,912-917, 1999
"The nuclei of comets 26P/Grigg-Skjellerup and 73P/Schwassmann-Wachmann 3"

CCD V and R images were obtained at large heliocentric distances to
try to derive size, rotation, etc.  
  SW3 observations 27--31 December 1994 (before split)
       R=3.03, delta=2.34, phase angle=15d egrees
Images showed small coma (~12,000km) and tail in anti-solar direction so
comet not totally inactive.  Derived an UPPER LIMIT for the radius
of 1.1km and a solar V-R color.  Determined only 4% of surface active.
     R(1,1,0)=16.85; V(1,1,0)=17.33
    [R(1,1,0) is R mag at helio=1au, geo=1au, phase=0]

=====

Lisse, C. M. et al ApJ 496, 971-991, 1998
"Infrared Observations of comet by COBE"

Used the DIRBE data and detected 4 comets, including SW3.  SW3 was the
faintest (by far) comet observed.  Uniformly bright over a large number
of days so no lightcurve info.  Observations 22Paril -- 26 May, 1990; V=10.5--9.
Derived T=307+/-20 (black body would be 282).  Unresolved point source.
   R=1.07; Qdust=120 (kg/sec); Qgas<3e28 (mol/sec); dust/gas > 0.12;
     Mtail=1e10 (kg)
Also: did not detect Encke despite it being comparable magnitude.

=====

Crovisier, J. et al A&A 310, L17-L20, 1996
"What happened to comet 73P/Schwassmann-Wachmann 3?"

Radio observations (Nancay) of SW3 just PRIOR to the proposed splitting
date.  Observations were 30 August -- 18 September and 15 October -- 
1 November 1995 (splitting 24 October and 1 December according to Sekanina).
20x increase in OH production but the OH and visual production evolutions
are different -- the OH increase seems to be much steeper than the
visual brightness increase and the OH brightness peak occurs one month
earlier than for the visual brightness.  The start of the OH outburst
is ~45 days PRIOR to the split.  There was not a single outburst but
sustained activity.

The active area derived during the outburst was 30 km^^2 which is
incompatible with the small nucleus size above or the 2km derived
by Sekanina. 

OH production rates are given in Table 1 and range from < 2.8e28 to
22.2e28 mol/sec.

=====

Fink, U. and Hicks, M. D. ApJ 459, 729-743, 1996
"A Survey of 39 Comets Using CCD Spectroscopy"

Based on spectra from 0.55 to 1.0 microns (so O (1D) for H2O).

Observed SW3 on 28 Feb 1990 with R=1.44 Delta=0.75
Details of fluxes given
Haser model production rates
   Q(H2O) = ~4.2e27         (at 1au this is Q(H2O)=~1.0e28)
   Q(C2)  = <0.3e25
   Q(NH2) = <0.08e25
   Q(CN)  = ~1.3e25
==> Q(H2O)/Q(CN) = 323

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