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IAUC 6431: Cyg X-1; DN Gem; C/1996 N1

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                                                  Circular No. 6431
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
Phone 617-495-7244/7440/7444 (for emergency use only)


CYGNUS X-1
     L. Piro, Istituto di Astrofisica Spaziale (IAS), CNR, Frascati;
R. C. Butler, Agenzia Spaziale Italiana; G. Boella, Istituto di
Fisica Cosmica e Tecnologie Relative (IFCTR), Milan; L. Scarsi,
Istituto di Fisica Cosmica e Applicazioni dell'Informatica (IFCAI),
Palermo; J. A. M. Bleeker, Space Research Organization of the
Netherlands (SRON), Utrecht; A. Parmar, Space Science Department,
European Space Agency, Noordwijk; L. Chiappetti, IFCTR; B. Sacco,
S. Giarrusso, and A. Santangelo, IFCAI; F. Frontera and D. Dal
Fiume, Istituto Tecnologie e Studio delle Radiazioni Extraterrestri,
Bologna; E. Costa, IAS; R. Jager and J. Heise, SRON; and P. Giommi,
SAX Scientific Data Center, Rome, report on behalf of the SAX Team:
"BeppoSAX successfully performed its first scientific observation
by pointing at Cyg X-1 from June 22 to 25.  All of the instruments
performed nominally and showed that the source remains in its high
state with a soft spectrum in the energy band 0.1-10 keV with an
intensity of about 1 Crab.  Below 10 keV, the spectral shape is
similar to that observed by ASCA (IAUC 6415).  A hard component
with a flux of about 0.3 Crab is visible in the energy range 10-300
keV.  The source intensity is variable with a peak amplitude of
about 40 percent at low and high energies.  Typical intensities
observed by the different instruments are:  LECS (0.1-10 keV), 350
counts/s; MECS (1-10 keV), 430 counts/s; HPGSPC (4-120 keV), 140
counts/s; PDS (15-300 keV), 65 counts/s; WFC (2-30 keV), 170
counts/s.  Corresponding fluxes, in units of 10E-8 erg cmE-2 sE-1,
for various ranges are: 0.1-2 keV, 1.3; 2-10 keV, 1.1; 4-34 keV,
1.1; 15-300 keV, 0.9; 2-30 keV, 1.6."


DN GEMINORUM
     A. Retter and E. M. Leibowitz, Wise Observatory, Tel Aviv
University, write:  "We performed CCD R photometry of the classical
nova DN Gem during 14 nights in 1992 and 1993, and I photometry
during 17 nights in 1995-1996.  The light curve is modulated with
the period 0.12785 +/- 0.00005 day, with a peak-to-peak amplitude
of 0.06 mag."


COMET C/1996 N1 (BREWINGTON)
      Visual m1 and coma-diameter estimates:  July 6.21 UT, 9.2,
4'.5 (C. S. Morris, Pine Mountain Club, CA, 0.26-m reflector);
6.92, 9.1, 6' (J. M. San Juan, Ciudad Real, Spain, 0.44-m
reflector); 7.40, 10.0, 5' (P. Camilleri, Cobram, Victoria,
Australia, 20x80 binoculars); 8.18, 9.6, 3'.5 (A. Hale, Cloudcroft,
NM, 0.41-m reflector).

                      (C) Copyright 1996 CBAT
1996 July 8                    (6431)            Daniel W. E. Green

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