Central Bureau for Astronomical Telegrams
IAUC 3945: SS Cyg; QSO 0957+561; Poss. Occns BY SATURNIAN MAGNETOSPHERIC RINGS
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Circular No. 3945
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-495-7244/7440/7444
SS CYGNI
R. S. Polidan and J. B. Holberg, Lunar and Planetary Laboratory,
University of Arizona; A. V. Holm, Computer Sciences Corporation:
and J. A. Mattei, American Association of Variable Star
Observers, write: "Coordinated Voyager far-ultraviolet (50-170 nm)
and International Ultraviolet Explorer (120-320 nm) observations of
the cataclysmic variable SS Cyg during two outbursts are planned
for the coming months. Analysis of AAVSO data obtained since 1980
suggests the following dates for the beginnings of the outbursts:
1984 July 1 and Aug. 25 (with an uncertainty of +/- 5 days in each
case). SS Cyg brightens from V ~ 11.8 to V ~ 8.5 during the first
24 hr of an outburst and then declines back to V ~ 11.8 over the
next 7 to 17 days. We encourage observations in other spectral
regions during these outbursts."
QSO 0957+561
R. Florentin-Nielsen and K. Augustesen, Copenhagen University
Observatory, telex: "Continued photographic photometry shows that
component B of the double quasar has been brightening by ~ 0.3 mag.
This brightening resembles a similar variation in component A in
1982, indicating a difference in light travel time of Delta-t = 1.6 yr.
Observers are urged to perform further photometry between now and
the end of the year in order to improve the accuracy of Delta-t, which
is a measure of the distance to the QSO. The present value of At
gives an upper limit to the Hubble parameter of 125 km s**-1 Mpc**-1."
POSSIBLE OCCULTATIONS BY SATURNIAN MAGNETOSPHERIC RINGS
M. C. Pande, Uttar Pradesh State Observatory, Nainital,
communicates that H. S. Mahra, V. Mohan, A. K. Pande and B. B. Sanwal
observed possible occultations of SAO 158763 by the magnetospheric
ring system of Saturn (Mink 1983, A.J. 88, 559) on May 12.
Observations with the 1.04-m telescope, using a B filter, showed
several dips during 20h52m-21h28m UT, with prominent dips of 0.23,
0.16, 0.16, 0.33 and 0.27 mag at 20h53m5, 20h57m8, 21h15m2, 21h17m4
and 21h26m0, respectively. The features are in accordance with
occultations by the supposed ring at 19 Saturnian radii. No
prominent dips were observed during May 13d14h27m-13d16h30m UT.
Corrigendum. The name of principal investigator Vasundhara
was accidentally omitted from the report on IAUC 3941.
1984 May 30 (3945) Brian G. Marsden
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