Central Bureau for Astronomical Telegrams
IAUC 3149: Cyg X-1 (HDE 226868); Occns BY MINOR PLANETS; 1976b
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Circular No. 3149
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Cable Address: SATELLITES, NEWYORK Telex: 921428
Telephone: (617) 864-5758
CYGNUS X-1 (HDE 226868)
J. C. Kemp, Department of Physics, University of Oregon,
writes: "Our V and U photometry up to Nov. 1977, combined with data
from Lester et al. (1976, Astrophys. J. 205, 855), has produced a
new mean period of 5.60000 +/- 0.00024 days for the interval 1974-77,
with epoch 1976 Jan. 26.745 UT for inferior conjunction of the
primary. Coherent polarization variation on the 5.6-day period has
at last been established in the V band, using 180 nights of data
during 1974-77; the amplitude on the semiperiod 2.8 days is 0.25
percent. Refinement of the polarization data now promises an
independent estimate of the inclination: a first analysis suggests ~ 70o
implying substantially lower masses than previously thought."
OCCULTATIONS BY MINOR PLANETS
D. Wallentinsen, Albuquerque, New Mexico, provides preliminary
predictions for occultations of SAO 159250 (mv = 8.8) by (16) Psyche
(mv = 11.7) on 1978 Feb. 25d15h.1 UT and of SAO 206553 (8.1) by
(704) Interamnia (10.8) on Apr. 28d08h.9. The nominal occultation
track of the (16) event is south of Australia and New Zealand and
across the southern Pacific Ocean; that of the (704) event is
across northwestern Brazil, Colombia, Ecuador, into the central
Pacific Ocean. Maximum durations will be 0.5 min in each case.
PERIODIC COMET KOPFF (1976b)
The following precise positions have been reported:
1977 UT R. A. (1950) Decl. m2 Observer
June 12.73588 0 37 01.85 + 0 57 46.4 15.0 Gilmore
12.76395 0 37 04.80 + 0 57 59.5 "
23.31117 0 54 41.87 + 2 19 42.4 McCrosky
Aug. 19.29469 1 46 20.79 + 4 30 08.1 Shao
Sept.11.33013 1 40 26.65 + 2 48 41.7 McCrosky
Oct. 12.70694 1 14 02.14 - 0 21 11.4 Jekabsons
A. C. Gilmore (Mount John University Observatory). 61-cm f/12.7
Cassegrain reflector. Measurer: P. M. Kilmartin.
R. E. McCrosky and C.-Y. Shao (Harvard College Observatory, Agassiz
Station). 155-cm reflector. Measurers: Shao and J. H. Bulger.
The June 23 position replaces that on IAUC 3117.
P. Jekabsons (Perth Observatory, Bickley). 33-cm astrograph.
1977 December 8 (3149) Brian G. Marsden
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