Central Bureau for Astronomical Telegrams
IAUC 3116: NEBULA NEAR CL4; Her X-1; 1977 RA; 1977k; ECLIPSES OF SATURN VIII (IAPETUS)
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Read IAUC 3117
Circular No. 3116
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
NEBULA NEAR CL4
F. J. Vrba, U.S. Naval Observatory, Flagstaff Station, reports
the recent appearance of a nebula surrounding but not centered
upon the star located 10" east of the position of the radio
source CL4 (Webster and Ryle 1976, Monthly Notices Roy. Astron. Soc.
175, 95). The nebula was discovered on four polarimetric plates
taken on Sept. 15 and was confirmed on three photometric plates
taken on Sept. 21, in both cases using the Kron electrographic
camera on the 102-cm reflector. The nebula is not seen on four
similar plates taken prior to July 15. Preliminary inspection of
the V filter plates shows the nebula to be approximately circular
with a diameter of 6" and to have significant polarization. The
nebula is not visible in the B bandpass. While no appreciable
brightness change of the star Itself has been detected during these
observations, the latest plates show the brightness of the nebula
to be nearly equal to that of the star in the V filter.
HERCULES X-1
S. H. Pravdo, R. H. Becker, J. R. Saba, P. J. Serlemitsos and
J.H. Swank, Goddard Space Flight Center, report that OSO 8 has observed
Her X-1 and the pulse period for the present epoch has been
determined. The observations spanned Aug. 31-Sept. 5, and analysis
of quick-look data yielded a heliocentric pulse period of 1s.2377967
+/- 0s.0000004. An extrapolation from the earliest reported period
(Giacconi 1975, Ann. N.Y. Acad. Sci. 262, 312) indicates a continuation
of the pulsar spin-up with P-dot/P ~ 4 x 10**-6 yr**-1. Preliminary
data from OSO 8 and the HEAO A2 experiment suggest that x-ray turn-on
occurred near binary phase 0.7 on Aug. 30 UT (assuming that turn-on
has continued to occur near phase 0.25 or 0.7).
1977 RA
Further precise positions have been reported as follows:
1977 UT R. A. (1950) Decl. Mag. Observer
Sept. 9.93368 22 54 42.92 +17 01 25.8 Wild
11.89062 22 55 54.00 +17 14 36.9 "
12.45428 22 56 15.43 +17 17 56.0 14.5 Urata
12.45868 22 56 15.49 +17 17 57.1 "
12.85972 22 56 29.62 +17 20 03.3 Wild
13.56736 22 56 55.11 +17 23 40.4 14 Seki
13.58403 22 56 55.34 +17 23 45.0 15 "
14.61007 22 57 32.82 +17 28 08.3 14.5 Urata
14.61528 22 57 33.10 +17 28 08.9 "
15.92500 22 58 22.75 +17 32 36.8 Wild
16.48542 22 58 44.68 +17 34 14.8 14.5 Urata
16.49340 22 58 44.98 +17 34 17.2 "
17.46285 22 59 22.54 +17 36 29.9 14.5 "
17.47049 22 59 22.76 +17 36 31.2 "
19.64236 23 00 47.24 +17 39 52.3 Candy
P. Wild (Astronomical Institute, Berne). The time of the discovery
observation should be changed to Sept. 4.86134 UT (IAUC 3104).
T. Urata (JCPM Yakiimo Station). From Nihondaira Obs. Circ. No. 887.
T. Seki (Kochi Observatory, Geisei Station).
N. P. Candy (Perth Observatory, Bickley). 33-cm astrograph.
PERIODIC COMET AREND-RIGAUX (1977k)
The following precise positions have been measured by C.-Y.
Shao from exposures by R. E. McCrosky and G. Schwartz with the 155-cm
reflector at the Harvard College Observatory's Agassiz Station.
The Aug. 15 position is a re-reduction of that given on IAUC 3095.
1977 UT R. A. (1950) Decl.
Aug. 15.32794 2 07 18.99 -10 05 42.0
18.32859 2 10 26.09 -10 29 13.9
ECLIPSES OF SATURN VIII (IAPETUS)
J. G. Porter, British Astronomical Association, writes that
the predictions for the Oct. 19-20 eclipses of Iapetus by Saturn
and its rings (Handb. Br. Astron. Assoc. for 1977) have been revised
by E. R. Delo and himself using the theory of the motion of
Iapetus by A. T. Sinclair. Revised figures for both these and the
1978 Jan. 7-8 eclipses are given below, the latter being from Handb.
Br. Astron. Assoc. for 1978. At the stated times, the center of
the satellite is at the edge of the umbra, and the magnitude of the
eclipse is then 0.5. The figures therefore differ from those computed
on a different principle by A. W. Harris (IAUC 3074). The
separation d and position angle P are measured with respect to the
center of the apparent disk of Saturn.
Eclipse by 1977 ET d P 1978 ET d P
Ring A, begins Oct. 19d12h56m 65" 283o Jan. 8d09h29m 28" 308o
ends 19 14 07 63 283 8 10 41 26 311
Ring B, begins 19 14 57 62 284 - - -
ends 19 17 26 58 284 8 07 44 30 305
Planet, begins 19 19 45 54 285 7 19 11 52 291
ends 20 05 07 40 290 8 04 07 36 299
1977 October 6 (3116) Brian G. Marsden
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