Central Bureau for Astronomical Telegrams
IAUC 2863: A0535+26; Cyg X-1; Obs OF COMETS; JUPITER XIII (LEDA); COORDINATES OF OBSERVATORIES
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Read IAUC 2864
Circular No. 2863
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
Western Union: RAPID SATELLITE CAMBMASS
A0535+26
P. C. Joss, Massachusetts Institute of Technology, reports
that the SAS-3 Group has detected a new turn-on of the transient,
pulsing, x-ray source in Taurus, A0535+26 (IAUC 2774, 2780, 2784,
2787, 2790; see also Rosenberg et al. 1975, Nature 256, 628). The
source was undetected (with an upper limit of ~ 0.1 times the 1-10
keV flux of the Crab Nebula) on Nov. 5.5 UT but attained a 1-10 keV
flux of ~ 0.2 times that of the Crab by Nov. 7.5 UT. The source is
observed to pulse with the 104-s periodicity previously reported.
He suggests that the optical candidate for the source, HDE 245770,
be monitored for unusual spectral or photometric behavior. Immediate
searches for other optical candidates in the x-ray error box (R.A. =
5h35m47s +/- 2s, Decl. = +26o16'52" +/- 45", equinox 1950.0) would also
be valuable. The observation of another x-ray turn-on about six
months after the original detection probably excludes models
involving highly eccentric orbits with periods in excess of ~ 1 year.
CYGNUS X-1
L. J. Kaluzienski, S. S. Holt, E. A. Boldt and P. J.
Serlemitsos, Goddard Space Flight Center, report the detection of
another Cyg X-1 x-ray increase, measured with the Ariel 5 all-sky
monitor. The Cyg X-1 intensity slowly increased during the past
few weeks by a total of approximately 25 percent, increased briefly
by an additional factor of two on Nov. 2, and increased again on
Nov. 4-5. This relatively high intensity is slightly more than
half the maximum intensity during the flare in May (IAUC 2778,
2779) but twice the post-flare intensity.
J. Grindlay and E. Schreier, Center for Astrophysics, Harvard
and Smithsonian Observatories; and A. den Boggende and A. Brinkman,
Laboratory for Space Research, Utrecht, report that this sudden
increase in the x-ray flux of Cyg X-1 was independently detected by
ANS. Between Nov. 2.0 and 4.0 UT the 1-7 keV flux was observed to
be fluctuating between 20 and 30 ANS cts/s (approximately 300-450
Uhuru units). Starting on Nov. 4.5 UT the source activity increased,
reaching a first peak (1000 Uhuru units) on Nov. 5.2, followed
by a sharp decrease on Nov. 5.4 (650 Uhuru units) and a second
peak (1200-1500 Uhuru units) on Nov. 6.1. By Nov. 7.2 the
source had decreased to the Nov. 3 level. The total increase (Nov.
2-6) was a factor of three at 2 keV, while above 8 keV there was no
significant change. This event may be similar to the short-term
increase of Sept. 6 (IAUC 2833) or the longer-duration event of May
(IAUC 2778, 2779). Further observations at radio, optical and
x-ray wavelenqths are needed.
OBSERVATIONS OF COMETS
The following precise positions of periodic comets
Schwassmann-Wachmann 1, Gunn, Schwassmann-Wachmann 2 (1973l),
West-Kohoutek-Ikemura (1975b) and Wolf (1975f) have been obtained by R. E.
McCrosky, C. Y. Shao, G. Schwartz and J. H. Bulger with the 155-cm
reflector at Harvard Observatory's Agassiz Station:
Comet UT R. A. (1950) Decl.
P/S-W 1 1975 Sept. 4.18824 1 23 22.85 +19 01 11.0
P/Gunn 1974 Dec. 23.36830 12 39 02.05 + 7 05 28.5
1975 July 3.11194 12 27 00.80 + 4 58 42.9
1973l 1975 June 11.09775 12 26 03.28 + 1 56 13.9
1975b 1975 May 30.13709 7 52 02.05 +40 32 30.2
1975f 1975 June 11.26970 21 12 25.97 +18 21 24.4
JUPITER XIII (LEDA)
E. Roemer, Lunar and Planetary Laboratory, provides the
following precise positions, derived from plates taken with the 154-cm
reflector at the Catalina Station. Measurer: C. C. McCarthy.
1975 UT R. A. (1950) Decl.
Oct. 5.28333 1 21 05.50 + 6 39 47.3
5.35069 1 21 03.76 + 6 39 33.1
COORDINATES OF OBSERVATORIES
The following summary of coordinates of observatories supplements
the lists on IAUC 2417 and 2645:
-Long. 10**7 Dxy 10**7 DZ
Berne Astron. Inst. Zimmerwald Sta. 0h29m9 = 7o47 -292 -310
Cracow Obs. Fort Skala Station 1 19.3 = 19.83 -274 -325
Turku Astron. Inst. Kevola Station 1 31.0 = 22.75 -211 -369
JCPM Oi Station 9 09.4 = 137.36 -349 -244
JCPM Ayashi Station 9 23.1 = 140.78 -335 -263
JCPM Kimachi Station 9 23.5 = 140.86 -335 -263
JCPM Sapporo Station 9 25.5 = 141.38 -312 -290
Kambah, near Canberra (Herald) 9 56.2 = 149.06 -348 +246
University of Victoria 15 46.7 = 236.68 -283 -318
1975 November 10 (2863) Brian G. Marsden
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