Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 2718: SMC X-1; X-RAY SKY SURVEY; 1972 IX

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 2717 SEARCH Read IAUC 2719
IAUC number 

                                                  Circular No. 2718
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


SMC X-1
     I. R. Tuohy and C. G. Rapley, Mullard Space Science Laboratory,
University College, London, report: "An x-ray eclipse of the
binary source SMC X-1 was observed with the Copernicus 2.5 to 7.5
keV detector on Aug. 16.  The center of the transition to the low
state occurred on Aug. 16.372 +/- 0.021 and was followed by a slow
turn-on on Aug. 17.007 +/- 0.042.  The eclipse duration is in agreement
with the Uhuru value of 0.60 +/- 0.03 day.  Using this figure
and the Uhuru phase for the center of the low state (1971 Jan.
12.99 +/- 0.02 UT), we obtain an improved period of 3.89223 +/- 0.00012
days for SMC X-1.  The previous eclipse of Aug. 12-13 was not detected
due to a low source intensity."


X-RAY SKY SURVEY
     Dr. K. A. Pounds, Leicester University, informs us that the
UK-5 Sky Survey experiment will continuously monitor the galactic
plane during Nov. 10-25.  X-ray sources between b = +/- 10o will be
covered at 2-20 keV with sensitivity to 5-10 Uhuru units.


COMET SANDAGE (1972 IX)
     Continuation to the ephemeris on IAUC 2597:

     1974/75 ET  R. A. (1950) Decl.     Delta     r      m2
     Dec. 19     0 02.13    +50 30.8    6.962   7.366   20.4
          29     0 05.35    +49 07.9
     Jan.  8     0 09.55    +47 53.1    7.306   7.483   20.6
          18     0 14.59    +46 47.4
          28     0 20.30    +45 51.3    7.681   7.600   20.7
     Feb.  7     0 26.55    +45 04.7
          17     0 33.23    +44 27.5    8.052   7.717   20.9
          27     0 40.20    +43 59.0
     Mar.  9     0 47.38    +43 38.7    8.392   7.835   21.1
          19     0 54.67    +43 25.8
          29     1 01.98    +43 19.5    8.677   7.953   21.2

             m2 = 7.5 + 5 log Delta + 10 log r


1974 November 14               (2718)              Brian G. Marsden

Read IAUC 2717 SEARCH Read IAUC 2719

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!