Central Bureau for Astronomical Telegrams
IAUC 2761: Obs OF COMETS; 1975d; TRANSIENT X-RAY SOURCE; NOVAE
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Read IAUC 2762
Circular No. 2761
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
OBSERVATIONS OF COMETS
Dr. Elizabeth Roemer, University of Arizona, provides the
following precise positions of comets P/Honda-Mrkos-Pajdusakova
(1974f), van den Bergh (1974g), P/Boethin (1975a), P/West-Kohoutek-Ikemura
(1975b) and P/Kohoutek (1975c). Unless otherwise specified
in a Note, the observations were obtained using the Steward Observatory's
229-cm reflector on Kitt Peak, and L. M. Vaughn assisted.
All the plates were measured by Carolyn C. McCarthy.
Comet 1974/75 UT R. A. (1950) Decl. m2 Note
1974f Nov. 10.07292 18 33 20.23 -12 45 25.8 1
10.09682 18 33 23.25 -12 45 31.1
1974g Jan. 6.07986 1 29 00.64 +23 16 36.4 2
6.10594 1 29 01.00 +23 16 26.2 2
Feb. 5.09722 1 40 12.09 +20 44 23.7
5.12488 1 40 12.91 +20 44 17.4
1975a Mar. 7.15532 3 23 22.81 +24 20 28.0 ~18.3 3
7.16574 3 23 25.48 +24 20 38.1 3
14.17431 3 52 41.70 +25 59 26.8 ~18.5 4
14.19792 3 52 47.53 +25 59 42.9 4
1975b Mar. 7.13617 3 05 26.60 +19 49 47.2 ~17.5 5
7.14254 3 05 27.61 +19 49 59.3 5
1975c Mar. 7.18964 4 54 11.20 +20 24 59.5 ~18.5 6
7.19792 4 54 12.52 +20 24 59.6 6
Notes. (1) comet on top of a star trail in poor seeing; (2) not a
very good reference star configuration; R. A. McCallister
assisted; (3) comet poorly condensed visually; a very small image
photographically, not quite as centrally condensed as comet
1975c; (4) observations made using the 154-cm reflector at the
Lunar and Planetary Laboratory1s Catalina Station; no observing
assistant; the comet was a very small spot, possibly embedded in
a very faint coma as large as 1' in diameter; (5) visually an
asymmetric coma, extending 1' to 2', mostly to the east; photographically
a condensation at the apex of an asymmetric coma to
the east; (6) photographically a condensation embedded in a coma
about 1' in diameter; condensation not symmetric, bisected center
of gravity; one end of star trails somewhat fuzzy.
COMET BRADFIELD (1975d)
Dr. B. E. Westerlund, European Southern Observatory, communicates
the following account of spectroscopic observations by J.-P.
Swings: "Two plates (dispersion 40 A/mm, exposures 6 and 12 min)
covering the spectral region 3600-5200 A were obtained on Mar. 16.0
and 17.0 UT using an image-tube spectrograph attached to the Cassegrain
focus of the 100-cm telescope. Both exposures, although
rather weak, exhibit a medium-strength continuum corresponding to
the central condensation of the head. In addition, the following
emission bands were detected: CN (0,0) 3883.4 A (P branch, R branch
to about R13); CN (0,1) 4216.0 A (P and R branches well separated);
C3 emissions at 4051.6, 4039.6, 4074.4, 4100-4137 A; C2 (2,1)
4715 A; C2 (3,2) 4698 A; C2 (4,3) 4685 A; C2 (5,4) 4679 A; C2 (6,5)
4670 A; C2 (0,0) 5165 A; C2 (1,1) 5129 A. The spectrum is very similar
to that of comet 1941 I, reproduced on Plate I, No. 2 in the
Atlas of Representative Cometary Spectra by P. Swings and L. Haser,
except that CH (0,0) 4315 A is absent in the case of comet 1975d."
TRANSIENT X-RAY SOURCE
W. A. Wheaton, W. A. Baity and L. E. Peterson, University of
California at San Diego, write: "The UCSD OSO-7 cosmic x-ray experiment
shows that a transient x-ray source appeared in the Cen
XR-2 region between Dec. 1971 and Apr. 1972. The source appears
also in data from June 1972. A preliminary position believed good
to +/- 3o is R.A. = 14h12m, Decl. = -62o (equinox 1972.0). The mean
intensity at 10 keV was approximately 4 x 10**-3 ph cm**-2 s**-1 keV**-1 in the
1972 Apr. 22-25 data, when the spectrum appeared similar to a 35
keV thermal bremsstrahlung form. The emission was evident beyond
50 keV by June 1972."
NOVAE
Further selected visual magnitude estimates (cf. IAUC 2750):
GK Per. Feb. 20.90 UT, 10.9 (U. Hopp, Wilhelm Foerster
Observatory); 22.78, 12.0 (Hopp); 25.80, 12.2 (Hopp); 28.0, 11.8 (E.
Mayer, Barberton, Ohio); 28, 12.1 (G. Comello, Kapteyn Astronomical
Laboratory); Mar. 3.81, 12.5 (Hopp); 6.1, 12.6 (J. Bortle, Brooks
Observatory); 7.1, 12.5 (Bortle); 9.1, 12.9 (Mayer).
Nova Per 1974. Feb. 8.78, 12.1 (U. Surawski, Wilhelm Foerster
Observatory); 15.92, 12.8 (Surawski); 22.81, 13.1: (Surawski);
26.94, 13.2 (Surawski); Mar. 3.82, 13.5 (Surawski); 8.0, 12.2 (P.
Taylor, Boynton Beach, Florida).
1975 March 25 (2761) Brian G. Marsden
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