Central Bureau for Astronomical Telegrams
IAUC 2917: 1976a; 1975n
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Circular No. 2917
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
COMET BRADFIELD (1976a)
M. P. Candy, Perth Observatory, provides the following parabolic
elements and ephemeris; the orbit is based on three accurate
observations over a 2-day arc, and residuals are less than 1".
T = 1976 Feb. 24.837 ET Peri. = 313.11
Node = 159.93 1950.0
q = 0.8488 AU Incl. = 47.00
1976 ET R. A. (1950) Decl. Delta r m1
Feb. 26 2 23.9 -28 48 0.677 0.849 8.9
28 2 33.5 -27 01
Mar. 1 2 43.6 -25 00
3 2 54.1 -22 42
5 3 05.0 -20 07 0.553 0.866 8.6
Magnitudes have been added, calculated from m1 = 10.5 + 5 log Delta +
10 log r.
COMET WEST (1975n)
E. P. Ney and J. Stoddart, O'Brien Observatory, University of
Minnesota, report the following visual and infrared magnitudes,
obtained on Feb. 23.8 UT with a diaphragm of 20": V = +0.6, R = +0.3,
I = -0.4; 1.2 um, -1.0; 1.6 um, -1.7; 2.2 um, -3.2; 3.5 um, -5.3; 4.8 um,
-6.3; 8.5 um, -7.8; 10.6 um, -8.5; 12.5 um, -8.3; 18 um, -8.7. They
add: "The tail has a width of 4' at a distance of 7' east of the
nucleus and a surface brightness 0.014 that of the coma in the 20"
beam. The albedo is 0.23 and the integrated total visual magnitude
-1.0 +/- 0.3. There is no evidence of an antitail or of material on
the sunward side. This comet is now intrinsically 1.4 magnitudes
brighter than 1973 XII (Kohoutek) at comparable r and Delta."
Further total visual magnitude estimates: Feb. 16.43 UT, 4
(T. B. Tregaskis, Mount Eliza, Victoria, 10 x 50 binoculars; 30'
tail); 17.4, 3.0 (M. Ashley, Canberra, A.C.T., 20-cm reflector);
20.41, 1 (C. L. Curnick, Box Hill, Victoria, 10 x 50 binoculars; 40'
tail); 21.34, < 1 (R. R. D. Austin, Mount John University Observatory,
7 x 50 binoculars; tail 1o in p.a. 90o); 23.95, -1.6 (J.
Bortle, Brooks Observatory, 10 x 50 binoculars; tail 20'-30' in p.a.
100o); 24.95, -1.9 (Bortle); 25.73, -2 (P. Collins and S. O'Meara,
Harvard Observatory, 6-cm and 23-cm refractors; in broad daylight).
1976 February 26 (2917) Brian G. Marsden
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