Central Bureau for Astronomical Telegrams
IAUC 2937: 1975n
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Read IAUC 2938
Circular No. 2937
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 WEST (1975n)
The following precise positions have been reported:
1976 UT R. A. (1950) Decl. m1 Observer
Mar. 10.20030 21 28 04.77 + 8 38 06.4 Codina
10.21002 21 28 03.41 + 8 38 31.5 "
10.85521 21 25 55.12 + 8 53 13.8 1.5 Seki
11.21634 21 24 45.23 + 9 01 19.2 Mundet
12.84583 21 20 01.9 + 9 34 11 1.5 Seki
13.21844 21 19 02.44 + 9 41 05.9 Mundet
15.20373 21 14 14.64 +10 15 14.2 Codina
15.21397 21 14 13.23 +10 15 24.2 "
18.15405 21 08 17.61 +10 58 53.8 Milet
18.15624 21 08 17.32 +10 58 55.7 "
19.19042 21 06 28.37 +11 12 43.4 Torras
19.20847 21 06 26.16 +11 12 59.7 "
20.1611 21 04 50.93 +11 25 13.1 Surawski
22.51892 21 01 14.37 +11 53 53.6 Giclas
22.52309 21 01 14.12 +11 53 54.3 "
23.15993 21 00 20.20 +12 01 13.0 Milet
23.17410 21 00 18.95 +12 01 21.4 "
25.15281 20 57 38.87 +12 23 23.1 "
25.15443 20 57 38.66 +12 23 23.8 "
30.51811 20 51 05.34 +13 18 51.2 Giclas
J. M. Codina, J. M. Mundet and N. Torras (Fabra Observatory, Barcelona).
Evidently nucleus A and/or D.
T. Seki (Kochi Observatory, Geisei Station). Nucleus A and/or D.
From Orient. Astron. Assoc. Comet Bull. No. 124.
B. Milet (Nice Observatory). Nucleus A and/or D on Mar. 18 and 23,
apparently just nucleus A on Mar. 25.
U. Surawski and U. Hopp (Wilhelm Foerster Observatory, Berlin).
Probably nucleus A. Communicated by A. Kunert.
H. L. Giclas (Lowell Observatory). Measurer: M. L. Kantz. Nucleus
B on Mar. 22, nucleus D on Mar. 30.
Further photographic observations of the separations and position
angles of the additional nuclei (relative to nucleus A):
Nucleus B. Mar. 25.50 UT, 17".0, 319o (S. Murrell and C. Knuckles,
New Mexico State University; measured by E. J. Reese); 28.44,
19", 316o (D. A. Ketelsen, University of Iowa); 28.52, 19".6, 315o
(Murrell et al.); 31.48, 21".1, 315o (Murrell et al.); Apr. 1.48,
21".8, 314o (Murrell et al.); 2.45, 22".1, 314o (Ketelsen); 2.52,
22".2, 314o (Murrell et al.); 5.42, 25".9, 314o (Ketelsen).
Nucleus C. Mar. 25.50 UT, 17".2, 292o (Murrell et al.).
Nucleus D. Mar. 25.50 UT, 7".9, 333o (Murrell et al.); 28.44, 8".7,
326o (Ketelsen); 28.52, 8".8, 333o (Murrell et al.); 31.48, 9".4,
332o (Murrell et al.); Apr 1.48, 9".9, 329o (Murrell et al.);
2.45, 10".0, 324o (Ketelsen); 2.52, 10".2, 326o (Murrell et al.);
5.42, 11".9, 3250 (Ketelsen).
J. Bortle, Brooks Observatory, reports that although nucleus B was
some 2.5 magnitudes fainter (visually) than nucleus A on Mar. 25.4
UT and completely invisible on Mar. 26.4, it was 0.8 magnitude
brighter than nucleus A on Mar. 29.4; B was 1 magnitude fainter
than A on Mar. 31.4, and 2.0-2.5 magnitudes fainter on Apr. 5.4 and
6.4. Observations by C. Sherrod, North Little Rock, Arkansas; and
by P. Maley, Houston, Texas, on Mar. 27.4 showed B some 1.5-2.0
magnitudes fainter than A, and the above-mentioned photographic
observations indicated that the two nuclei were about equally bright
on Mar. 28.4. The last observation of nucleus C, more than 5 magnitudes
fainter than A, was by Sherrod on Mar. 27.4. Nucleus D seems
generally to have brightened, from 2.0-2.5 magnitudes fainter than
nucleus A on Mar. 25-26 to 1 magnitude fainter than A on Apr. 5-6
(Bortle). Bortle also mentioned a possible additional nucleus on
Mar. 26, perhaps 0.5 magnitude fainter than nucleus D and roughly
midway in position between nucleus A and nucleus D.
S. D. Sinvhal, Uttar Pradesh State Observatory, reports that
further observations by G. Babu (cf. IAUC 2924) showed that emission
due to CN 4210 A had disappeared by Mar. 8.0 UT; CN 3590 A was
observed from Mar. 13.0 onward but had almost disappeared by Mar.
21.0. C2 4380 A appeared on Mar. 14.0 and was quite weak by Mar.
21.0. C2 4740, 5160 ard 5630 A, CN 3880 A and Na were still strong
on Mar. 21 and C3 4050 A still noticeable.
P. Bowers, University of Maryland, reports that observations
with the 91-m telescope at the National Radio Astronomy Observatory
during Mar. 25-28 showed the average flux density of the OH emission
to be 0.27 Jy at 1667 MHz and 0.19 Jy at 1665 MHz. The 1612-MHz
line was not detected (upper limit 0.3 Jy at 3-sigma level).
Selected recent total visual magnitude estimates and tail
information: Mar. 24.53 UT, 4.0, > 15o (M. J. Mayo and J. Truxton,
Agoura, California, 10 x 50 binoculars); 25.39, 4.2, 6o in p.a.
280o-315o (Bortle, 10 x 50 binoculars); 26.38, 4.2, 4o.5 in 280o-310o
(Bortle); 27.46, 4.5, 3o.5 in 280o (Maley, 7 x 35 binoculars);
28.37, 4.3, 5o.5 in 278o-318o (Bortle); 29.39, 4.5, 6o in 278o-310o
(Bortle); 30.52, 4o.6, 12o (Mayo and Truxton); 31.38, 4.7, 4o in
277o-310o (Bortle); Apr. 1.46, 4.6, 2o (Maley); 2.35, 4.7, 2o in
270o (S. O'Meara, Harvard Observatory, naked eye); 4.39, 4.7, 2o.5
in 280o (O'Meara); 5.37, 5.4, 5o.5 in 271o-309o (Bortle); 6.37, 5.4,
5o.5 in 275o-313o (Bortle); 7.33, 5.6, 1o.5 in 280o (O'Meara).
1976 April 8 (2937) Brian G. Marsden
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