Circular No. 7653

Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION

Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.

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COMET C/2001 A2 (LINEAR) D. Schleicher, Lowell Observatory; and R. Greer, Wittenberg Univer-

sity, write: “We obtained six sets of narrowband photometry of comet C/2001 A2 on June 27 and 28, using the Hall 1.1-m telescope at Lowell Observatory, with the following averaged results: log Q(OH) = 28.68; log Q(CN) = 26.09; log Afρ = 2.46 (445 nm; cf. IAUC 7342). The equivalent log Q(water; vectorial) is 28.81. No significant temporal or aperture variations were observed.”

Ephemeris extension to IAUC 7638 (elements MPEC 2001-M48):

2001 TT α_{2000} δ_{2000} Δ r ϵ β m_{1}
June 30 0^{h}52.^{m}11 − 6^{o}41.^{′}9 0.244 1.041 89.^{o}0 77.^{o}5  4.1
July 2 0 28.82 − 3 07.7 0.245 1.065 94.8 72.0 4.2
4 0 06.03 + 0 23.4 0.249 1.090 100.5 66.5  4.4
6 23 44.06 + 3 43.9 0.256 1.115 106.1 61.2  4.5
8 23 23.16 + 6 48.1 0.266 1.141 111.3 56.1  4.7
10 23 03.51 + 9 32.5 0.279 1.166 116.1 51.5  4.9
12 22 45.22 +11 55.6 0.294 1.192 120.4 47.3  5.1
14 22 28.32 +13 57.7 0.311 1.219 124.2 43.6  5.3
16 22 12.82 +15 40.0 0.330 1.245 127.6 40.3  5.5
18 21 58.65 +17 04.3 0.351 1.272 130.5 37.4  5.8
20 21 45.75 +18 12.8 0.373 1.299 132.9 34.9  6.0
22 21 34.05 +19 07.5 0.396 1.326 135.0 32.8  6.2
24 21 23.45 +19 50.5 0.421 1.353 136.7 31.0  6.4
26 21 13.87 +20 23.3 0.446 1.381 138.1 29.4  6.6
28 21 05.22 +20 47.7 0.473 1.408 139.2 28.1  6.9
30 20 57.42 +21 05.0 0.500 1.435 140.1 27.0  7.1
Aug. 9 20 28.75 +21 18.1 0.650 1.573 141.1 23.9  8.0
19 20 12.47 +20 24.9 0.815 1.710 138.5 23.1  8.9
29 20 04.33 +19 06.9 0.996 1.847 134.1 23.1  9.7
Sept. 8 20 01.72 +17 44.2 1.189 1.982 128.8 23.3 10.3
18 20 02.97 +16 26.0 1.395 2.116 122.9 23.5 11.0
28 20 07.04 +15 17.2 1.611 2.248 116.8 23.5 11.6

Visual m_{1} estimates: June 21.11 UT, 4.1 (N. Biver, Chisamba, Zambia, naked eye); 22.36, 4.1 (A. Amorim, Florianopolis, Brazil, naked eye); 24.75, 3.8 (D. A. J. Seargent, The Entrance, N.S.W., naked eye); 26.73, 4.4 (P. Kemp, Auckland, New Zealand, 8×50 binoculars); 27.47, 4.2 (C. S. Morris, Fillmore, CA, 10×50 binoculars); 28.36, 4.6 (Amorim); 29.38, 4.2 (L. A. Mansilla, Canopus de Rosario, Argentina, 7×50 binoculars).

2001 June 29  \begin{matrix}c \\ ◯ \end{matrix} Copyright 2001 CBAT  Daniel W. E. Green