Electronic Telegram No. 5239 Central Bureau for Astronomical Telegrams Mailing address: Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network COMET C/1971 M1 (EDWARDS) A comet found belatedly by Leonard R. Edwards (then a sergeant assigned to the U.S. Air Force base near Timaru, New Zealand) on three 45-s film exposures taken on 1971 June 19 UT with a Baker-Nunn camera at the Timaru base, and reported a year later (cf. IAUC 2432) without a designation or name due to lack of confirmation, has been found on additional photographs on six nights in 1971 for over a month, following a dedicated search by M. Meyer and G. W. Kronk (as part of their research for a forthcoming book on uncomfirmed comets), permitting now the computation of an orbit and assignment of designation and name. Two of the positions come from slightly trailed plates taken by J. A. Bruwer and M. Klerk with the 25-cm Franklin-Adams Star Camera located at the Leiden Southern Station of Union/Republic Observatory at Hartbeespoort, South Africa, in which the comet was near the edge of the plates but showed a short tail. The other observations come from plates taken with a 4.2-cm Damon South Patrol camera located at the Bloemfontein station of Boyden Observatory (and run by the Harvard and Smithsonian Observatories). On the July 25 plates, the comet shows a 5'-long tail in p.a. 150 degrees despite the poor scale; in some cases, only the beginning and end of trails could be measured. The available new astrometry for the comet from Meyer and Kronk, along with the precessed discovery position of Edwards, are tabulated below. A search for the comet in other plate archives from 1971 and 1972 has produced no results. 1971 UT R.A. (2000) Decl. Mag. Observer June 19.58551 17 49 42.87 -23 11 17.6 10 Edwards 20.80972 17 47 18.34 -22 48 37.5 10 Bruwer 20.85972 17 47 12.47 -22 47 34.5 " 20.89028 17 47 09.16 -22 46 52.8 (Damon) 20.97361 17 46 59.64 -22 45 34.3 " 22.88472 17 43 17.05 -22 09 22.9 " 23.88194 17 41 20.72 -21 50 19.2 " July 18.76806 16 58 35 -13 49 44 " 21.71806 16 54 32.49 -12 56 09.3 " 21.80139 16 54 26.87 -12 54 57.6 " 25.72708 16 49 30.67 -11 46 07.2 11 " 25.81042 16 49 25.05 -11 44 59.0 " The following parabolic orbital elements by S. Nakano (Central Bureau) are from 9 observations spanning 1971 June 20-July 25 (mean residual 4".3). The comet passed 2.62 AU from Jupiter on 1971 July 12 UT. T = 1971 Dec. 7.3736 TT Peri. = 43.9708 Node = 267.7765 2000.0 q = 2.885915 AU Incl. = 97.1850 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 4.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 1971 03 30 19 15.12 -37 27.7 3.784 3.810 83.9 15.1 11.5 1971 04 19 19 11.68 -35 22.7 3.324 3.689 103.4 15.4 11.1 1971 05 09 18 57.01 -32 44.8 2.893 3.574 125.4 13.3 10.7 1971 05 29 18 29.67 -29 00.1 2.546 3.464 150.4 8.3 10.3 1971 06 18 17 52.78 -23 40.4 2.345 3.360 178.2 0.6 10.1 1971 07 08 17 15.41 -17 14.7 2.325 3.265 153.1 8.1 9.9 1971 07 28 16 46.89 -11 08.2 2.470 3.177 126.2 14.9 10.0 1971 08 17 16 30.74 -06 19.2 2.716 3.100 102.6 18.6 10.1 1971 09 06 16 25.73 -02 47.1 2.998 3.033 82.3 19.2 10.2 1971 09 26 16 29.26 -00 04.8 3.261 2.977 64.9 17.8 10.4 1971 10 16 16 39.01 +02 17.5 3.472 2.934 50.1 15.1 10.4 1971 11 05 16 53.25 +04 44.7 3.610 2.904 38.8 12.4 10.5 1971 11 25 17 10.67 +07 38.6 3.666 2.889 33.0 10.7 10.5 1971 12 15 17 30.27 +11 19.1 3.643 2.887 34.6 11.2 10.5 1972 01 04 17 51.19 +16 05.3 3.553 2.899 42.1 13.1 10.5 1972 01 24 18 12.60 +22 14.6 3.420 2.926 52.4 15.5 10.4 1972 02 13 18 33.58 +29 59.5 3.275 2.966 63.3 17.3 10.4 1972 03 04 18 52.98 +39 19.5 3.155 3.018 73.0 18.3 10.3 1972 03 24 19 08.97 +49 51.2 3.095 3.083 80.0 18.6 10.4 1972 04 13 19 17.96 +60 45.7 3.116 3.158 83.1 18.4 10.5 1972 05 03 19 10.72 +70 58.6 3.221 3.243 82.3 17.9 10.6 1972 05 23 18 16.97 +79 13.5 3.390 3.337 78.4 17.3 10.8 1972 06 12 15 27.26 +82 50.5 3.593 3.438 73.1 16.4 11.1 1972 07 02 13 02.22 +80 18.7 3.800 3.547 68.0 15.4 11.3 1972 07 22 12 22.14 +76 23.4 3.986 3.661 64.3 14.5 11.5 1972 08 11 12 18.73 +73 09.0 4.131 3.781 63.0 13.8 11.7 1972 08 31 12 28.78 +70 58.9 4.227 3.904 64.8 13.5 11.9 1972 09 20 12 45.12 +70 00.4 4.271 4.032 69.6 13.5 12.0 1972 10 10 13 05.04 +70 19.4 4.271 4.163 77.1 13.5 12.1 1972 10 30 13 27.38 +72 01.1 4.244 4.296 86.3 13.3 12.2 1972 11 19 13 51.69 +75 07.5 4.215 4.431 96.2 12.8 12.3 1972 12 09 14 18.10 +79 32.3 4.215 4.569 104.9 12.0 12.4 1972 12 29 14 49.22 +84 57.0 4.275 4.708 110.3 11.3 12.5 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 March 27 (CBET 5239) Daniel W. E. Green