Electronic Telegram No. 5325 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 P/2023 W1 = P/2001 Q6 (NEAT) Hidetaka Sato (Bunkyo-ku, Tokyo, Japan) reports his recovery of comet P/2001 Q6 (cf. IAUCs 7698, 7722, 7734, 7753) on images obtained with telescopes at the "Deep Sky Chile" observatory at Rio Hurtado (astrometry tabulated below). Eight stacked 120-s CMOS exposures obtained with a 0.18-m f/2.8 astrograph on Nov. 29.0 UT show a strongly condensed object with an outer coma 35" in diameter and no tail; the magnitude was measured within a circular aperture of radius 18".5. Twelve stacked 30-s follow-up CCD exposures taken on Nov. 30.04-30.08 with a 0.51-m f/6.8 astrograph show a strongly condensed coma 17" in diameter with no tail; the magnitude was measured within a circular aperture of radius 8".6. Sixteen stacked 30-s exposures taken with the 0.51-m astrograph on Dec. 1.1 show a moderately condensed coma 17" in diameter and no tail; the magnitude was measured within a circular aperture of radius 8".6. On Dec. 3.1, sixteen stacked 30-s exposures showed a moderately condensed coma 17" in diameter with no tail; the magnitude was 18.0 as measured within a circular aperture of radius 8".6. 2023 UT R.A. (2000) Decl. Mag. Observer Nov. 29.02810 23 09 18.94 -24 07 59.8 Sato 29.03466 23 09 18.71 -24 07 45.1 17.6 " 30.04047 23 08 50.77 -23 29 28.0 " 30.04261 23 08 50.71 -23 29 23.0 " 30.07806 23 08 49.76 -23 28 02.3 18.3 " Dec. 1.08836 23 08 24.60 -22 49 35.1 " 1.09271 23 08 24.52 -22 49 24.9 18.0 " Nine additional stacked 60-s exposures taken remotely by Hidetaka Sato with a 0.51-m f/6.8 astrograph at Siding Spring, NSW, Australia, on Dec. 5.44-5.45 UT show a strongly condensed object with an outer coma 1'.0 in diameter and no tail; the magnitude was 17.5 as measured within a circular aperture of radius 29".5. A delay by the Minor Planet Center in announcing the recovery led to the comet being inadvertently posted as a supposedly new comet on the MPC's PCCP website after the comet was found by D. Rankin (Mt. Lemmon 1.5-m reflector) on Dec. 9.1 UT at mag 18.5 (coma diameter 10".5). Hirohisa Sato has measured twenty-five stacked 60-s CCD exposures taken by T. Ikemura with a 0.38-m f/4.2 reflector at Shinshiro, Japan, on Dec. 10.44-10.46 that show a condensed coma about 7" in diameter (total mag 18.3) with no tail. The available astrometry appears on MPEC 2023-X258. The residuals of Sato's recovery observations are -0.02 deg in R.A. and +1.22 deg in Decl. from the prediction in NK 869 (and the ICQ's 2023 Comet Handbook), with a corresponding correction of Delta(T) = -2.7 days. The following linked orbital elements by S. Nakano (Central Bureau) are from 393 observations spanning 2001-2023 (mean residual 0".6). The comet passed 0.72 AU from Jupiter on 1957 Nov. 3 UT. Epoch = 2001 Nov. 27.0 TT T = 2001 Nov. 9.46803 TT Peri. = 43.33085 e = 0.8238140 Node = 22.13540 2000.0 q = 1.4081706 AU Incl. = 56.85456 a = 7.9925205 AU n = 0.04361927 P = 22.60 years Epoch = 2024 Feb. 20.0 TT T = 2024 Feb. 26.24346 TT Peri. = 42.91763 e = 0.8236492 Node = 22.18500 2000.0 q = 1.4057875 AU Incl. = 56.90844 a = 7.9715387 AU n = 0.04379160 P = 22.51 years Epoch = 2046 Aug. 3.0 TT T = 2046 July 22.93079 TT Peri. = 42.68258 e = 0.8234539 Node = 22.10244 2000.0 q = 1.4125491 AU Incl. = 56.83395 a = 8.0010218 AU n = 0.04354977 P = 22.63 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 12.0 and 2.5n = 20 for the magnitudes (which is some 3 mag fainter than at its 2001 apparition). Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2023 10 23 00 07.05 -44 44.3 1.435 2.112 119.7 24.2 19.3 2023 11 02 23 42.98 -40 11.6 1.417 2.028 113.5 26.7 18.9 2023 11 12 23 25.29 -34 39.8 1.422 1.945 106.1 29.3 18.5 2023 11 22 23 13.95 -28 33.9 1.448 1.865 98.1 31.6 18.2 2023 12 02 23 08.07 -22 15.0 1.490 1.788 90.1 33.5 17.9 2023 12 12 23 06.59 -15 56.1 1.542 1.715 82.3 34.7 17.6 2023 12 22 23 08.61 -09 44.0 1.601 1.646 74.9 35.2 17.4 2024 01 01 23 13.37 -03 40.7 1.661 1.585 68.1 35.2 17.1 2024 01 11 23 20.38 +02 14.6 1.720 1.530 62.0 34.6 16.9 2024 01 21 23 29.32 +08 04.2 1.775 1.484 56.7 33.7 16.7 2024 01 31 23 40.01 +13 50.6 1.822 1.447 52.3 32.6 16.5 2024 02 10 23 52.46 +19 36.5 1.862 1.422 48.8 31.5 16.4 2024 02 20 00 06.86 +25 24.2 1.894 1.408 46.4 30.6 16.4 2024 03 01 00 23.56 +31 14.6 1.919 1.407 45.0 29.9 16.4 2024 03 11 00 43.23 +37 07.8 1.939 1.417 44.7 29.5 16.5 2024 03 21 01 06.86 +43 01.5 1.956 1.440 45.2 29.4 16.6 2024 03 31 01 35.97 +48 49.2 1.974 1.474 46.3 29.4 16.8 2024 04 10 02 12.81 +54 19.5 1.996 1.517 47.8 29.3 17.1 2024 04 20 03 00.25 +59 12.4 2.026 1.570 49.4 29.1 17.5 2024 04 30 04 00.79 +62 58.0 2.068 1.630 50.8 28.6 17.8 2024 05 10 05 13.35 +65 01.4 2.124 1.697 51.8 27.9 18.2 2024 05 20 06 29.87 +65 00.5 2.196 1.769 52.3 26.9 18.7 2024 05 30 07 39.27 +63 05.7 2.283 1.845 52.2 25.7 19.1 2024 06 09 08 35.94 +59 52.2 2.386 1.924 51.4 24.4 19.6 2024 06 19 09 20.49 +55 57.0 2.502 2.007 50.0 22.8 20.0 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 December 13 (CBET 5325) Daniel W. E. Green