Electronic Telegram No. 5410 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/2024 N1 (PANSTARRS) R. Weryk, Department of Physics and Astronomy, University of Western Ontario, reports the discovery of another comet in images obtained on July 1 with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala; the discovery observations and additional Pan-STARRS2 observations found by Weryk from June 6 and 15 are tabulated below. 2024 UT R.A. (2000) Decl. Mag. June 6.48568 21 40 04.35 +19 43 31.5 22.7 6.49816 21 40 04.09 +19 43 38.9 22.9 6.51064 21 40 03.83 +19 43 45.6 22.6 15.49308 21 36 31.21 +21 07 19.8 21.6 15.53063 21 36 30.17 +21 07 40.7 21.8 July 1.46141 21 27 26.52 +23 26 40.9 21.8 1.47529 21 27 25.97 +23 26 47.1 21.1 1.48916 21 27 25.40 +23 26 53.9 21.7 1.50310 21 27 24.80 +23 27 00.6 21.7 1.57305 21 27 21.92 +23 27 35.5 22.4 1.57370 21 27 21.89 +23 27 35.7 22.5 Weryk (and R. Wainscoat) obtained three 60-s gri-band follow-up images with the 3.6-m Canada-France-Hawaii Telescope on July 3.4 UT (queue observer H. Januszewski; queue coordinator V. Khatu) in 0".9 seeing that show a condensed head of size about 1".5 (full-width-at-half-maximum) with no obvious tail. Weryk adds that three additional 90-s gri-band CFHT images taken on July 4.6 in 0".8 seeing show this to be a definite comet, with a condensed head of size 1".3 (FWHM) and a broad, 8"-long tail spanning p.a. 180-215 degrees. The available astrometry appears on MPEC 2024-N107. The following parabolic orbital elements by S. Nakano (Central Bureau) are from 20 observations spanning 2024 June 6-July 5 (mean residual 0".2). The comet passed 0.48 AU from Saturn on 2022 Sept. 14 UT. T = 2025 Oct. 18.93490 TT Peri. = 91.23812 Node = 323.00307 2000.0 q = 4.3991048 AU Incl. = 88.76142 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 11.5 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2024 06 14 21 37.19 +20 53.6 5.542 5.892 105.4 9.6 21.4 2024 06 24 21 32.13 +22 23.5 5.368 5.842 113.1 9.2 21.3 2024 07 04 21 25.67 +23 47.2 5.211 5.792 120.4 8.7 21.2 2024 07 14 21 17.90 +25 02.0 5.075 5.743 126.9 8.1 21.1 2024 07 24 21 08.98 +26 05.1 4.963 5.694 132.1 7.6 21.0 2024 08 03 20 59.22 +26 54.5 4.877 5.646 135.6 7.2 21.0 2024 08 13 20 49.00 +27 28.3 4.818 5.598 136.6 7.1 20.9 2024 08 23 20 38.79 +27 46.3 4.788 5.551 135.2 7.4 20.9 2024 09 02 20 29.05 +27 49.5 4.784 5.504 131.4 7.9 20.8 2024 09 12 20 20.22 +27 39.8 4.804 5.458 126.0 8.6 20.8 2024 09 22 20 12.63 +27 20.4 4.846 5.412 119.6 9.3 20.8 2024 10 02 20 06.51 +26 54.9 4.905 5.367 112.4 9.9 20.8 2024 10 12 20 01.98 +26 26.7 4.977 5.323 105.0 10.4 20.8 2024 10 22 19 59.05 +25 59.4 5.056 5.279 97.5 10.8 20.8 2024 11 01 19 57.67 +25 35.6 5.139 5.237 90.1 10.9 20.8 2024 11 11 19 57.74 +25 18.1 5.222 5.194 83.0 10.9 20.8 2024 11 21 19 59.10 +25 08.5 5.300 5.153 76.1 10.7 20.8 2024 12 01 20 01.61 +25 08.5 5.369 5.112 69.7 10.4 20.8 2024 12 11 20 05.12 +25 19.3 5.428 5.073 63.9 10.0 20.8 2024 12 21 20 09.45 +25 41.5 5.474 5.034 58.7 9.6 20.8 2024 12 31 20 14.46 +26 16.0 5.506 4.996 54.3 9.2 20.8 2025 01 10 20 20.01 +27 03.1 5.521 4.959 50.8 8.8 20.8 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2024 CBAT 2024 July 9 (CBET 5410) Daniel W. E. Green