Electronic Telegram No. 5734 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/2026 P2 (PANSTARRS) R. Weryk, Department of Physics and Astronomy, University of Western Ontario, reports the discovery of another comet in images obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala, HI, USA (discovery observations tabulated below). Four stacked 45-s w-band survey images taken in 1".0-1".2 seeing show a very condensed head of size 2".0 (full-width-at- half-maximum), with a broad 25"-long tail spanning p.a. 210-240 degrees. 2026 UT R.A. (2000) Decl. Mag. Aug. 11.55564 2 01 45.97 - 2 31 56.5 19.9 11.56950 2 01 45.83 - 2 31 54.9 19.9 11.58344 2 01 45.74 - 2 31 54.3 19.8 11.59738 2 01 45.60 - 2 31 52.9 20.0 Three follow-up 60-s gri-band exposures that were obtained by Weryk and R. Wainscoat with the 3.6-m Canada-France-Hawaii Telescope on Aug. 12.59 UT (queue observer A. Acohido; queue coordinator J. Ou) in 0".7 seeing show a very condensed head of size 1".5 and mag 20.4-20.5 with a broad 30"-long tail spanning p.a. 205-230 degrees. Weryk subsequently found pre-discovery Pan-STARRS1 images of this comet from 2025 Aug. 25.6 (at mag 21.7-22.1), Aug. 30.6 (mag 22.2-22.6), Sept. 15.5 (mag 21.2-23.0), Nov. 11.3 (mag 20.9-21.7), and Nov. 24.3 (mag 20.6-21.3). After the comet was posted to the Minor Planet Center's PCCP webpage, other astrometrists have reported physical appearance to the Central Bureau. Seven stacked 60-s CCD exposures taken remotely by H. Sato (Bunkyo-ku, Tokyo, Japan) on 2026 Aug. 13.67 UT with a 0.51-m f/6.8 astrograph located at Siding Spring, NSW, Australia, show a strongly condensed, fuzzy coma 8" in diameter with no tail; the magnitude was 18.7 as measured within a circular aperture of radius 4".3. Ten 120-s CMOS exposures taken remotely by T. Prystavski (Lviv, Ukraine) using an iTelescope 0.36-m f/7.2 "corrected" Dall-Kirkham telescope located in the Rio Hurtado Valley, Chile, on Aug. 24.4 in morning twilight clearly show cometary appearance; a stacked image shows a condensed coma of size 10" (magnitude 18.2) with a tail 22" long in p.a. 204 degrees. Nine stacked 300-s luminance-filtered CCD exposures taken remotely by F. D. Romanov (Yuzhno-Morskoy, Nakhodka, Russia) on Aug. 31.76 using an iTelescope 0.43-m telescope at Siding Spring show a very condensed coma of diameter 6" (magnitude 18.7). The available astrometry appears on MPEC 2026-R102. The following orbital elements by S. Nakano (Central Bureau) are from 251 observations spanning 2025 Aug. 25-2026 Sept. 8 (mean residual 0".4), with corresponding "original" and "future" values of 1/a being +0.000577 and -0.002144 (+/- 0.000008) AU**-1, respectively. The comet passed 4.16 AU from Saturn on 2026 Mar. 8 and will pass 0.32 AU from Jupiter on 2029 Apr. 15 UT. Epoch = 2027 Nov. 11.0 TT T = 2027 Nov. 21.73949 TT Peri. = 78.89739 e = 0.9995145 Node = 23.44518 2000.0 q = 2.4799438 AU Incl. = 63.02699 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 9.5 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2026 08 28 01 57.80 -02 15.1 4.468 5.134 126.6 9.1 18.4 2026 09 07 01 53.45 -02 08.5 4.274 5.057 136.9 7.8 18.3 2026 09 17 01 47.61 -02 03.3 4.103 4.980 147.4 6.2 18.1 2026 09 27 01 40.41 -01 57.8 3.959 4.903 157.9 4.4 18.0 2026 10 07 01 32.08 -01 50.3 3.846 4.825 167.1 2.6 17.9 2026 10 17 01 22.99 -01 39.0 3.765 4.748 169.3 2.2 17.8 2026 10 27 01 13.61 -01 22.1 3.719 4.671 161.3 3.9 17.7 2026 11 06 01 04.48 -00 58.2 3.705 4.594 150.4 6.1 17.6 2026 11 16 00 56.10 -00 26.4 3.723 4.517 139.1 8.2 17.6 2026 11 26 00 48.89 +00 13.8 3.766 4.440 127.8 10.1 17.6 2026 12 06 00 43.14 +01 02.4 3.830 4.364 116.8 11.6 17.5 2026 12 16 00 39.03 +01 59.0 3.909 4.287 106.1 12.7 17.5 2026 12 26 00 36.61 +03 03.2 3.997 4.211 95.8 13.4 17.5 2027 01 05 00 35.83 +04 14.5 4.088 4.135 85.9 13.7 17.5 2027 01 15 00 36.62 +05 32.5 4.177 4.060 76.4 13.6 17.5 2027 01 25 00 38.82 +06 56.7 4.260 3.985 67.3 13.2 17.5 2027 02 04 00 42.31 +08 26.8 4.333 3.910 58.5 12.4 17.4 2027 02 14 00 46.94 +10 02.5 4.392 3.836 50.2 11.4 17.4 2027 02 24 00 52.59 +11 43.8 4.436 3.762 42.2 10.2 17.3 2027 06 04 02 27.31 +33 58.3 3.888 3.080 32.4 10.2 16.4 2027 06 14 02 40.01 +36 53.2 3.752 3.020 38.2 12.0 16.2 2027 06 24 02 53.42 +39 58.7 3.607 2.962 44.0 13.8 16.1 2027 07 04 03 07.68 +43 15.9 3.458 2.906 49.7 15.5 15.9 2027 07 14 03 22.99 +46 45.7 3.307 2.853 55.3 17.0 15.7 2027 07 24 03 39.62 +50 28.7 3.156 2.802 60.7 18.4 15.6 2027 08 03 03 58.05 +54 25.4 3.009 2.754 65.8 19.6 15.4 2027 08 13 04 18.99 +58 34.9 2.870 2.710 70.7 20.7 15.3 2027 08 23 04 43.66 +62 55.0 2.740 2.668 75.3 21.5 15.1 2027 09 02 05 14.24 +67 20.8 2.623 2.631 79.3 22.1 15.0 2027 09 12 05 54.73 +71 42.7 2.522 2.597 82.9 22.6 14.8 2027 09 22 06 52.75 +75 42.7 2.437 2.567 85.8 23.0 14.7 2027 10 02 08 20.01 +78 45.8 2.370 2.541 88.0 23.2 14.6 2027 10 12 10 17.97 +79 58.3 2.320 2.519 89.6 23.3 14.5 2027 10 22 12 11.90 +78 57.4 2.286 2.503 90.6 23.4 14.5 2027 11 01 13 32.70 +76 33.1 2.266 2.490 91.0 23.5 14.4 2027 11 11 14 25.83 +73 43.8 2.258 2.483 91.1 23.5 14.4 2027 11 21 15 02.48 +71 01.9 2.257 2.480 91.0 23.5 14.4 2027 12 01 15 29.38 +68 42.9 2.261 2.482 91.0 23.4 14.4 2027 12 11 15 49.87 +66 54.6 2.268 2.489 91.1 23.3 14.4 2027 12 21 16 05.62 +65 40.1 2.274 2.500 91.4 23.2 14.5 2027 12 31 16 17.36 +65 00.7 2.279 2.517 92.2 23.0 14.5 2028 01 10 16 25.11 +64 55.7 2.282 2.537 93.4 22.8 14.5 2028 01 20 16 28.49 +65 22.7 2.282 2.562 95.0 22.5 14.6 2028 01 30 16 26.62 +66 17.5 2.282 2.592 96.9 22.2 14.6 2028 02 09 16 18.03 +67 32.8 2.282 2.625 99.1 21.8 14.6 2028 02 19 16 00.89 +68 56.5 2.285 2.662 101.4 21.3 14.7 2028 02 29 15 33.37 +70 10.9 2.295 2.703 103.5 20.9 14.8 2028 03 10 14 55.32 +70 51.4 2.314 2.747 105.2 20.4 14.8 2028 03 20 14 10.63 +70 33.2 2.345 2.795 106.4 20.0 14.9 2028 03 30 13 26.80 +69 02.9 2.393 2.845 106.7 19.7 15.0 2028 04 09 12 50.58 +66 25.0 2.458 2.898 105.9 19.4 15.1 2028 04 19 12 24.33 +62 57.5 2.543 2.953 104.2 19.3 15.3 2028 04 29 12 07.06 +58 59.6 2.647 3.011 101.3 19.1 15.4 2028 05 09 11 56.79 +54 47.7 2.769 3.071 97.6 19.0 15.6 2028 05 19 11 51.62 +50 33.5 2.909 3.133 93.2 18.8 15.8 2028 05 29 11 50.13 +46 24.4 3.063 3.196 88.2 18.5 16.0 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2026 CBAT 2026 September 8 (CBET 5734) Daniel W. E. Green