Electronic Telegram No. 5120 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/2022 H1 (PANSTARRS) R. Weryk, Department of Physics and Astronomy, University of Western Ontario, reports the discovery of another apparent comet in images obtained on Apr. 21 with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala, noting the object to appear condensed with a coma of size 1".9 in 1".6 seeing (and with no tail) in four 45-s w-band survey images. The discovery images suggest a point-spread-function asymmetry toward the northwest, but there were quality issues with the images. The discovery observations, along with two (presumably asteroidal) pre-discovery Pan-STARRS2 observations from Mar. 2, are tabulated below. 2022 UT R.A. (2000) Decl. Mag. Mar. 2.64387 13 11 34.13 -30 02 19.8 20.8 2.64450 13 11 34.12 -30 02 19.9 20.8 Apr. 21.35854 12 50 35.85 -31 07 11.1 20.6 21.36885 12 50 35.55 -31 07 11.2 20.6 21.37914 12 50 35.29 -31 07 11.2 20.7 21.38944 12 50 35.00 -31 07 11.0 20.5 After the object was posted on the Minor Planet Center's PCCP webpage, H. Sato (Tokyo, Japan) found a strongly condensed coma 4" in diameter and no tail on eight stacked 120-s CCD exposures taken remotely with a 0.51-m f/6.8 astrograph at Siding Spring, NSW, Australia; the magnitude was 19.8 as measured within a circular aperture of radius 3".2. The available astrometry appears on MPEC 2022-J76. The following parabolic orbital elements by S. Nakano (Central Bureau) are from 56 observations spanning 2022 Mar. 2-May 9 (mean residual 0".6); Nakano cautions that these elements are heavily influenced by the Mar. 2 pre-discovery observations, with nothing else until the discovery observations on Apr. 21. T = 2024 Jan. 24.45494 TT Peri. = 246.79164 Node = 6.36521 2000.0 q = 7.6646015 AU Incl. = 49.86647 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 7.5 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 04 11 12 55.30 -31 05.9 7.725 8.653 156.5 2.6 19.4 2022 04 21 12 50.76 -31 07.2 7.700 8.626 155.7 2.7 19.4 2022 05 01 12 46.47 -31 03.8 7.703 8.598 151.0 3.3 19.4 2022 05 11 12 42.63 -30 57.1 7.732 8.571 144.1 4.0 19.4 2022 05 21 12 39.42 -30 48.4 7.787 8.544 136.0 4.7 19.4 2022 05 31 12 36.94 -30 39.2 7.862 8.517 127.5 5.4 19.4 2022 06 10 12 35.28 -30 30.9 7.955 8.491 118.8 6.0 19.4 2022 06 20 12 34.47 -30 24.9 8.062 8.465 110.1 6.5 19.5 2022 06 30 12 34.53 -30 22.2 8.178 8.440 101.5 6.8 19.5 2022 07 10 12 35.42 -30 23.5 8.300 8.415 93.0 6.9 19.5 2022 07 20 12 37.11 -30 29.5 8.422 8.390 84.7 6.9 19.5 2022 07 30 12 39.54 -30 40.6 8.543 8.365 76.6 6.8 19.5 2022 08 09 12 42.64 -30 56.9 8.657 8.341 68.6 6.5 19.6 2022 08 19 12 46.35 -31 18.5 8.762 8.317 60.9 6.1 19.6 2022 08 29 12 50.60 -31 45.5 8.855 8.294 53.5 5.6 19.6 2022 09 08 12 55.32 -32 17.6 8.934 8.271 46.4 5.1 19.6 2022 09 18 13 00.43 -32 54.7 8.996 8.248 39.7 4.5 19.6 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 May 10 (CBET 5120) Daniel W. E. Green