Electronic Telegram No. 5067 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/2021 V1 (RANKIN) David Rankin reports his discovery of a comet with a coma of size of 4".8 visible in each of the four discovery 30-s CCD images obtained on Nov. 5 with the Mt. Lemmon 1.5-m reflector (discovery observations tabulated below). 2021 UT R.A. (2000) Decl. Mag. Observer Nov. 5.16078 23 27 04.37 +33 50 54.9 20.9 Rankin 5.16600 23 27 04.36 +33 50 47.5 20.6 " 5.17122 23 27 04.29 +33 50 39.8 20.7 " After the comet was posted on the Minor Planet Center's PCCP webpage, H. Sato, Tokyo, Japan, reported that twenty-four stacked 60-s CCD exposures taken on Nov. 6.15-6.17 UT with a 0.43-m f/6.8 astrograph located near Mayhill, NM, USA, show a strongly condensed coma 8" in diameter with no tail; the magnitude was 20.3 as measured within a circular aperture of radius 5".7. The available astrometry appears on MPEC 2021-V167, including two sets of single-night astrometry from the Mt. Lemmon survey from Oct. 2.2 (at mag 20.6- 21.2) and 24.2 UT (mag 20.4-21.0) that were in the MPC's "isolated tracklet file" under two separate designations. The following parabolic orbital elements by S. Nakano (CBAT) are from 40 observations spanning Oct. 2-Nov. 7 (mean residual 0".6). T = 2022 Apr. 30.21547 TT Peri. = 195.08792 Node = 207.61869 2000.0 q = 3.0147465 AU Incl. = 71.49664 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 13.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2021 11 02 23 27.53 +35 04.9 2.717 3.487 134.7 11.7 19.5 2021 11 07 23 26.91 +33 07.8 2.723 3.463 131.8 12.3 19.5 2021 11 12 23 26.86 +31 10.6 2.737 3.440 128.3 13.0 19.5 2021 11 17 23 27.36 +29 14.8 2.758 3.417 124.5 13.8 19.5 2021 11 22 23 28.40 +27 21.5 2.786 3.395 120.4 14.5 19.5 2021 11 27 23 29.95 +25 31.7 2.820 3.373 116.1 15.2 19.5 2021 12 02 23 31.98 +23 46.4 2.860 3.352 111.7 15.9 19.5 2021 12 07 23 34.46 +22 06.1 2.905 3.331 107.1 16.4 19.5 2021 12 12 23 37.38 +20 31.4 2.954 3.311 102.6 16.9 19.5 2021 12 17 23 40.69 +19 02.6 3.006 3.291 98.0 17.2 19.5 2021 12 22 23 44.36 +17 39.7 3.062 3.272 93.5 17.5 19.5 2021 12 27 23 48.36 +16 22.9 3.119 3.253 88.9 17.6 19.6 2022 01 01 23 52.67 +15 11.9 3.179 3.235 84.5 17.6 19.6 2022 01 06 23 57.27 +14 06.6 3.239 3.218 80.0 17.5 19.6 2022 01 11 00 02.13 +13 06.8 3.300 3.201 75.7 17.3 19.6 2022 01 16 00 07.22 +12 12.1 3.360 3.185 71.4 17.0 19.7 2022 01 21 00 12.53 +11 22.3 3.420 3.170 67.1 16.6 19.7 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2021 CBAT 2021 November 8 (CBET 5067) Daniel W. E. Green