------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 3130 2015 Dec 22 15.20UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK Backup: gmh@wdcc1.bnsc.rl.ac.uk WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- COMET C/2015 X8 (NEOWISE) On Dec. 18, J. Bauer reported to the Minor Planet Center astrometry measured from images of an unknown extended object that was found on infrared images taken with NEOWISE. The listed optical-wavelength magnitude having been roughly estimated based on past NEOWISE cometary observations. 2015 UT R.A. (2000) Decl. Mag. Dec. 14.63534 12 29 57 +32 42.8 16 15.09427 12 29 15 +33 21.3 In response to an appeal by CBAT, H. Sato, Tokyo, Japan, reports that eleven stacked 20-s exposures taken with an iTelescope 0.43-m f/6.8 astrograph (+ luminance filter) at Nerpio, Spain, on Dec. 18.2 UT show the object to be strongly condensed with a round outer coma 25" in diameter and no tail; the w-band magnitude was 15.9 as measured within a circular aperture of radius 12".6. A. Hale, Cloudcroft, NM, USA, reports that he followed the comet visually for about an hour with a 0.41-m reflector; he notes that the comet was very vague and diffuse with just the very slightest central brightening and without condensation, and he measured total visual magnitude 12.8 with coma diameter 2'.4 on Dec. 18.49. CBET 4225 >From available astrometry (spanning Dec. 14-20), the following preliminary parabolic orbital elements were obtained by G. V. Williams, and an ephemeris appeared on MPEC 2015-Y64. T 2015 Oct. 26.08184 TT MPCW q 1.2176331 (2000.0) P Q Peri. 23.26707 -0.97077831 +0.22562781 Node 191.19995 +0.09266563 +0.66664181 e 1.0 Incl. 155.11251 +0.22136519 +0.71040889 Ephemeris: Date TT R. A. (2000) Decl. Delta r Elong. m1 2015 12 06 12 38 35.3 +22 40 39 1.2318 1.3714 75.5 17.8 2015 12 14 12 30 52.1 +31 50 42 1.0595 1.4308 88.8 17.7 2015 12 20 12 19 16.2 +40 58 04 0.9503 1.4796 99.8 17.6 2015 12 21 12 16 30.7 +42 41 36 0.9348 1.4881 101.7 17.6 2015 12 22 12 13 25.7 +44 28 31 0.9201 1.4966 103.6 17.6 2015 12 28 11 44 39.6 +56 08 08 0.8552 1.5496 114.7 17.6 2016 01 05 09 58 56.2 +71 12 36 0.8443 1.6240 125.2 17.7 Editor: Despite the listed magnitudes above from the Minor Planet Center it may be considerably brighter given the report from Alan Hale of Dec 18. Guy M Hurst