C 2018 V1 MACHHOLZ-FUJIKAWA-IWAMOTO       

= > SKY AND TELESCOPE :

https://www.skyandtelescope.com/astronomy-news/observing-news/machholz-12th-comet/

COMET C/2018 V1 (MACHHOLZ-FUJIKAWA-IWAMOTO)

    Further to CBET 4569, additional physical observations have been reported
by CCD astrometrists.  J.-F. Soulier writes that unfiltered images taken by A.
Maury, J.-B. Vanssay, and himself with a 0.4-m f/5 Ritchey-Chretien reflector
at San Pedro de Atacama, Chile, on Nov. 9.35-9.37 UT show a diffuse coma of
size 2'.4 x 3'.5 with no tail, and they measured magnitude 11.5 in an aperture
of radius 0'.56; follow-up observations taken during Nov. 10.34-10.36 show a
4'.2 x 5'.2 coma with a tail more than 12' long in p.a. 300 degrees, and
the magnitude was 10.2 in the same-sized photometric aperture; similar
exposures taken on Nov. 11.35-11.37 show a 5' x 6' coma with a 13' tail in
p.a. 300 deg (and mag 10.1 in the same-sized photometric aperture).  K.
Kadota, Ageo, Japan, reports that images taken with a 0.25-m f/5 reflector on
Nov. 9.84 UT show a strong central condensation and a coma of diameter 4'.4
and magnitude 10.3, with no tail.
    Visual total-magnitude and coma-diameter estimates:  Nov. 9.22 UT, 9.9,
4' (J. J. Gonzalez, Collada del Fresno, Sierra del Aramo, near Asturias,
Spain, 0.20-m reflector; near-stellar central condensation of mag about 12.5;
altitude 17 degrees with zodiacal light); 10.49, 9.4, 2'.5 (A. Hale,
Cloudcroft, NM, USA, 10x50 binoculars).
    Additional astrometry were published on MPEC 2018-V151.  The following
preliminary parabolic orbital elements by S. Nakano, Sumoto, Japan, are from
313 observations spanning Nov. 7-11:

    T = 2018 Dec.  3.5142 TT         Peri. =  88.8051
                                     Node  = 128.7214  2000.0
    q = 0.386827 AU                  Incl. = 143.9742

    The following ephemeris is from the above elements, with power-law
photometric parameters H = 10.5 and 2.5n = 7.5:

2018 TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase   Mag.
Nov. 11    12 35.75   -01 46.3    1.069    0.698    39.4    64.2   9.5
    12    12 41.75   -01 38.1    1.034    0.679    39.1    66.9   9.3
    13    12 48.25   -01 29.9    0.999    0.660    38.7    69.8   9.1
    14    12 55.31   -01 21.8    0.965    0.641    38.2    73.0   9.0
    15    13 03.00   -01 13.8    0.931    0.621    37.6    76.3   8.8
    16    13 11.39   -01 06.2    0.898    0.603    36.9    79.9   8.6
    17    13 20.55   -00 59.2    0.865    0.584    35.9    83.6   8.4
    18    13 30.58   -00 53.1    0.834    0.566    34.9    87.7   8.2
    19    13 41.53   -00 48.1    0.804    0.548    33.6    91.9   8.1
    20    13 53.50   -00 44.7    0.777    0.530    32.2    96.5   7.9
    21    14 06.54   -00 43.4    0.751    0.513    30.6   101.2   7.7
    22    14 20.68   -00 44.7    0.728    0.496    28.9   106.0   7.5
    23    14 35.92   -00 49.3    0.708    0.480    27.0   111.0   7.4
    24    14 52.21   -00 57.8    0.691    0.465    25.1   115.8   7.2
    25    15 09.42   -01 10.7    0.679    0.451    23.2   120.4   7.1
    26    15 27.37   -01 28.5    0.671    0.438    21.5   124.4   6.9
    27    15 45.79   -01 51.5    0.668    0.426    20.0   127.5   6.8
    28    16 04.37   -02 19.6    0.670    0.415    19.0   129.3   6.8
    29    16 22.76   -02 52.6    0.677    0.406    18.5   129.5   6.7
    30    16 40.62   -03 30.0    0.689    0.399    18.6   128.0   6.7
Dec.  1    16 57.66   -04 11.2    0.707    0.393    19.0   125.0   6.7
     2    17 13.63   -04 55.3    0.728    0.389    19.8   120.8   6.7
     3    17 28.37   -05 41.5    0.754    0.387    20.7   115.7   6.8
     4    17 41.82   -06 29.0    0.784    0.387    21.7   110.0   6.9
     5    17 53.96   -07 17.2    0.816    0.389    22.5   104.0   7.0
     6    18 04.82   -08 05.6    0.851    0.393    23.3    97.9   7.1
     7    18 14.50   -08 53.5    0.888    0.399    23.8    91.9   7.2
     8    18 23.09   -09 40.7    0.926    0.406    24.3    86.1   7.4


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
     superseded by text appearing later in the printed IAU Circulars.

                        (C) Copyright 2018 CBAT
2018 November 11                 (CBET 4572)              Daniel W. E. Green