[Iaude] CBET 4793: COMET 246P/NEAT
quai at eps.harvard.edu
quai at eps.harvard.edu
Tue Jun 9 16:21:26 EDT 2020
Electronic Telegram No. 4793
Central Bureau for Astronomical Telegrams
Mailing address: Hoffman Lab 209; Harvard University;
20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbatiau at eps.harvard.edu (alternate cbat at iau.org)
Prepared using the Tamkin Foundation Computer Network
M. Jaeger, Vienna, Austria, reports that he has detected an unsually
long, thin dust tail emanating from the coma of comet 246P on stacked 100-s
CCD images taken with a Celestron 28-cm Rowe-Ackermann Schmidt Astrograph on
Apr. 15.95, Apr. 25.93, May 12.89, and May 17.94 UT. On the Apr. 15 (nineteen
stacked exposures) and Apr. 25 (twenty-nine stacked exposures) images, the
tail was measured to be 100' long in p.a. 297 degrees, with a 10' gap near
the head of the comet and with the tail being brightest at 30'-50' from the
coma; the first 3'.5 of tail was in p.a. 280 deg, prior to the gap. On May
17, twenty-three stacked 100-s exposures show a tail longer than 2.2 degrees
(going outside the field-of-view) in p.a. 293 degrees.
Total-magnitude and coma-diameter estimates of comet 246P (visual
unless noted otherwise): Feb. 23.62, 15.4, -- (K. Kadota, Ageo, Japan,
0.25-m reflector + CCD); 29.77, 15.3, -- (Kadota); Apr. 4.59, 14.7, --
(Kadota); 19.43, 14.8, 0'.6 (C. Wyatt, Walcha, NSW, Australia, 0.40-m
reflector); 22.43, 14.7, 0'.9 (Wyatt); 24.43, 15.0, 0'.4 (Wyatt); May 11.46,
14.5, 0'.5 (P. Camilleri, Katherine, NT, Australia, 0.40-m reflector); 13.51,
14.3, 0'.6 (Camilleri); 14.27, 15.2, 0'.6 (C. S. Morris, Fillmore, CA, U.S.A.,
41-cm reflector + CCD); 16.33, 15.3, 0'.6 (Morris); 17.20, 15.4, 0'.48
(Morris); 17.39, 14.6, 0'.5 (Wyatt, 25-cm reflector); 21.31, 15.2, 0'.7
(Morris); 21.88, 13.5, 0'.4 (W. Hasubick, Buchloe, Germany, 44-cm reflector);
24.47, 14.2, 0'.8 (Camilleri).
The comet's brightness is close to the predictions (magnitude = 7.5 +
5 log Delta + 10 log r) in the ICQ's 2020 Comet Handbook. CCD observers are
encouraged to follow the comet's long tail as long as possible, though
wide-field Schmidt telescopes in dark-sky locations would appear to be the
best instruments for success.
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2020 CBAT
2020 June 9 (CBET 4793) Daniel W. E. Green
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