Central Bureau for Astronomical Telegrams
IAUC 4804: 1989o
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Circular No. 4804
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
PERIODIC COMET BRORSEN-METCALF (1989o)
After unsuccessful searches at several observatories, this
comet has been recovered by E. Helin at Palomar. The following
observations indicate that the prediction on MPC 14486 (elements
on MPC 11523) requires a correction of Delta(T) = -15.6 days.
1989 UT R.A. (1950) Decl. m1 Observer
July 3.76944 0 22 20.20 +10 48 32.1 Jekabsons
3.79931 0 22 25.69 +10 49 36.4 "
4.38333 0 24 17.18 +11 11 21.2 15.0 Helin
4.40677 0 24 21.79 +11 12 17.2 "
6.42153 0 31 03.2 +12 30 34 14.5 Holt
7.31844 0 34 10.24 +13 06 59.5 Shao
7.40382 0 34 28.76 +13 10 29.5 Bus
7.42535 0 34 33.08 +13 11 21.3 "
P. Jekabsons (Perth). Measured by M. P. Candy and G. Lowe.
Very faint pre-recovery images.
E. Helin, B. Roman, C. Mikolajczak, and A. Mejia (Palomar). 0.46-m
Schmidt films. Measured by J. Alu. Object condensed with very
symmetric coma, and a slight hint of a tail to the southwest.
H. E. Holt and K. Zeigler (Palomar). 0.46-m Schmidt films.
Approximate measures by J. Mueller; reduced by D. W. E. Green.
Comet very obvious.
C.-Y. Shao (Oak Ridge). 1.55-m reflector. Vague image; partially
cloudy; twilight.
S. J. Bus (Lowell Observatory, Anderson Mesa Station). 0.33-m
Pluto photographic telescope. Comet very diffuse, difficult to
measure.
Following a suggestion by Z. Sekanina and D. K. Yeomans that
the nongravitational advance or delay of a returning comet can be
related to an asymmetry in the comet's brightness around perihelion,
M. Festou, Besancon Observatory, and H. Rickman and L. Kamel,
Uppsala Observatory, have analyzed the comet's outgassing in 1919
and predicted (in a communication dated July 3) that Delta(T)
at the 1989 return should be in the range -15 to -30 days.
Total visual magnitude estimates: July 7.41 UT, 11.5 (A. Hale,
Las Cruces, NM, 0.41-m reflector; 5' coma); 7.44, 10.4: (C. S.
Morris and R. D. Shaffer, Lockwood Valley, CA, 0.51-m reflector;
5'.0 coma; very poor sky).
1989 July 7 (4804) Daniel W. E. Green
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