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IAUC 2710: P/SCHWASSMANN-WACHMANN 1; 1953 RA; 1949 HC; Occn OF BD +13 1940 BY 129 ANTIGONE ON 1974 Oct. 12

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                                                  Circular No. 2710
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Cable Address: SATELLITES, NEWYORK
Western Union: RAPID SATELLITE CAMBMASS


PERIODIC COMET SCHWASSMANN-WACHMANN 1
     The following precise positions have been obtained by R. E.
McCrosky, C. Y. Shao, G. Schwartz and J. Bulger with the 155-cm
reflector at Harvard College Observatory's Agassiz Station.  On July
20 the well-condensed nucleus was embedded in a uniformly bright,
circular coma some 25" in diameter; on July 21 the coma was somewhat
expanded.  The shorter exposure on Aug. 12 showed only a trace
of a faint coma.  On Sept. 15 there was a sharp, stellar nucleus,
of m2 = 15.7, and a faint, asymmetrical coma over p.a. 50o to 160o;
at p.a. 50o there appeared to be a spike or tail some 30" in
length.  In mid-October the comet was at its normal brightness.

     1974 UT             R. A. (1950) Decl.         m2
     July 17.32199    23 35 58.42   + 2 42 07.4
          20.20731    23 35 43.81   + 2 45 38.9    16.0
          21.19502    23 35 37.53   + 2 46 45.2    16.8
          21.21831    23 35 37.34   + 2 46 43.2
     Aug. 11.31517    23 30 58.03   + 2 52 47.8
          12.22881    23 30 40.32   + 2 52 22.1    17.5
          12.24201    23 30 40.05   + 2 52 21.9
          15.24097    23 29 38.48   + 2 50 31.5
          22.21273    23 26 59.74   + 2 44 00.4


1953 RA
     This member of the Amor group, not observed since 1953 (cf.
Minor Planet Circ. No. 3015), has been recovered by McCrosky,
Schwartz and Bulger with the 155-cm reflector some 0o.3 from an
unpublished prediction by B. G. Marsden:

     1974 UT          R. A. (1950) Decl.      Mag.
     Oct. 18.33127    6 55.2     +38 32      >19
          23.23919    6 56.9     +38 56      ~19.5

     1974/75 ET  R. A. (1950) Decl.     Delta     r     Mag.
     Oct. 20     6 55.93    +38 40.6    1.917   2.364   19.4
          30     6 57.91    +39 33.1
     Nov.  9     6 55.78    +40 28.3    1.777   2.460   19.3
          19     6 49.26    +41 21.7
          29     6 38.55    +42 05.9    1.688   2.551   19.1
     Dec.  9     6 24.46    +42 32.1
          19     6 08.50    +42 33.6    1.689   2.636   19.0
          29     5 52.68    +42 08.2
     Jan.  8     5 38.85    +41 20.1    1.805   2.716   19.3
          18     5 28.30    +40 17.3
          28     5 21.59    +39 08.5    2.025   2.791   19.7

       Mag. = 15.6 + 5 log Delta + 5 log r + 0.023 (phase angle)


1949 HC
     This object, not observed since 1949, has been recovered by
McCrosky, Shao and Bulger as follows:

     1974 UT          R. A. (1950) Decl.      Mag.
     Oct. 18.25926    2 56.0     +20 35       18
          22.35753    2 53.0     +20 05

The positions are within some 0o.3 of an unpublished prediction by
C. M. Bardwell, Minor Planet Center, Cincinnati Observatory.  Of
the minor planets that may be librating around the 2:1 resonance
with Jupiter, only 1362 Griqua and now 1949 HC (which has e = 0.47,
Incl. = 35o) have been observed at more than one opposition (but note
also 1973 SE, IAUC 2608).  Further observations are desired.

     1974/75 ET  R. A. (1950) Decl.     Delta     r     Mag.
     Oct. 20     2 54.70    +20 22.1    3.138   4.080   18.6
          30     2 46.99    +19 06.6
     Nov.  9     2 39.13    +17 47.2    3.150   4.140   18.5
          19     2 31.70    +16 28.0
          29     2 25.24    +15 13.2    3.294   4.196   18.7
     Dec.  9     2 20.13    +14 06.3
          19     2 16.61    +13 10.0    3.551   4.250   19.0
          29     2 14.79    +12 25.2
     Jan.  8     2 14.61    +11 52.2    3.884   4.302   19.3

        Mag. = 12.9 + 5 log Delta + 5 log r + 0.023 (phase angle)


OCCULTATION OF BD +13 1940 BY 129 ANTIGONE ON 1974 OCTOBER 12
     Negative observations (cf. IAUC 2706) have been received from
K. Simmons, R. Sweetsir and K. Kirk (near Jacksonville, Florida);
H. Povenmire (near Hollywood, Florida); P. and M. J. Taylor (Boynton
Beach, Florida); P. Maley (Houston, Texas); and M. Mattei
(Harvard, Mass.).  A calculation by the undersigned, utilizing
observations 1968-1971 and one by R. E. McCrosky at Harvard on 1974
Oct. 11, suggests that the occultation may have taken place in
Ecuador, Colombia and Brazil.


1974 October 24                (2710)              Brian G. Marsden

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