Central Bureau for Astronomical Telegrams
IAUC 3545: Sats OF SATURN; NEW METEOR SHOWER; P/ENCKE
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Circular No. 3545
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
SATELLITES OF SATURN
J. Lecacheux, Meudon Observatory, reports: "1980 S 13 (cf.
IAUC 3534) was probably recorded on electronographic plates by D.
Michet, L. Renard, B. Servan and G. Wlerick using the Haute-Provence
1.9-m reflector on Mar. 16, and by J. Baudrand, A. Chevillot
and P. Felenbok at the prime focus of the Canada-France-Hawaii
reflector on May 19. Because the plates were underexposed, these
images are ill-defined and were neglected in previous analyses. The
observed positions (accuracy 0".5) are: Mar. 16.010 UT, 36".3 east;
May 19.340, 31".5 east. Assuming that the orbit is circular, two
different solutions for the time of greatest eastern elongation
appear to represent the eight reported observations (see also IAUC
3466, 3484, 3496):
I: 1980 Mar. 12.196 + light-time + 0.0055 (U-45o.6) + 1.9956 E
II: 1980 Mar. 12.498 + light-time + 0.0051 (U-45o.6) + 1.8388 E
Solution I is very close to the solution proposed by Pascu et al.
(IAUC 3534) and represents observed positions within 1".5 (standard
deviation). Solution II fits the observed positions within 0".6 and
therefore appears more probable. Re-examination of Lelievre's Apr.
12.028 plate (cf. IAUC 3484) reveals a faint trace of 1980 S 6 at
34".8 west of Saturn; the position of the faint, poorly-defined
feature 1980 S 24 is revised to be 41".4 west of Saturn. As pointed
out by Pascu et al. (IAUC 3534), 1980 S 24, if real, can be identified
with 1980 S 13. On the other hand, the identification 1980 S
18 = 1980 S 6 appears very doubtful. If Solution II is correct,
1980 S 13 revolves at 5100 km inside the orbit of Saturn III
(Tethys) and is almost in 3:2 resonance with Saturn IV (Dione)."
NEW METEOR SHOWER
P. Roggemans, Mechelen, Belgium, writes that his observations
in late Sept. and observations by several Belgian meteor observers
during Oct. 2-6 do not reveal any meteors from the radiant reported
by MacKinnon and Keen (IAUC 3528).
PERIODIC COMET ENCKE
Total visual magnitude estimates and coma diameters: Nov.
12.23, 6.8, 6'.0 (G. S. Keitch, Wrington, Eng., 10 x 50 binoculars);
19.43, 6.7, 2'.6 (J. Bortle, Stormville, NY, 20 x 80 binoculars).
1980 November 26 (3545) Daniel W. E. Green
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