Circular No. 5811

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@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)

PERIODIC COMET HELIN-LAWRENCE (1993l) The following additional precise positions have been reported:

1993 UT  α_{2000}  δ_{2000}  m_{1} Observer
Apr. 21.48906 16^{h}55^{m}53.^{s}10 −15^{o}47′10′′.3 17.0 Helin
22.48906 16 55 42.75 −15 47 40.0  _{”}
May 27.64063 16 38 30.50 −16 17 37.7 17.0 Otomo
27.65382 16 38 29.89 −16 17 39.0  _{”}
June 4.54489 16 32 59.18 −16 29 13.8 16  McNaught

E. Helin, K. Lawrence, and M. Nassir (Palomar). 0.46-m Schmidt telescope

pre-discovery films. Measurer J. Alu. S. Otomo (Otomo Observatory, Kiyosato). 0.25-m f/3.4 reflector. Commu-

nicated by S. Nakano. R. H. McNaught (Siding Spring). Uppsala Southern Schmidt telescope.

Observation made during total lunar eclipse.

Orbital elements by B. G. Marsden, Center for Astrophysics, from 9 observations, Apr. 21-June 4:

T = 1993 June 18.0634 TT  ω = 161.^{o}0330
e = 0.310126  Ω = 92.2084 }2000.0
q = 3.081447 AU  i = 9.7937
a = 4.466683 AU n^{o} = 0.1044062 P = 9.440 years
1993 TT α_{2000}  δ_{2000}  Δ  r  ϵ  β  m_{1}
June 2 16^{h}34.^{m}76 −16^{o}25.^{′}2 2.072 3.083 174.^{o}1 1.^{o}9 16.5
12 16 27.92 −16 42.5 2.087 3.082 165.9  4.6 16.5
22 16 21.88 −17 03.8 2.128 3.082 155.5  7.9 16.5
July 2 16 17.30 −17 29.5 2.193 3.082 145.1 10.9 16.6
12 16 14.61 −17 59.6 2.279 3.084 135.1 13.4 16.7
22 16 14.03 −18 33.6 2.383 3.087 125.6 15.5 16.8
Aug. 1 16 15.63 −19 11.1 2.501 3.091 116.6 17.1 16.9
11 16 19.34 −19 51.2 2.629 3.095 108.0 18.1 17.0
21 16 25.02 −20 32.8 2.764 3.101  99.8 18.8 17.1
31 16 32.51 −21 14.9 2.904 3.108  92.0 18.9 17.2
Sept. 10 16 41.60 −21 56.2 3.046 3.115  84.5 18.8 17.4

1993 June 4 Daniel W. E. Green