C/1940 S1 Okabayashi-Honda
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Comet C/1940 S1 was discovered on 30 September 1940 by Shigeki Okabayashi (Kurashiki Observatory, Japan), and indeendently, on 3 October by Minoru Honda (Zodiakal Light Observatory, Seto, Japan).At the moment of discovery, this comet was is 1.5 month after perihelion passage, and it was last seen on 3 January 1941. [Kronk, Cometography: Volume 4].
This comet made its closest approach to the Earth on 30 May 1940 (1.194 au), that is 4 months before its discovery.
Solution given here is based on data spanning over 0.249 yr in a range of heliocentric distances from 1.35 au to 2.38 au.
This comet suffers moderate planetary perturbations during its passage through the planetary system that lead to escape the comet from the planetary zone on a hyperbolic orbit (see future barycentric orbit).
More details in Królikowska et al. 2014.

solution description
number of observations 36
data interval 1940 10 04 – 1941 01 03
data type observed only after perihelion (POST)
data arc selection entire data set (STD)
range of heliocentric distances 1.34 au – 2.37au
detectability of NG effects in the comet's motion NG effects not determinable
type of model of motion GR - gravitational orbit
data weighting YES
number of residuals 61
RMS [arcseconds] 2.67
orbit quality class 2b
orbital elements (heliocentric ecliptic J2000)
Epoch 1940 07 30
perihelion date 1940 08 15.74151989 ± 0.01871972
perihelion distance [au] 1.06134353 ± 0.00042312
eccentricity 1.00101170 ± 0.00044419
argument of perihelion [°] 329.641162 ± 0.036347
ascending node [°] 128.060306 ± 0.006071
inclination [°] 133.112612 ± 0.001116
recip semi-major axis [10-6 au-1] -953.22 ± 418.31
Time distribution of positional observations with corresponding heliocentric (red curve) and geocentric (green curve) distance at which they were taken. The horizontal dotted line shows the perihelion distance for a given comet whereas vertical dotted line – the moment of perihelion passage