C/1947 S1 Bester
more info
Comet C/1947 S1 was discovered on 25 September 1947 by Michiel J. Bester (Boyden Station of Harvard College Observatory, Bloemfontein, South Africa), that is about 4.7 months before perihelion passage, and the comet was last seen on 6 February 1949. [Kronk, Cometography: Volume 4].
This comet made its closest approach to the Earth on 5 April 1948 (0.740 au), that is about 1.5 month after its perihelion passage.
Solutions given here are based on data spanning over 1.356 yr in a range of heliocentric distances from 2.449 au through perihelion (0.748 au) to 4.890 au.
Pure gravitational orbit determined from the available positional measurements (325 observations) give 1a-class orbit.
It was possible to determine the non-gravitational orbit for C/1947 S1 (preferred orbit) where a small decrease of RMS was obtained (from 2.59 arcsec to 2.42 arcsec).
This Oort spike comet suffers moderate planetary perturbations during its passage through the planetary system that lead to escape the comet from the solar system on a hyperbolic orbit (see future barycentric orbits for both models of motion).
More details in Królikowska et al. 2014.

solution description
number of observations 325
data interval 1947 09 28 – 1949 02 06
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 2.45 au – 0.75 au (perihelion) – 4.89 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 543
RMS [arcseconds] 2.42
orbit quality class 1b
orbital elements (heliocentric ecliptic J2000)
Epoch 1948 02 19
perihelion date 1948 02 16.42230919 ± 0.00013783
perihelion distance [au] 0.74810617 ± 0.00000196
eccentricity 1.00023485 ± 0.00001240
argument of perihelion [°] 350.213385 ± 0.000206
ascending node [°] 271.439361 ± 0.000208
inclination [°] 140.568516 ± 0.000062
recip semi-major axis [10-6 au-1] -313.92 ± 16.58
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
non-gravitational parameters
A1 [10-8au\day-2] 2.055 ± 0.207
A2 [10-8au\day-2] -2.3409 ± 0.0649
A3 [10-8au\day-2] 0 (assumed)
m -2.15
n 5.093
k -4.6142
r0 [au] 2.808
α 0.1113