C/1937 N1 Finsler
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Comet C/1937 N1 was discovered on 4 July 1937 by Paul Finsler (Zürich, Switzerland), that is about 1.5 months before its perihelion passage, and the comet was last seen on 30 December 1937 [Kronk, Cometography: Volume 4].
This comet made its closest approach to the Earth on 9 August 1937 (0.548 au), that is 6 days before perihelion passage.
Solutions given here are based on data spanning over 0.490 yr in a range of heliocentric distances from 1.144 au through perihelion (0.863 au) to 2.355 au.
Pure gravitational orbit determined from all available positional measurements (417 observations) give 2a-class orbit similarly as in Minor Planet Center (212 obs. used, the same arc of data; 2A-class, see MPC).
It was possible to determine the non-gravitational orbit for C/1937 N1 (preferred orbit); the derived NG solution give significantly different original and future 1/a as in the case of pure gravitational model of motion.
This comet suffers rather small planetary perturbations during its passage through the planetary system. However, the change of 1/a due to these perturbations turned out to be quite different in both models of motion (see original and future barycentric orbits in both solutions).
More details in Królikowska et al. 2014.

solution description
number of observations 413
data interval 1937 07 04 – 1937 12 30
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 1.14 au – 0.86 au (perihelion) – 2.36 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 766
RMS [arcseconds] 1.92
orbit quality class 2b
orbital elements (barycentric ecliptic J2000)
Epoch 1633 10 27
perihelion date 1937 08 15.66152712 ± 0.00165550
perihelion distance [au] 0.85934606 ± 0.00002184
eccentricity 0.99956398 ± 0.00008654
argument of perihelion [°] 114.991035 ± 0.002703
ascending node [°] 59.472210 ± 0.000809
inclination [°] 146.363379 ± 0.000573
reciprocal semi-major axis [10-6 au-1] 507.39 ± 100.71
file containing 5001 VCs swarm
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.
Six 2D-projections of the 6D space of original swarm including 5001 VCs. Each density map is given in logarithmic scale presented on the right in the individual panel.