C/1885 X1 Fabry
more info
C/1885 X1 was discovered on 1 December 1885 by Louis Fabry (Paris, France), about 5 months before its perihelion passage, and the comet was last seen on 30 July 1886 [Kronk, Cometography: Volume 2].
This comet made its closest approach to the Earth on 1 May 1886 (0.198 au), that is less than two weeks before perihelion passage.
Solutions given here are based on data spanning over 0.630 yr in a range of heliocentric distances from 2.29 au through perihelion (0.642 au) to 2.00 au.
This Oort spike comet suffers small planetary perturbations during its passage through the planetary system; these perturbations lead to escape the comet from the planetary zone on a hyperbolic orbit (see future barycentric orbits).
C/1885 X1 was in the original sample of 19 comets used by Oort for his hypothesis on LPCs; however, according to presented here statistics for previous perihelion passage this comet most probably is dynamically old.
See also Królikowska 2020.

solution description
number of observations 217
data interval 1885 12 01 – 1886 07 19
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 2.29 au – 0.64 au (perihelion) – 2 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 390
RMS [arcseconds] 3.58
orbit quality class 2a
orbital elements (heliocentric ecliptic J2000)
Epoch 1886 04 04
perihelion date 1886 04 06.45438288 ± 0.00028408
perihelion distance [au] 0.64236680 ± 0.00000206
eccentricity 1.00027315 ± 0.00002319
argument of perihelion [°] 126.588371 ± 0.000120
ascending node [°] 37.963059 ± 0.000094
inclination [°] 82.628566 ± 0.000459
recip semi-major axis [10-6 au-1] -425.22 ± 36.10
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/day2] 2.3366 ± 0.2953
A2 [10-8au/day2] -0.28794 ± 0.16058
A3 [10-8au/day2] 0 (assumed)
m -2.15
n 5.093
k -4.6142
r0 [au] 2.808
α 0.1113