C/1890 F1 Brooks
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C/1890 F1 was discovered on 20 March 1890 by William Robert Brooks (Smith Observatory at Hobart College, Geneva, New York, USA), that is about 2.5 months before its perihelion passage, and it was last seen on 5 February 1892 [Kronk, Cometography: Volume 2].
This comet made its closest approach to the Earth on 4 June 1890 (1.565 au), that is a day after perihelion passage.
The original positions of this comet were recalculated using modern star catalogues. Some extensive material of data processing is available at WikiComet.
Solutions given here are based on data spanning over 1.88 yr in a range of heliocentric distances from 2.10 au through perihelion (1.908 au) to 6.56 au.
This Oort spike comet suffers tiny planetary perturbations during its passage through the planetary system; these perturbations lead to a little bit shorter future semimajor axis (see future barycentric orbits).
C/1890 F1 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, dynamical status of this comet is uncertain - new calculations shows that its previous perihelion distance was about 14.3 au (nominal orbit).
See also Królikowska and Dybczyński 2016.

solution description
number of observations 908
data interval 1890 03 22 – 1892 02 05
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 2.1 au – 1.91 au (perihelion) – 6.56 au
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 1644
RMS [arcseconds] 2.61
orbit quality class 1a
orbital elements (heliocentric ecliptic J2000)
Epoch 1890 06 02
perihelion date 1890 06 02.03768156 ± 0.00023607
perihelion distance [au] 1.90758152 ± 0.00000173
eccentricity 1.00033162 ± 0.00000658
argument of perihelion [°] 68.927751 ± 0.000116
ascending node [°] 321.877680 ± 0.000037
inclination [°] 120.568896 ± 0.000037
recip semi-major axis [10-6 au-1] -173.84 ± 3.45
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