C/2000 A1 Montani
more info
C/2000 A1 was discovered on 12 January 2000 by J. Montani on CCD images taken using the Spacewatch telescope at Kitt Peak as cometary object [IAUC 7346, 2000 January 14]. After preliminary orbit computations it was found that Spacewatch and LINEAR survey registered this object on pre-discovery images taken 8 and 7 days before.
This comet made its closest approach to the Earth on 20 January 2000 (8.809 au), 5.7 months before perihelion.
Solution given here is based on data spanning over 2.2 yr in a range of heliocentric distances: 9.80 au – 9.743 au (perihelion) – 10.3 au.
This Oort spike comet suffers slight planetary perturbations during its passage through the planetary system.
See also Królikowska 2014 and Królikowska and Dybczyński 2017.

solution description
number of observations 132
data interval 2000 01 04 – 2002 03 20
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 9.8 au – 9.74 au (perihelion) – 10.3 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 264
RMS [arcseconds] 0.45
orbit quality class 1a
orbital elements (heliocentric ecliptic J2000)
Epoch 2000 06 25
perihelion date 2000 07 13.13741400 ± 0.01117800
perihelion distance [au] 9.74312736 ± 0.00002922
eccentricity 1.00388320 ± 0.00001921
argument of perihelion [°] 14.265914 ± 0.000509
ascending node [°] 111.835674 ± 0.000042
inclination [°] 24.542798 ± 0.000049
recip semi-major axis [10-6 au-1] -398.56 ± 1.97
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