C/1973 A1 Heck-Sause
more info
Comet C/1973 A1 was discovered on 11 January 1973 by André Heck and Gérard Sause (Haute Provence Observatory, France), that is more than 3 months after its perihelion passage.In the next few months prediscovery images were found taken on 4 January (Sendai Municipal Observatory, Japan) and 10 January (Montpellier, France). This comet was observed until 26 February 1974 [Kronk, Cometography: Volume 5].
Comet had its closest approach to the Earth on 11 February 1973 (1.978 au), a month after its discovery.
Solution given here is based on post-perihelion data spanning over 1.13 yr in a range of heliocentric distances from 2.70 au to 5.53 au.
This Oort spike comet suffers rather small planetary perturbations during its passage through the planetary system; these perturbations lead to a more tight future orbit.
See also Królikowska 2020.

solution description
number of observations 201
data interval 1973 01 04 – 1974 02 19
data type observed only after perihelion (POST)
data arc selection entire data set (STD)
range of heliocentric distances 2.7 au – 5.53au
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 400
RMS [arcseconds] 1.24
orbit quality class 1b
next orbit statistics, both Galactic and stellar perturbations were taken into account
no. of returning VCs in the swarm 5001 *
no. of escaping VCs in the swarm 0
no. of hyperbolas among escaping VCs in the swarm 0
next reciprocal semi-major axis [10-6 au-1] 362.88 – 378.33 – 394.11
next perihelion distance [au] 2.51452 – 2.51457 – 2.5146
next aphelion distance [103 au] 5.07 – 5.28 – 5.51
time interval to next perihelion [Myr] 0.127 – 0.135 – 0.144
percentage of VCs with qnext < 10100
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.
next orbit statistics, here only the Galactic tide has been included
no. of returning VCs in the swarm 5001 *
no. of escaping VCs in the swarm 0
no. of hyperbolas among escaping VCs in the swarm 0
next reciprocal semi-major axis [10-6 au-1] 362.90 – 378.34 – 394.13
next perihelion distance [au] 2.5093 – 2.50956 – 2.50978
next aphelion distance [103 au] 5.07 – 5.28 – 5.51
time interval to next perihelion [Myr] 0.127 – 0.135 – 0.144
percentage of VCs with qnext < 10100