C/1976 D2 Shuster
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Comet C/1976 D2 was discovered on 25 February 1976, 1.1 yr after perihelion passage, and was last seen on 7 April 1978 [Kronk and Meyer, Cometography: Volume 5].
The comet made its closest approach to the Earth on 3 April 1975 (5.957 au), eleven months before discovery (2.6 months after perihelion passage), and at the moment of discovery it was approaching the next opposition (minimal distance of 6.70 au to the Earth).
Solution given here is based on data spanning over 2.11 yr in a range of heliocentric distances from 7.37 au to 10.13 au.
This Oort spike comet suffers insignificant planetary perturbations during its passage through the planetary system (see original and future orbits).
See also Królikowska 2014 and Królikowska and Dybczyński 2017.

solution description
number of observations 57
data interval 1976 02 25 – 1978 04 07
data type observed only after perihelion (POST)
data arc selection entire data set (STD)
range of heliocentric distances 7.37 au – 10.1au
detectability of NG effects in the comet's motion NG effects not determinable
type of model of motion GR - gravitational orbit
data weighting NO
number of residuals 111
RMS [arcseconds] 1.00
orbit quality class 1a
orbital elements (heliocentric ecliptic J2000)
Epoch 1975 01 28
perihelion date 1975 01 15.54666400 ± 0.01300300
perihelion distance [au] 6.88076913 ± 0.00009833
eccentricity 1.00210991 ± 0.00005133
argument of perihelion [°] 193.427853 ± 0.001429
ascending node [°] 22.786964 ± 0.000179
inclination [°] 112.025871 ± 0.000136
recip semi-major axis [10-6 au-1] -306.64 ± 7.46
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