(60558) Echeclus
This object has a more recent orbit available here
Object
Object | (60558) Echeclus |
Diameter(1) | 64 km |
Dynamic class(1) | Centaur |
Absolute magnitude | 9.50 |
G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
Epoch (Julian date) | 2458600.5 |
Semi major axis | 10.690937 ± 0.000001 au |
Eccentricity | 0.456454696 ± 0.000000074 |
Inclination | 4.343405950 ± 0.000001266 ° |
Longitude of ascending node | 173.303957 ± 0.000046 ° |
Argument of perihelia | 162.808699 ± 0.000046 ° |
Mean anomaly | 41.343953 ± 0.000010 ° |
Orbital period | 34.96 yr |
Ephemeris & Observations
Ephemeris version | NIMAv8 |
Observation file |
omc_ast_NIMAv8.txt |
bsp file | 60558_Echeclus_nima_v8.bsp |
Date of first observation | 1979-09-23 |
Date of last observation | 2021-01-19 |
Number of observations used in the fit | 4259 |
Number of rejected observations | 176 |
Number of DES observations | 0 |
Number of MPC observations | 4253 |
Number of unpublished observations | 182 |
RMS of observations | 0.466 arcsec |
Residuals

Residuals in right ascension and declination compared to NIMAv8 ephemeris.
Colours indicate the estimated precision in arcsec used as weights in the fitting process.
Orbit quality
date | σα (arcsec) | σδ (arcsec) |
2021-01 | 0.004 | 0.003 |
2021-07 | 0.005 | 0.003 |
2022-01 | 0.007 | 0.005 |
2022-07 | 0.007 | 0.005 |
2023-01 | 0.010 | 0.006 |
2023-07 | 0.010 | 0.006 |
2024-01 | 0.014 | 0.008 |
2024-07 | 0.013 | 0.007 |
2025-01 | 0.017 | 0.009 |
Ephemeris comparison

Difference between NIMAv8 and JPL90 in right ascension (weighted by cos δ) and in declination.
Gray area represents the 1-σ uncertainty of NIMA ephemeris. Green dots represent the DES observations.