value unc_up unc_lo author ref method 2.0300e+18 nan nan Folkner 2014IPNPR.196C...1F Ephem 7.3860e+18 2.5110e+18 2.5110e+18 Fienga 2020MNRAS.492..589F Ephem 8.6100e+17 5.0000e+18 5.0000e+18 Zielenbach 2011AJ....142..120Z Deflec