astroforge.common.R_sun

astroforge.common.R_sun(time)

Low fidelity position of Sun in GCRS (Montenbruck & Gill, p. 70). The input time is given in MJD. The output units are in km. The longitude, lambda, and the position vector, r, refer to the mean equinox and ecliptic of J2000. A modification of M to match JPL430 was necessary to have the correct sidereal year.From the mean longitude referred to the mean ecliptic and the equinox J2000 given in Simon et al., 1994, Astron. Astrophys., 282, 663. It is possible tha Montenbruck & Gill mistakenly used the anomalistic year instead of the sidereal year for lambda.