from astropy.coordinates import SkyCoord, BarycentricMeanEcliptic, get_body_barycentric
from astropy.time import Time
import astropy.units as u

now = Time.now()
mars_icrs = SkyCoord(get_body_barycentric('mars', now), frame='icrs')
mars_ecliptic = mars_icrs.transform_to(BarycentricMeanEcliptic())
print(f"observation time: {now.iso[:19]}")

print(f"mars ICRS coordinate")
print(f"RA = {mars_icrs.ra.to_string(unit=u.hourangle, sep=':', precision=2)}")
print(f"DEC = {mars_icrs.dec.to_string(unit=u.deg, sep=':', precision=1)}")

print(f"mars BarycentricMeanEcliptic coordinate:")
print(f"longitude = {mars_ecliptic.lon.to_string(unit=u.deg, sep=':', precision=2)}")
print(f"latitude = {mars_ecliptic.lat.to_string(unit=u.deg, sep=':', precision=2)}")

print(f"distance to the origin (solar system center of mass):")
print(f"ICRS: {mars_icrs.distance.to('AU'):.8f}")
print(f"BarycentricMeanEcliptic: {mars_ecliptic.distance.to('AU'):.8f}")
print(f"difference: {(mars_icrs.distance - mars_ecliptic.distance).to('km'):.3f}")