def et2jd(et):
import spiceypy as sp
# Convert et to jed
jed=sp.unitim(et,"ET","JED")
# Calculate the deltat at et
deltat=sp.deltet(et,"ET");
# Add deltat to et
jd=jed-deltat/86400.0
return jd
def jd2et(jd):
import spiceypy as sp
# Convert from JD to UTC seconds (seconds since J2000)
utc=(jd-sp.j2000())/365.25*sp.jyear()
# Compute deltat = ET - UTC
deltat=sp.deltet(utc,"UTC");
# Compute ET
et=utc+deltat
return et
