I am trying to use get_body()
to get position and motion data for solar system objects.
I’ve tried the following:
from astropy.time import Time
from astropy.coordinates import solar_system_ephemeris, get_body
t = Time('2019.5',format='jyear')
mars = get_body('Mars',t,ephemeris='de432s')
print(mars.ra)
print(mars.dec)
print(mars.pm_dec)
The first two print statements work fine. The last line throws this error:
TypeError: Frame data has no associated differentials (i.e. the frame has no velocity data) - represent_as() only accepts a new representation.
The same thing happens if I try any other solar system body as well.
Can I get motion data (such as the rate of change of the declination) using get_body()
?