08. JDUTC to BJDTDB converter

As explained in Eastman et al. 2010, we also include a JDUTC to BJDTDB time converter.

We include the following corrections -

1. Clock Correction - To correct for difference between UTC and TDB time scales.
2. Geometric Correction - Light travel time from observatory to Solar System Barycenter.
3. Einstein Correction - Relativistic correction since Earth is not an inertial frame.

The output of our function - utc_tdb.JDUTC_to_BJDTDB() matches the web applet converter to about 0.2ms . Therefore for applications requiring higher precision it should not be used.

To run this standalone still requires downloading the barycorrpy package since the function requires the leap second time converter, Hipparcos catalog and the PINT routine to calculate the Earth Orientation Parameters. These are included in the package.

An example to run this function is shown below -

>>> from astropy.time import Time
>>> from barycorrpy import utc_tdb
>>> JDUTC = Time(2458000, format='jd', scale='utc')
>>> utc_tdb.JDUTC_to_BJDTDB(JDUTC,hip_id=8102, lat=-30.169283, longi=-70.806789, alt=2241.9)
(array([ 2458000.00505211]), [[], []], 0)