Barycentric Julian Date
This online applet will convert a list of UTCs to a list of
Barycentric Julian Dates in Barycentric Dynamical Time (BJD_TDB) to an
accuracy of 20 ms, or the accuracy of double precision (~few ms) if
the observatory is given. A brief, non-technical explanation of
BJD_TDB can be found here. Mouse
over or click the input headings for additional information.
There is a programmatic interface to this applet.
is an example that converts a list of JD_UTCs to BJD_TDB for alpha
Centauri. The RA and Dec are always in decimal hours and the FUNCTION
can be utc2bjd, bjd2utc or hjd2bjd. It does not support any
observatories, so is only accurate to 20 ms.