Units

EL-PASO defines custom astropy units for unit conversion. This is useful for converting between different time formats, as tt2000 and posixtime.

Unit name	Description
el_paso.units.cdf_epoch	Time unit representing milliseconds since 0000-01-01.
el_paso.units.tt2000	Time unit representing nanoseconds since 2000-01-01.
el_paso.units.posixtime	Time unit representing seconds since 1970-01-01.
el_paso.units.datenum	Time unit representing days since 0000-01-01, as used in MATLAB.
el_paso.units.RE	Unit of distance representing Earth radii.

There are eqivalences enabled for all custom units, meaning that conversion works as simple as:

from astropy import units as u
import el_paso as ep

posixtime_q = u.Quantity(1362265200.0, ep.units.posixtime)
cdf_tt2000_q = posixtime_q.to(ep.units.cdf_tt2000)