def spkcvo(target, et, outref, refloc, abcorr, obssta, obsepc, obsctr, obsref):
    """
    Return the state of a specified target relative to an "observer,"
    where the observer has constant velocity in a specified reference
    frame.  The observer's state is provided by the calling program
    rather than by loaded SPK files.

    http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/spkcvo_c.html

    :param target: Name of target ephemeris object.
    :type target: str
    :param et: Observation epoch.
    :type et: float
    :param outref: Reference frame of output state.
    :type outref: str
    :param refloc: Output reference frame evaluation locus.
    :type refloc: str
    :param abcorr: Aberration correction.
    :type abcorr: str
    :param obssta: Observer state relative to center of motion.
    :type obssta: 6-Element Array of floats
    :param obsepc: Epoch of observer state.
    :type obsepc: float
    :param obsctr: Center of motion of observer.
    :type obsctr: str
    :param obsref: Frame of observer state.
    :type obsref: str
    :return:
            State of target with respect to observer,
            One way light time between target and observer.
    :rtype: tuple
    """
    target = stypes.stringToCharP(target)
    et = ctypes.c_double(et)
    outref = stypes.stringToCharP(outref)
    refloc = stypes.stringToCharP(refloc)
    abcorr = stypes.stringToCharP(abcorr)
    obssta = stypes.toDoubleVector(obssta)
    obsepc = ctypes.c_double(obsepc)
    obsctr = stypes.stringToCharP(obsctr)
    obsref = stypes.stringToCharP(obsref)
    state = stypes.emptyDoubleVector(6)
    lt = ctypes.c_double()
    libspice.spkcvo_c(target, et, outref, refloc, abcorr, obssta, obsepc,
                      obsctr, obsref, state, ctypes.byref(lt))
    return stypes.cVectorToPython(state), lt.value
Return the state of a specified target relative to an "observer,"
    where the observer has constant velocity in a specified reference
    frame.  The observer's state is provided by the calling program
    rather than by loaded SPK files.

    http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/spkcvo_c.html

    :param target: Name of target ephemeris object.
    :type target: str
    :param et: Observation epoch.
    :type et: float
    :param outref: Reference frame of output state.
    :type outref: str
    :param refloc: Output reference frame evaluation locus.
    :type refloc: str
    :param abcorr: Aberration correction.
    :type abcorr: str
    :param obssta: Observer state relative to center of motion.
    :type obssta: 6-Element Array of floats
    :param obsepc: Epoch of observer state.
    :type obsepc: float
    :param obsctr: Center of motion of observer.
    :type obsctr: str
    :param obsref: Frame of observer state.
    :type obsref: str
    :return:
            State of target with respect to observer,
            One way light time between target and observer.
    :rtype: tuple