def jhk_to_rmag(jmag,hmag,kmag):
return convert_constants(jmag,hmag,kmag,<EOL>RJHK,<EOL>RJH, RJK, RHK,<EOL>RJ, RH, RK)<EOL>
Converts given J, H, Ks mags to an R magnitude value.

    Parameters
    ----------

    jmag,hmag,kmag : float
        2MASS J, H, Ks mags of the object.

    Returns
    -------

    float
        The converted R band magnitude.