def to_arcmin(crosshair, origin, pixels_per_arcmin):
    """Convert the crosshair location from pixels to arcmin.

    Parameters
    ----------
    crosshair : :class:`dict`
        The location of the crosshair.
    origin : :class:`dict`
        The location of the origin.
    pixels_per_arcmin : :class:`float`
        The pixels/arcmin conversion factor.

    Returns
    -------
    :class:`dict`
        The coordinates of the crosshair, in arcmin units.
    """
    try:
        return {
            'x': (crosshair['x'] - origin['x']) / pixels_per_arcmin,
            'y': (origin['y'] - crosshair['y']) / pixels_per_arcmin,
        }
    except TypeError:
        return {'x': None, 'y': None}