Plot a finder chart. This *does* create a new figure.

def finder(self, figsize=(7,7), **kwargs):
        '''
        Plot a finder chart. This *does* create a new figure.
        '''

        try:
            center = self.meta['center']
            radius = self.meta['radius']
        except KeyError:
            return self.allskyfinder(**kwargs)

        plt.figure(figsize=figsize)
        scatter = self.plot(**kwargs)
        plt.xlabel(r'Right Ascension ($^\circ$)'); plt.ylabel(r'Declination ($^\circ$)')
        #plt.title('{} in {:.1f}'.format(self.name, epoch))
        r = radius.to('deg').value
        plt.xlim(center.ra.deg + r/np.cos(center.dec), center.ra.deg - r/np.cos(center.dec))
        plt.ylim(center.dec.deg - r, center.dec.deg + r)
        ax = plt.gca()
        ax.set_aspect(1.0/np.cos(center.dec))

        return scatter