*download sdss image*

def _download_sdss_image(
            self):
        """*download sdss image*
        """
        self.log.info('starting the ``_download_sdss_image`` method')

        opt = ""
        if self.grid:
            opt += "G"

        if self.label:
            opt += "L"

        if self.photocat:
            opt += "P"

        if self.speccat:
            opt += "S"

        if self.invertColors:
            opt += "I"

        if len(opt):
            opt = "opt=%(opt)s&" % locals()

        width = self.pixelWidth

        scale = (self.arcminWidth * 60.) / width

        converter = unit_conversion(
            log=self.log
        )
        ra = converter.ra_sexegesimal_to_decimal(
            ra=self.ra
        )
        dec = converter.dec_sexegesimal_to_decimal(
            dec=self.dec
        )
        url = """http://skyservice.pha.jhu.edu/DR12/ImgCutout/getjpeg.aspx?ra=%(ra)s&dec=%(dec)s&scale=%(scale)s&%(opt)sPhotoObjs=on&width=%(width)s&height=%(width)s""" % locals(
        )

        from fundamentals.download import multiobject_download
        localUrls = multiobject_download(
            urlList=[url],
            downloadDirectory=self.downloadDirectory,
            log=self.log,
            timeStamp=False,
            timeout=180,
            concurrentDownloads=10,
            resetFilename=[self.filename],
            credentials=False,  # { 'username' : "...", "password", "..." }
            longTime=True,
            indexFilenames=False
        )

        print url

        self.log.info('completed the ``_download_sdss_image`` method')
        return None