Exemple #1
0
def main(args) :

    log=get_logger()

    log.info("read frame")
    # read frame
    frame = read_frame(args.infile)

    log.info("apply fiberflat")
    # read fiberflat
    fiberflat = read_fiberflat(args.fiberflat)

    # apply fiberflat
    apply_fiberflat(frame, fiberflat)

    log.info("subtract sky")
    # read sky
    skymodel=read_sky(args.sky)

    # subtract sky
    subtract_sky(frame, skymodel)

    log.info("compute flux calibration")

    # read models
    model_flux,model_wave,model_fibers=read_stdstar_models(args.models)

    # check that the model_fibers are actually standard stars
    fibermap = frame.fibermap
    model_fibers = model_fibers%500
    if np.any(fibermap['OBJTYPE'][model_fibers] != 'STD'):
        for i in model_fibers:
            log.error("inconsistency with spectrum %d, OBJTYPE='%s' in fibermap"%(i,fibermap["OBJTYPE"][i]))
        sys.exit(12)

    fluxcalib = compute_flux_calibration(frame, model_wave, model_flux)

    # QA
    if (args.qafile is not None):
        log.info("performing fluxcalib QA")
        # Load
        qaframe = load_qa_frame(args.qafile, frame, flavor=frame.meta['FLAVOR'])
        # Run
        #import pdb; pdb.set_trace()
        qaframe.run_qa('FLUXCALIB', (frame, fluxcalib))
        # Write
        if args.qafile is not None:
            write_qa_frame(args.qafile, qaframe)
            log.info("successfully wrote {:s}".format(args.qafile))
        # Figure(s)
        if args.qafig is not None:
            qa_plots.frame_fluxcalib(args.qafig, qaframe, frame, fluxcalib)

    # write result
    write_flux_calibration(args.outfile, fluxcalib, header=frame.meta)

    log.info("successfully wrote %s"%args.outfile)
Exemple #2
0
def main(args) :

    log=get_logger()

    cmd = ['desi_compute_fluxcalibration',]
    for key, value in args.__dict__.items():
        if value is not None:
            cmd += ['--'+key, str(value)]
    cmd = ' '.join(cmd)
    log.info(cmd)

    log.info("read frame")
    # read frame
    frame = read_frame(args.infile)

    log.info("apply fiberflat")
    # read fiberflat
    fiberflat = read_fiberflat(args.fiberflat)

    # apply fiberflat
    apply_fiberflat(frame, fiberflat)

    log.info("subtract sky")
    # read sky
    skymodel=read_sky(args.sky)

    # subtract sky
    subtract_sky(frame, skymodel)

    log.info("compute flux calibration")

    # read models
    model_flux,model_wave,model_fibers,model_metadata=read_stdstar_models(args.models)

    if args.chi2cut > 0 :
        ok = np.where(model_metadata["CHI2DOF"]<args.chi2cut)[0]
        if ok.size == 0 :
            log.error("chi2cut has discarded all stars")
            sys.exit(12)
        nstars=model_flux.shape[0]
        nbad=nstars-ok.size
        if nbad>0 :
            log.warning("discarding %d star(s) out of %d because of chi2cut"%(nbad,nstars))
            model_flux=model_flux[ok]
            model_fibers=model_fibers[ok]
            model_metadata=model_metadata[:][ok]
    
    if args.delta_color_cut > 0 :
        ok = np.where(np.abs(model_metadata["MODEL_G-R"]-model_metadata["DATA_G-R"])<args.delta_color_cut)[0]
        nstars=model_flux.shape[0]
        nbad=nstars-ok.size
        if nbad>0 :
            log.warning("discarding %d star(s) out of %d because |delta_color|>%f"%(nbad,nstars,args.delta_color_cut))
            model_flux=model_flux[ok]
            model_fibers=model_fibers[ok]
            model_metadata=model_metadata[:][ok]
    

    # automatically reject stars that ar chi2 outliers
    if args.chi2cut_nsig > 0 :
        mchi2=np.median(model_metadata["CHI2DOF"])
        rmschi2=np.std(model_metadata["CHI2DOF"])
        maxchi2=mchi2+args.chi2cut_nsig*rmschi2
        ok=np.where(model_metadata["CHI2DOF"]<=maxchi2)[0]
        nstars=model_flux.shape[0]
        nbad=nstars-ok.size
        if nbad>0 :
            log.warning("discarding %d star(s) out of %d because reduced chi2 outliers (at %d sigma, giving rchi2<%f )"%(nbad,nstars,args.chi2cut_nsig,maxchi2))
            model_flux=model_flux[ok]
            model_fibers=model_fibers[ok]
            model_metadata=model_metadata[:][ok]
    
    # check that the model_fibers are actually standard stars
    fibermap = frame.fibermap

    ## check whether star fibers from args.models are consistent with fibers from fibermap
    ## if not print the OBJTYPE from fibermap for the fibers numbers in args.models and exit
    fibermap_std_indices = np.where(isStdStar(fibermap['DESI_TARGET']))[0]
    if np.any(~np.in1d(model_fibers%500, fibermap_std_indices)):
        for i in model_fibers%500:
            log.error("inconsistency with spectrum {}, OBJTYPE='{}', DESI_TARGET={} in fibermap".format(
                (i, fibermap["OBJTYPE"][i], fibermap["DESI_TARGET"][i])))
        sys.exit(12)

    fluxcalib = compute_flux_calibration(frame, model_wave, model_flux, model_fibers%500)

    # QA
    if (args.qafile is not None):
        log.info("performing fluxcalib QA")
        # Load
        qaframe = load_qa_frame(args.qafile, frame, flavor=frame.meta['FLAVOR'])
        # Run
        #import pdb; pdb.set_trace()
        qaframe.run_qa('FLUXCALIB', (frame, fluxcalib))
        # Write
        if args.qafile is not None:
            write_qa_frame(args.qafile, qaframe)
            log.info("successfully wrote {:s}".format(args.qafile))
        # Figure(s)
        if args.qafig is not None:
            qa_plots.frame_fluxcalib(args.qafig, qaframe, frame, fluxcalib)

    # write result
    write_flux_calibration(args.outfile, fluxcalib, header=frame.meta)

    log.info("successfully wrote %s"%args.outfile)
def main(args):

    log = get_logger()

    log.info("read frame")
    # read frame
    frame = read_frame(args.infile)

    log.info("apply fiberflat")
    # read fiberflat
    fiberflat = read_fiberflat(args.fiberflat)

    # apply fiberflat
    apply_fiberflat(frame, fiberflat)

    log.info("subtract sky")
    # read sky
    skymodel = read_sky(args.sky)

    # subtract sky
    subtract_sky(frame, skymodel)

    log.info("compute flux calibration")

    # read models
    model_flux, model_wave, model_fibers = read_stdstar_models(args.models)
    model_tuple = model_flux, model_wave, model_fibers

    # check that the model_fibers are actually standard stars
    fibermap = frame.fibermap
    model_fibers = model_fibers % 500
    if np.any(fibermap['OBJTYPE'][model_fibers] != 'STD'):
        for i in model_fibers:
            log.error(
                "inconsistency with spectrum %d, OBJTYPE='%s' in fibermap" %
                (i, fibermap["OBJTYPE"][i]))
        sys.exit(12)

    #fluxcalib, indiv_stars = compute_flux_calibration(frame, model_wave, model_flux)
    fluxcalib = compute_flux_calibration(frame, model_wave, model_flux)

    # QA
    if (args.qafile is not None):
        log.info("performing fluxcalib QA")
        # Load
        qaframe = load_qa_frame(args.qafile,
                                frame,
                                flavor=frame.meta['FLAVOR'])
        # Run
        qaframe.run_qa('FLUXCALIB',
                       (frame, fluxcalib, model_tuple))  #, indiv_stars))
        # Write
        if args.qafile is not None:
            write_qa_frame(args.qafile, qaframe)
            log.info("successfully wrote {:s}".format(args.qafile))
        # Figure(s)
        if args.qafig is not None:
            qa_plots.frame_fluxcalib(args.qafig, qaframe, frame, fluxcalib,
                                     model_tuple)

    # write result
    write_flux_calibration(args.outfile, fluxcalib, header=frame.meta)

    log.info("successfully wrote %s" % args.outfile)
Exemple #4
0
def main(args):

    log = get_logger()

    cmd = [
        'desi_compute_fluxcalibration',
    ]
    for key, value in args.__dict__.items():
        if value is not None:
            cmd += ['--' + key, str(value)]
    cmd = ' '.join(cmd)
    log.info(cmd)

    log.info("read frame")
    # read frame
    frame = read_frame(args.infile)

    # Set fibermask flagged spectra to have 0 flux and variance
    frame = get_fiberbitmasked_frame(frame,
                                     bitmask='flux',
                                     ivar_framemask=True)

    log.info("apply fiberflat")
    # read fiberflat
    fiberflat = read_fiberflat(args.fiberflat)

    # apply fiberflat
    apply_fiberflat(frame, fiberflat)

    log.info("subtract sky")
    # read sky
    skymodel = read_sky(args.sky)

    # subtract sky
    subtract_sky(frame, skymodel)

    log.info("compute flux calibration")

    # read models
    model_flux, model_wave, model_fibers, model_metadata = read_stdstar_models(
        args.models)

    ok = np.ones(len(model_metadata), dtype=bool)

    if args.chi2cut > 0:
        log.info("Apply cut CHI2DOF<{}".format(args.chi2cut))
        ok &= (model_metadata["CHI2DOF"] < args.chi2cut)
    if args.delta_color_cut > 0:
        log.info("Apply cut |delta color|<{}".format(args.delta_color_cut))
        ok &= (np.abs(model_metadata["MODEL_G-R"] - model_metadata["DATA_G-R"])
               < args.delta_color_cut)
    if args.min_color is not None:
        log.info("Apply cut DATA_G-R>{}".format(args.min_color))
        ok &= (model_metadata["DATA_G-R"] > args.min_color)
    if args.chi2cut_nsig > 0:
        # automatically reject stars that ar chi2 outliers
        mchi2 = np.median(model_metadata["CHI2DOF"])
        rmschi2 = np.std(model_metadata["CHI2DOF"])
        maxchi2 = mchi2 + args.chi2cut_nsig * rmschi2
        log.info("Apply cut CHI2DOF<{} based on chi2cut_nsig={}".format(
            maxchi2, args.chi2cut_nsig))
        ok &= (model_metadata["CHI2DOF"] <= maxchi2)

    ok = np.where(ok)[0]
    if ok.size == 0:
        log.error("cuts discarded all stars")
        sys.exit(12)
    nstars = model_flux.shape[0]
    nbad = nstars - ok.size
    if nbad > 0:
        log.warning("discarding %d star(s) out of %d because of cuts" %
                    (nbad, nstars))
        model_flux = model_flux[ok]
        model_fibers = model_fibers[ok]
        model_metadata = model_metadata[:][ok]

    # check that the model_fibers are actually standard stars
    fibermap = frame.fibermap

    ## check whether star fibers from args.models are consistent with fibers from fibermap
    ## if not print the OBJTYPE from fibermap for the fibers numbers in args.models and exit
    fibermap_std_indices = np.where(isStdStar(fibermap))[0]
    if np.any(~np.in1d(model_fibers % 500, fibermap_std_indices)):
        target_colnames, target_masks, survey = main_cmx_or_sv(fibermap)
        colname = target_colnames[0]
        for i in model_fibers % 500:
            log.error(
                "inconsistency with spectrum {}, OBJTYPE={}, {}={} in fibermap"
                .format(i, fibermap["OBJTYPE"][i], colname,
                        fibermap[colname][i]))
        sys.exit(12)

    # Make sure the fibers of interest aren't entirely masked.
    if np.sum(
            np.sum(frame.ivar[model_fibers % 500, :] == 0, axis=1) ==
            frame.nwave) == len(model_fibers):
        log.warning('All standard-star spectra are masked!')
        return

    fluxcalib = compute_flux_calibration(
        frame,
        model_wave,
        model_flux,
        model_fibers % 500,
        highest_throughput_nstars=args.highest_throughput)

    # QA
    if (args.qafile is not None):
        log.info("performing fluxcalib QA")
        # Load
        qaframe = load_qa_frame(args.qafile,
                                frame_meta=frame.meta,
                                flavor=frame.meta['FLAVOR'])
        # Run
        #import pdb; pdb.set_trace()
        qaframe.run_qa('FLUXCALIB', (frame, fluxcalib))
        # Write
        if args.qafile is not None:
            write_qa_frame(args.qafile, qaframe)
            log.info("successfully wrote {:s}".format(args.qafile))
        # Figure(s)
        if args.qafig is not None:
            qa_plots.frame_fluxcalib(args.qafig, qaframe, frame, fluxcalib)

    # write result
    write_flux_calibration(args.outfile, fluxcalib, header=frame.meta)

    log.info("successfully wrote %s" % args.outfile)
Exemple #5
0
def main(args):

    log = get_logger()

    log.info("read frame")
    # read frame
    frame = read_frame(args.infile)

    log.info("apply fiberflat")
    # read fiberflat
    fiberflat = read_fiberflat(args.fiberflat)

    # apply fiberflat
    apply_fiberflat(frame, fiberflat)

    log.info("subtract sky")
    # read sky
    skymodel = read_sky(args.sky)

    # subtract sky
    subtract_sky(frame, skymodel)

    log.info("compute flux calibration")

    # read models
    model_flux, model_wave, model_fibers, model_metadata = read_stdstar_models(
        args.models)

    if args.chi2cut > 0:
        ok = np.where(model_metadata["CHI2DOF"] < args.chi2cut)[0]
        if ok.size == 0:
            log.error("chi2cut has discarded all stars")
            sys.exit(12)
        nstars = model_flux.shape[0]
        nbad = nstars - ok.size
        if nbad > 0:
            log.warning("discarding %d star(s) out of %d because of chi2cut" %
                        (nbad, nstars))
            model_flux = model_flux[ok]
            model_fibers = model_fibers[ok]
            model_metadata = model_metadata[:][ok]

    if args.delta_color_cut > 0:
        ok = np.where(
            np.abs(model_metadata["MODEL_G-R"] -
                   model_metadata["DATA_G-R"]) < args.delta_color_cut)[0]
        nstars = model_flux.shape[0]
        nbad = nstars - ok.size
        if nbad > 0:
            log.warning(
                "discarding %d star(s) out of %d because |delta_color|>%f" %
                (nbad, nstars, args.delta_color_cut))
            model_flux = model_flux[ok]
            model_fibers = model_fibers[ok]
            model_metadata = model_metadata[:][ok]

    # automatically reject stars that ar chi2 outliers
    if args.chi2cut_nsig > 0:
        mchi2 = np.median(model_metadata["CHI2DOF"])
        rmschi2 = np.std(model_metadata["CHI2DOF"])
        maxchi2 = mchi2 + args.chi2cut_nsig * rmschi2
        ok = np.where(model_metadata["CHI2DOF"] <= maxchi2)[0]
        nstars = model_flux.shape[0]
        nbad = nstars - ok.size
        if nbad > 0:
            log.warning(
                "discarding %d star(s) out of %d because reduced chi2 outliers (at %d sigma, giving rchi2<%f )"
                % (nbad, nstars, args.chi2cut_nsig, maxchi2))
            model_flux = model_flux[ok]
            model_fibers = model_fibers[ok]
            model_metadata = model_metadata[:][ok]

    # check that the model_fibers are actually standard stars
    fibermap = frame.fibermap

    ## check whether star fibers from args.models are consistent with fibers from fibermap
    ## if not print the OBJTYPE from fibermap for the fibers numbers in args.models and exit
    w = np.where(fibermap["OBJTYPE"][model_fibers % 500] != 'STD')[0]

    if len(w) > 0:
        for i in model_fibers % 500:
            log.error(
                "inconsistency with spectrum %d, OBJTYPE='%s' in fibermap" %
                (i, fibermap["OBJTYPE"][i]))
        sys.exit(12)

    fluxcalib = compute_flux_calibration(frame, model_wave, model_flux,
                                         model_fibers % 500)

    # QA
    if (args.qafile is not None):
        log.info("performing fluxcalib QA")
        # Load
        qaframe = load_qa_frame(args.qafile,
                                frame,
                                flavor=frame.meta['FLAVOR'])
        # Run
        #import pdb; pdb.set_trace()
        qaframe.run_qa('FLUXCALIB', (frame, fluxcalib))
        # Write
        if args.qafile is not None:
            write_qa_frame(args.qafile, qaframe)
            log.info("successfully wrote {:s}".format(args.qafile))
        # Figure(s)
        if args.qafig is not None:
            qa_plots.frame_fluxcalib(args.qafig, qaframe, frame, fluxcalib)

    # write result
    write_flux_calibration(args.outfile, fluxcalib, header=frame.meta)

    log.info("successfully wrote %s" % args.outfile)
Exemple #6
0
def main(args):

    log = get_logger()

    cmd = [
        'desi_compute_fluxcalibration',
    ]
    for key, value in args.__dict__.items():
        if value is not None:
            cmd += ['--' + key, str(value)]
    cmd = ' '.join(cmd)
    log.info(cmd)

    log.info("read frame")
    # read frame
    frame = read_frame(args.infile)

    # Set fibermask flagged spectra to have 0 flux and variance
    frame = get_fiberbitmasked_frame(frame,
                                     bitmask='flux',
                                     ivar_framemask=True)

    log.info("apply fiberflat")
    # read fiberflat
    fiberflat = read_fiberflat(args.fiberflat)

    # apply fiberflat
    apply_fiberflat(frame, fiberflat)

    log.info("subtract sky")
    # read sky
    skymodel = read_sky(args.sky)

    # subtract sky
    subtract_sky(frame, skymodel)

    log.info("compute flux calibration")

    # read models
    model_flux, model_wave, model_fibers, model_metadata = read_stdstar_models(
        args.models)

    ok = np.ones(len(model_metadata), dtype=bool)

    if args.chi2cut > 0:
        log.info("apply cut CHI2DOF<{}".format(args.chi2cut))
        good = (model_metadata["CHI2DOF"] < args.chi2cut)
        bad = ~good
        ok &= good
        if np.any(bad):
            log.info(" discard {} stars with CHI2DOF= {}".format(
                np.sum(bad), list(model_metadata["CHI2DOF"][bad])))

    legacy_filters = ('G-R', 'R-Z')
    gaia_filters = ('GAIA-BP-RP', 'GAIA-G-RP')
    model_column_list = model_metadata.columns.names
    if args.color is None:
        if 'MODEL_G-R' in model_column_list:
            color = 'G-R'
        elif 'MODEL_GAIA-BP-RP' in model_column_list:
            log.info('Using Gaia filters')
            color = 'GAIA-BP-RP'
        else:
            log.error(
                "Can't find either G-R or BP-RP color in the model file.")
            sys.exit(15)
    else:
        if args.color not in legacy_filters and args.color not in gaia_filters:
            log.error(
                'Color name {} is not allowed, must be one of {} {}'.format(
                    args.color, legacy_filters, gaia_filters))
            sys.exit(14)
        color = args.color
        if color not in model_column_list:
            # This should't happen
            log.error(
                'The color {} was not computed in the models'.format(color))
            sys.exit(16)

    if args.delta_color_cut > 0:
        log.info("apply cut |delta color|<{}".format(args.delta_color_cut))
        good = (np.abs(model_metadata["MODEL_" + color] -
                       model_metadata["DATA_" + color]) < args.delta_color_cut)
        bad = ok & (~good)
        ok &= good
        if np.any(bad):
            vals = model_metadata["MODEL_" +
                                  color][bad] - model_metadata["DATA_" +
                                                               color][bad]
            log.info(" discard {} stars with dcolor= {}".format(
                np.sum(bad), list(vals)))

    if args.min_color is not None:
        log.info("apply cut DATA_{}>{}".format(color, args.min_color))
        good = (model_metadata["DATA_{}".format(color)] > args.min_color)
        bad = ok & (~good)
        ok &= good
        if np.any(bad):
            vals = model_metadata["DATA_{}".format(color)][bad]
            log.info(" discard {} stars with {}= {}".format(
                np.sum(bad), color, list(vals)))

    if args.chi2cut_nsig > 0:
        # automatically reject stars that ar chi2 outliers
        mchi2 = np.median(model_metadata["CHI2DOF"])
        rmschi2 = np.std(model_metadata["CHI2DOF"])
        maxchi2 = mchi2 + args.chi2cut_nsig * rmschi2
        log.info("apply cut CHI2DOF<{} based on chi2cut_nsig={}".format(
            maxchi2, args.chi2cut_nsig))
        good = (model_metadata["CHI2DOF"] <= maxchi2)
        bad = ok & (~good)
        ok &= good
        if np.any(bad):
            log.info(" discard {} stars with CHI2DOF={}".format(
                np.sum(bad), list(model_metadata["CHI2DOF"][bad])))

    ok = np.where(ok)[0]
    if ok.size == 0:
        log.error("selection cuts discarded all stars")
        sys.exit(12)
    nstars = model_flux.shape[0]
    nbad = nstars - ok.size
    if nbad > 0:
        log.warning("discarding %d star(s) out of %d because of cuts" %
                    (nbad, nstars))
        model_flux = model_flux[ok]
        model_fibers = model_fibers[ok]
        model_metadata = model_metadata[:][ok]

    # check that the model_fibers are actually standard stars
    fibermap = frame.fibermap

    ## check whether star fibers from args.models are consistent with fibers from fibermap
    ## if not print the OBJTYPE from fibermap for the fibers numbers in args.models and exit
    fibermap_std_indices = np.where(isStdStar(fibermap))[0]
    if np.any(~np.in1d(model_fibers % 500, fibermap_std_indices)):
        target_colnames, target_masks, survey = main_cmx_or_sv(fibermap)
        colname = target_colnames[0]
        for i in model_fibers % 500:
            log.error(
                "inconsistency with spectrum {}, OBJTYPE={}, {}={} in fibermap"
                .format(i, fibermap["OBJTYPE"][i], colname,
                        fibermap[colname][i]))
        sys.exit(12)

    # Make sure the fibers of interest aren't entirely masked.
    if np.sum(
            np.sum(frame.ivar[model_fibers % 500, :] == 0, axis=1) ==
            frame.nwave) == len(model_fibers):
        log.warning('All standard-star spectra are masked!')
        return

    fluxcalib = compute_flux_calibration(
        frame,
        model_wave,
        model_flux,
        model_fibers % 500,
        highest_throughput_nstars=args.highest_throughput,
        exposure_seeing_fwhm=args.seeing_fwhm)

    # QA
    if (args.qafile is not None):

        from desispec.io import write_qa_frame
        from desispec.io.qa import load_qa_frame
        from desispec.qa import qa_plots

        log.info("performing fluxcalib QA")
        # Load
        qaframe = load_qa_frame(args.qafile,
                                frame_meta=frame.meta,
                                flavor=frame.meta['FLAVOR'])
        # Run
        #import pdb; pdb.set_trace()
        qaframe.run_qa('FLUXCALIB', (frame, fluxcalib))
        # Write
        if args.qafile is not None:
            write_qa_frame(args.qafile, qaframe)
            log.info("successfully wrote {:s}".format(args.qafile))
        # Figure(s)
        if args.qafig is not None:
            qa_plots.frame_fluxcalib(args.qafig, qaframe, frame, fluxcalib)

    # record inputs
    frame.meta['IN_FRAME'] = shorten_filename(args.infile)
    frame.meta['IN_SKY'] = shorten_filename(args.sky)
    frame.meta['FIBERFLT'] = shorten_filename(args.fiberflat)
    frame.meta['STDMODEL'] = shorten_filename(args.models)

    # write result
    write_flux_calibration(args.outfile, fluxcalib, header=frame.meta)

    log.info("successfully wrote %s" % args.outfile)
def main() :

    parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)

    parser.add_argument('--infile', type = str, default = None, required=True,
                        help = 'path of DESI exposure frame fits file')
    parser.add_argument('--fibermap', type = str, default = None, required=True,
                        help = 'path of DESI exposure frame fits file')
    parser.add_argument('--fiberflat', type = str, default = None, required=True,
                        help = 'path of DESI fiberflat fits file')
    parser.add_argument('--sky', type = str, default = None, required=True,
                        help = 'path of DESI sky fits file')
    parser.add_argument('--models', type = str, default = None, required=True,
                        help = 'path of spetro-photometric stellar spectra fits file')
    parser.add_argument('--outfile', type = str, default = None, required=True,
                        help = 'path of DESI flux calbration fits file')


    args = parser.parse_args()
    log=get_logger()

    log.info("read frame")
    # read frame
    frame = read_frame(args.infile)

    log.info("apply fiberflat")
    # read fiberflat
    fiberflat = read_fiberflat(args.fiberflat)

    # apply fiberflat
    apply_fiberflat(frame, fiberflat)
    
    log.info("subtract sky")
    # read sky
    skymodel=read_sky(args.sky)

    # subtract sky
    subtract_sky(frame, skymodel)

    log.info("compute flux calibration")

    # read models
    model_flux,model_wave,model_fibers=read_stdstar_models(args.models)

    # select fibers
    SPECMIN=frame.header["SPECMIN"]
    SPECMAX=frame.header["SPECMAX"]
    selec=np.where((model_fibers>=SPECMIN)&(model_fibers<=SPECMAX))[0]
    if selec.size == 0 :
        log.error("no stellar models for this spectro")
        sys.exit(12)
    fibers=model_fibers[selec]-frame.header["SPECMIN"]
    log.info("star fibers= %s"%str(fibers))

    table = read_fibermap(args.fibermap)
    bad=np.where(table["OBJTYPE"][fibers]!="STD")[0]
    if bad.size > 0 :
        for fiber in fibers[bad] :
            log.error("inconsistency with fiber %d, OBJTYPE='%s' in fibermap"%(fiber,table["OBJTYPE"][fiber]))
        sys.exit(12)

    fluxcalib = compute_flux_calibration(frame, fibers, model_wave, model_flux)

    # write result
    write_flux_calibration(args.outfile, fluxcalib, header=frame.header)


    log.info("successfully wrote %s"%args.outfile)