Source code for pypeit.spectrographs.keck_hires

"""
Module for Keck/HIRES

.. include:: ../include/links.rst
"""
import os

from IPython import embed



import numpy as np
from scipy.io import readsav

from astropy.table import Table

from pypeit import msgs
from pypeit import telescopes
from pypeit import io
from pypeit.core import parse
from pypeit.core import framematch
from pypeit.spectrographs import spectrograph
from pypeit.images import detector_container
from pypeit.par import pypeitpar
from pypeit.images.mosaic import Mosaic
from pypeit.core.mosaic import build_image_mosaic_transform


[docs]class HIRESMosaicLookUp: """ Provides the geometry required to mosaic Keck HIRES data. Similar to :class:`~pypeit.spectrographs.gemini_gmos.GeminiGMOSMosaicLookUp` """ # Original geometry = { 'MSC01': {'default_shape': (6168, 3990), 'blue_det': {'shift': (-2048.0 - 41.0, -3.), 'rotation': 0.}, 'green_det': {'shift': (0., 0.), 'rotation': 0.}, 'red_det': {'shift': (2048.0 + 53.0, 0.), 'rotation': 0.}}, }
# adding -3 to the blue_det shift in the y-direction helps to deal with the gap # in the 2D fit wavelength solution between the blue and green detectors
[docs]class KECKHIRESSpectrograph(spectrograph.Spectrograph): """ Child to handle KECK/HIRES specific code. This spectrograph is not yet supported. """ ndet = 3 name = 'keck_hires' telescope = telescopes.KeckTelescopePar() camera = 'HIRES' url = 'https://www2.keck.hawaii.edu/inst/hires/' header_name = 'HIRES' url = 'https://www2.keck.hawaii.edu/inst/hires/' pypeline = 'Echelle' ech_fixed_format = False supported = False # TODO before support = True # 1. Implement flat fielding # 2. Test on several different setups # 3. Implement PCA extrapolation into the blue # TODO: Place holder parameter set taken from X-shooter VIS for now.
[docs] @classmethod def default_pypeit_par(cls): """ Return the default parameters to use for this instrument. Returns: :class:`~pypeit.par.pypeitpar.PypeItPar`: Parameters required by all of PypeIt methods. """ par = super().default_pypeit_par() par['rdx']['detnum'] = [(1,2,3)] # Adjustments to parameters for Keck HIRES turn_on = dict(use_biasimage=False, use_overscan=True, overscan_method='median', use_darkimage=False, use_illumflat=False, use_pixelflat=False, use_specillum=False) par.reset_all_processimages_par(**turn_on) par['calibrations']['traceframe']['process']['overscan_method'] = 'median' # Right now we are using the overscan and not biases becuase the # standards are read with a different read mode and we don't yet have # the option to use different sets of biases for different standards, # or use the overscan for standards but not for science frames # TODO testing par['scienceframe']['process']['use_biasimage'] = False par['scienceframe']['process']['use_illumflat'] = False par['scienceframe']['process']['use_pixelflat'] = False par['calibrations']['standardframe']['process']['use_illumflat'] = False par['calibrations']['standardframe']['process']['use_pixelflat'] = False # par['scienceframe']['useframe'] ='overscan' par['calibrations']['slitedges']['edge_thresh'] = 8.0 par['calibrations']['slitedges']['fit_order'] = 8 par['calibrations']['slitedges']['max_shift_adj'] = 0.5 par['calibrations']['slitedges']['trace_thresh'] = 10. par['calibrations']['slitedges']['left_right_pca'] = True par['calibrations']['slitedges']['length_range'] = 0.3 par['calibrations']['slitedges']['max_nudge'] = 0. par['calibrations']['slitedges']['overlap'] = True par['calibrations']['slitedges']['dlength_range'] = 0.25 par['calibrations']['slitedges']['add_missed_orders'] = True par['calibrations']['slitedges']['order_width_poly'] = 2 par['calibrations']['slitedges']['order_gap_poly'] = 3 # These are the defaults par['calibrations']['tilts']['tracethresh'] = 15 par['calibrations']['tilts']['spat_order'] = 3 par['calibrations']['tilts']['spec_order'] = 5 # [5, 5, 5] + 12*[7] # + [5] # 1D wavelength solution par['calibrations']['wavelengths']['lamps'] = ['ThAr'] par['calibrations']['wavelengths']['rms_thresh_frac_fwhm'] = 0.1 par['calibrations']['wavelengths']['sigdetect'] = 5. par['calibrations']['wavelengths']['n_first'] = 3 par['calibrations']['wavelengths']['n_final'] = 4 par['calibrations']['wavelengths']['match_toler'] = 1.5 # Reidentification parameters par['calibrations']['wavelengths']['method'] = 'echelle' par['calibrations']['wavelengths']['cc_shift_range'] = (-80.,80.) par['calibrations']['wavelengths']['cc_thresh'] = 0.6 par['calibrations']['wavelengths']['cc_local_thresh'] = 0.25 par['calibrations']['wavelengths']['reid_cont_sub'] = False # Echelle parameters par['calibrations']['wavelengths']['echelle'] = True par['calibrations']['wavelengths']['ech_nspec_coeff'] = 5 par['calibrations']['wavelengths']['ech_norder_coeff'] = 3 par['calibrations']['wavelengths']['ech_sigrej'] = 2.0 par['calibrations']['wavelengths']['ech_separate_2d'] = True par['calibrations']['wavelengths']['bad_orders_maxfrac'] = 0.5 # Flats par['calibrations']['flatfield']['tweak_slits_thresh'] = 0.90 par['calibrations']['flatfield']['tweak_slits_maxfrac'] = 0.10 # Extraction par['reduce']['skysub']['bspline_spacing'] = 0.6 par['reduce']['skysub']['global_sky_std'] = False # local sky subtraction operates on entire slit par['reduce']['extraction']['model_full_slit'] = True # Mask 3 edges pixels since the slit is short, insted of default (5,5) par['reduce']['findobj']['find_trim_edge'] = [3, 3] # Continnum order for determining thresholds # Sensitivity function parameters par['sensfunc']['algorithm'] = 'IR' par['sensfunc']['polyorder'] = 5 #[9, 11, 11, 9, 9, 8, 8, 7, 7, 7, 7, 7, 7, 7, 7] par['sensfunc']['IR']['telgridfile'] = 'TellPCA_3000_10500_R120000.fits' par['sensfunc']['IR']['pix_shift_bounds'] = (-40.0,40.0) # Telluric parameters # HIRES is usually oversampled, so the helio shift can be large par['telluric']['pix_shift_bounds'] = (-40.0,40.0) # Similarly, the resolution guess is higher than it should be par['telluric']['resln_frac_bounds'] = (0.25,1.25) # Coadding par['coadd1d']['wave_method'] = 'log10' return par
[docs] def config_specific_par(self, scifile, inp_par=None): """ Modify the PypeIt parameters to hard-wired values used for specific instrument configurations. Args: scifile (:obj:`str`): File to use when determining the configuration and how to adjust the input parameters. inp_par (:class:`~pypeit.par.parset.ParSet`, optional): Parameter set used for the full run of PypeIt. If None, use :func:`default_pypeit_par`. Returns: :class:`~pypeit.par.parset.ParSet`: The PypeIt parameter set adjusted for configuration specific parameter values. """ par = super().config_specific_par(scifile, inp_par=inp_par) headarr = self.get_headarr(scifile) bin_spec, bin_spat = parse.parse_binning(self.get_meta_value(headarr, 'binning')) # slit edges # NOTE: With add_missed_orders set to True and order_spat_range set to the # default (None), the code will try to add missing orders over the full # range of the detector mosaic! par['calibrations']['slitedges']['order_spat_range'] = [10., 6200./bin_spat] # wavelength par['calibrations']['wavelengths']['fwhm'] = 8.0/bin_spec # Return return par
[docs] def init_meta(self): """ Define how metadata are derived from the spectrograph files. That is, this associates the PypeIt-specific metadata keywords with the instrument-specific header cards using :attr:`meta`. """ self.meta = {} # Required (core) self.meta['ra'] = dict(ext=0, card='RA', required_ftypes=['science', 'standard']) self.meta['dec'] = dict(ext=0, card='DEC', required_ftypes=['science', 'standard']) self.meta['target'] = dict(ext=0, card='OBJECT') self.meta['decker'] = dict(ext=0, card='DECKNAME') self.meta['binning'] = dict(card=None, compound=True) self.meta['mjd'] = dict(ext=0, card='MJD') # This may depend on the old/new detector self.meta['exptime'] = dict(ext=0, card='ELAPTIME') self.meta['airmass'] = dict(ext=0, card='AIRMASS') #self.meta['dispname'] = dict(ext=0, card='ECHNAME') # Extras for config and frametyping self.meta['hatch'] = dict(ext=0, card='HATOPEN') self.meta['dispname'] = dict(ext=0, card='XDISPERS') self.meta['filter1'] = dict(ext=0, card='FIL1NAME') self.meta['echangle'] = dict(ext=0, card='ECHANGL', rtol=1e-3) self.meta['xdangle'] = dict(ext=0, card='XDANGL', rtol=1e-2) # self.meta['idname'] = dict(ext=0, card='IMAGETYP') # NOTE: This is the native keyword. IMAGETYP is from KOA. self.meta['idname'] = dict(ext=0, card='OBSTYPE') self.meta['frameno'] = dict(ext=0, card='FRAMENO') self.meta['instrument'] = dict(ext=0, card='INSTRUME')
[docs] def compound_meta(self, headarr, meta_key): """ Methods to generate metadata requiring interpretation of the header data, instead of simply reading the value of a header card. Args: headarr (:obj:`list`): List of `astropy.io.fits.Header`_ objects. meta_key (:obj:`str`): Metadata keyword to construct. Returns: object: Metadata value read from the header(s). """ if meta_key == 'binning': # TODO JFH Is this correct or should it be flipped? binspatial, binspec = parse.parse_binning(headarr[0]['BINNING']) binning = parse.binning2string(binspec, binspatial) return binning else: msgs.error("Not ready for this compound meta")
[docs] def configuration_keys(self): """ Return the metadata keys that define a unique instrument configuration. This list is used by :class:`~pypeit.metadata.PypeItMetaData` to identify the unique configurations among the list of frames read for a given reduction. Returns: :obj:`list`: List of keywords of data pulled from file headers and used to constuct the :class:`~pypeit.metadata.PypeItMetaData` object. """ return ['filter1', 'echangle', 'xdangle', 'binning']
[docs] def raw_header_cards(self): """ Return additional raw header cards to be propagated in downstream output files for configuration identification. The list of raw data FITS keywords should be those used to populate the :meth:`~pypeit.spectrographs.spectrograph.Spectrograph.configuration_keys` or are used in :meth:`~pypeit.spectrographs.spectrograph.Spectrograph.config_specific_par` for a particular spectrograph, if different from the name of the PypeIt metadata keyword. This list is used by :meth:`~pypeit.spectrographs.spectrograph.Spectrograph.subheader_for_spec` to include additional FITS keywords in downstream output files. Returns: :obj:`list`: List of keywords from the raw data files that should be propagated in output files. """ return ['FIL1NAME', 'ECHANGL', 'XDANGL']
[docs] def pypeit_file_keys(self): """ Define the list of keys to be output into a standard PypeIt file. Returns: :obj:`list`: The list of keywords in the relevant :class:`~pypeit.metadata.PypeItMetaData` instance to print to the :ref:`pypeit_file`. """ return super().pypeit_file_keys() + ['frameno']
[docs] def check_frame_type(self, ftype, fitstbl, exprng=None): """ Check for frames of the provided type. Args: ftype (:obj:`str`): Type of frame to check. Must be a valid frame type; see frame-type :ref:`frame_type_defs`. fitstbl (`astropy.table.Table`_): The table with the metadata for one or more frames to check. exprng (:obj:`list`, optional): Range in the allowed exposure time for a frame of type ``ftype``. See :func:`pypeit.core.framematch.check_frame_exptime`. Returns: `numpy.ndarray`_: Boolean array with the flags selecting the exposures in ``fitstbl`` that are ``ftype`` type frames. """ good_exp = framematch.check_frame_exptime(fitstbl['exptime'], exprng) # TODO: Allow for 'sky' frame type, for now include sky in # 'science' category if ftype == 'science': return good_exp & (fitstbl['idname'] == 'Object') if ftype == 'standard': return good_exp & (fitstbl['idname'] == 'Object') if ftype == 'bias': return good_exp & (fitstbl['idname'] == 'Bias') if ftype == 'dark': return good_exp & (fitstbl['idname'] == 'Dark') if ftype in ['pixelflat', 'trace']: # Flats and trace frames are typed together return good_exp & (fitstbl['idname'] == 'IntFlat') if ftype in ['arc', 'tilt']: # Arc and tilt frames are typed together return good_exp & (fitstbl['idname'] == 'Line') msgs.warn('Cannot determine if frames are of type {0}.'.format(ftype)) return np.zeros(len(fitstbl), dtype=bool)
[docs] def get_rawimage(self, raw_file, det, spectrim=20): """ Read raw images and generate a few other bits and pieces that are key for image processing. Based on readmhdufits.pro Parameters ---------- raw_file : :obj:`str` File to read det : :obj:`int` 1-indexed detector to read Returns ------- detector_par : :class:`pypeit.images.detector_container.DetectorContainer` Detector metadata parameters. raw_img : `numpy.ndarray`_ Raw image for this detector. hdu : `astropy.io.fits.HDUList`_ Opened fits file exptime : :obj:`float` Exposure time read from the file header rawdatasec_img : `numpy.ndarray`_ Data (Science) section of the detector as provided by setting the (1-indexed) number of the amplifier used to read each detector pixel. Pixels unassociated with any amplifier are set to 0. oscansec_img : `numpy.ndarray`_ Overscan section of the detector as provided by setting the (1-indexed) number of the amplifier used to read each detector pixel. Pixels unassociated with any amplifier are set to 0. """ # TODO -- Put a check in here to avoid data using the # original CCD (1 chip) # Check for file; allow for extra .gz, etc. suffix if not os.path.isfile(raw_file): msgs.error(f'{raw_file} not found!') hdu = io.fits_open(raw_file) head0 = hdu[0].header # Get post, pre-pix values precol = head0['PRECOL'] postpix = head0['POSTPIX'] preline = head0['PRELINE'] postline = head0['POSTLINE'] detlsize = head0['DETLSIZE'] x0, x_npix, y0, y_npix = np.array(parse.load_sections(detlsize)).flatten() # get the x and y binning factors... #binning = head0['BINNING'] binning = self.get_meta_value(self.get_headarr(hdu), 'binning') # # TODO: JFH I think this works fine # if binning != '3,1': # msgs.warn("This binning for HIRES might not work. But it might..") # We are flipping this because HIRES stores the binning oppostire of the (binspec, binspat) pypeit convention. binspatial, binspec = parse.parse_binning(head0['BINNING']) # Validate the entered (list of) detector(s) nimg, _det = self.validate_det(det) # Grab the detector or mosaic parameters mosaic = None if nimg == 1 else self.get_mosaic_par(det, hdu=hdu) detectors = [self.get_detector_par(det, hdu=hdu)] if nimg == 1 else mosaic.detectors # get the chips to read in # DP: I don't know if this needs to still exist. I believe det is never None if det is None: chips = range(self.ndet) else: chips = [d-1 for d in _det] # Indexing starts at 0 here # get final datasec and oscan size (it's the same for every chip so # it's safe to determine it outsize the loop) # Create final image if det is None: # JFH: TODO is this a good idea? image = np.zeros((x_npix, y_npix + 4 * postpix)) rawdatasec_img = np.zeros_like(image, dtype=int) oscansec_img = np.zeros_like(image, dtype=int) else: data, oscan = hires_read_1chip(hdu, chips[0] + 1) image = np.zeros((nimg, data.shape[0], data.shape[1] + oscan.shape[1])) rawdatasec_img = np.zeros_like(image, dtype=int) oscansec_img = np.zeros_like(image, dtype=int) # Loop over the chips for ii, tt in enumerate(chips): image_ii, oscan_ii = hires_read_1chip(hdu, tt + 1) # Indexing x1, x2, y1, y2, o_x1, o_x2, o_y1, o_y2 = indexing(tt, postpix, det=det, xbin=binspatial, ybin=binspec) # Fill image[ii, y1:y2, x1:x2] = image_ii image[ii, o_y1:o_y2, o_x1:o_x2] = oscan_ii rawdatasec_img[ii, y1:y2-spectrim//binspec, x1:x2] = 1 # Amp oscansec_img[ii, o_y1:o_y2-spectrim//binspec, o_x1:o_x2] = 1 # Amp exptime = hdu[self.meta['exptime']['ext']].header[self.meta['exptime']['card']] # Return # Handle returning both single and multiple images if nimg == 1: return detectors[0], image[0], hdu, exptime, rawdatasec_img[0], oscansec_img[0] return mosaic, image, hdu, exptime, rawdatasec_img, oscansec_img
[docs] def get_mosaic_par(self, mosaic, hdu=None, msc_order=0): """ Return the hard-coded parameters needed to construct detector mosaics from unbinned images. The parameters expect the images to be trimmed and oriented to follow the PypeIt shape convention of ``(nspec,nspat)``. For returned lists, the length of the list is the same as the number of detectors in the mosaic, and they are ordered by the detector number. Args: mosaic (:obj:`tuple`): Tuple of detector numbers used to construct the mosaic. Must be one among the list of possible mosaics as hard-coded by the :func:`allowed_mosaics` function. hdu (`astropy.io.fits.HDUList`_, optional): The open fits file with the raw image of interest. If not provided, frame-dependent detector parameters are set to a default. BEWARE: If ``hdu`` is not provided, the binning is assumed to be `1,1`, which will cause faults if applied to binned images! msc_order (:obj:`int`, optional): Order of the interpolation used to construct the mosaic. Returns: :class:`~pypeit.images.mosaic.Mosaic`: Object with the mosaic *and* detector parameters. """ # Validate the entered (list of) detector(s) nimg, _ = self.validate_det(mosaic) # Index of mosaic in list of allowed detector combinations mosaic_id = self.allowed_mosaics.index(mosaic)+1 detid = f'MSC0{mosaic_id}' # Get the detectors detectors = np.array([self.get_detector_par(det, hdu=hdu) for det in mosaic]) # Binning *must* be consistent for all detectors if any(d.binning != detectors[0].binning for d in detectors[1:]): msgs.error('Binning is somehow inconsistent between detectors in the mosaic!') # Collect the offsets and rotations for *all unbinned* detectors in the # full instrument, ordered by the number of the detector. Detector # numbers must be sequential and 1-indexed. # See the mosaic documentattion. msc_geometry = HIRESMosaicLookUp.geometry expected_shape = msc_geometry[detid]['default_shape'] shift = np.array([(msc_geometry[detid]['blue_det']['shift'][0], msc_geometry[detid]['blue_det']['shift'][1]), (msc_geometry[detid]['green_det']['shift'][0], msc_geometry[detid]['green_det']['shift'][1]), (msc_geometry[detid]['red_det']['shift'][0], msc_geometry[detid]['red_det']['shift'][1])]) rotation = np.array([msc_geometry[detid]['blue_det']['rotation'], msc_geometry[detid]['green_det']['rotation'], msc_geometry[detid]['red_det']['rotation']]) # The binning and process image shape must be the same for all images in # the mosaic binning = tuple(int(b) for b in detectors[0].binning.split(',')) shape = tuple(n // b for n, b in zip(expected_shape, binning)) msc_sft = [None]*nimg msc_rot = [None]*nimg msc_tfm = [None]*nimg for i in range(nimg): msc_sft[i] = shift[i] msc_rot[i] = rotation[i] # binning is here in the PypeIt convention of (binspec, binspat), but the mosaic tranformations # occur in the raw data frame, which flips spectral and spatial msc_tfm[i] = build_image_mosaic_transform(shape, msc_sft[i], msc_rot[i], tuple(reversed(binning))) return Mosaic(mosaic_id, detectors, shape, np.array(msc_sft), np.array(msc_rot), np.array(msc_tfm), msc_order)
@property def allowed_mosaics(self): """ Return the list of allowed detector mosaics. Keck/HIRES only allows for mosaicing all three detectors. Returns: :obj:`list`: List of tuples, where each tuple provides the 1-indexed detector numbers that can be combined into a mosaic and processed by PypeIt. """ return [(1,2,3)] @property def default_mosaic(self): return self.allowed_mosaics[0]
[docs] def get_detector_par(self, det, hdu=None): """ Return metadata for the selected detector. Args: det (:obj:`int`): 1-indexed detector number. hdu (`astropy.io.fits.HDUList`_, optional): The open fits file with the raw image of interest. If not provided, frame-dependent parameters are set to a default. Returns: :class:`~pypeit.images.detector_container.DetectorContainer`: Object with the detector metadata. """ # Binning binning = '1,1' if hdu is None else self.get_meta_value(self.get_headarr(hdu), 'binning') # Detector 1 detector_dict1 = dict( binning = binning, det = 1, dataext = 1, specaxis = 0, specflip = False, spatflip = False, platescale = 0.135, darkcurr = 0.0, # e-/pixel/hour saturation = 65535., nonlinear = 0.7, # Website says 0.6, but we'll push it a bit mincounts = -1e10, numamplifiers = 1, ronoise = np.atleast_1d([2.8]), ) # Detector 2. detector_dict2 = detector_dict1.copy() detector_dict2.update(dict( det=2, dataext=2, ronoise=np.atleast_1d([3.1]) )) # Detector 3,. detector_dict3 = detector_dict1.copy() detector_dict3.update(dict( det=3, dataext=3, ronoise=np.atleast_1d([3.1]) )) # Set gain # https://www2.keck.hawaii.edu/inst/hires/instrument_specifications.html if hdu is None or hdu[0].header['CCDGAIN'].strip() == 'low': detector_dict1['gain'] = np.atleast_1d([1.9]) detector_dict2['gain'] = np.atleast_1d([2.1]) detector_dict3['gain'] = np.atleast_1d([2.1]) elif hdu[0].header['CCDGAIN'].strip() == 'high': detector_dict1['gain'] = np.atleast_1d([0.78]) detector_dict2['gain'] = np.atleast_1d([0.86]) detector_dict3['gain'] = np.atleast_1d([0.84]) else: msgs.error("Bad CCDGAIN mode for HIRES") # Instantiate detector_dicts = [detector_dict1, detector_dict2, detector_dict3] return detector_container.DetectorContainer( **detector_dicts[det-1])
[docs] def get_echelle_angle_files(self): """ Pass back the files required to run the echelle method of wavecalib Returns: list: List of files """ angle_fits_file = 'keck_hires_angle_fits.fits' composite_arc_file = 'keck_hires_composite_arc.fits' return [angle_fits_file, composite_arc_file]
[docs] def order_platescale(self, order_vec, binning=None): """ Return the platescale for each echelle order. This routine is only defined for echelle spectrographs, and it is undefined in the base class. Args: order_vec (`numpy.ndarray`_): The vector providing the order numbers. binning (:obj:`str`, optional): The string defining the spectral and spatial binning. Returns: `numpy.ndarray`_: An array with the platescale for each order provided by ``order``. """ det = self.get_detector_par(1) binspectral, binspatial = parse.parse_binning(binning) # Assume no significant variation (which is likely true) return np.ones_like(order_vec)*det.platescale*binspatial
[docs]def indexing(itt, postpix, det=None,xbin=1,ybin=1): """ Some annoying book-keeping for instrument placement. Parameters ---------- itt : int postpix : int det : int, optional Returns ------- """ # Deal with single chip if det is not None: tt = 0 else: tt = itt ii = int(np.round(2048/xbin)) jj = int(np.round(4096/ybin)) # y indices y1, y2 = 0, jj o_y1, o_y2 = y1, y2 # x x1, x2 = (tt%4)*ii, (tt%4 + 1)*ii if det is None: o_x1 = 4*ii + (tt%4)*postpix else: o_x1 = ii + (tt%4)*postpix o_x2 = o_x1 + postpix # Return return x1, x2, y1, y2, o_x1, o_x2, o_y1, o_y2
[docs]def hires_read_1chip(hdu,chipno): """ Read one of the HIRES detectors Parameters ---------- hdu : HDUList chipno : int Returns ------- data : ndarray oscan : ndarray """ # Extract datasec from header datsec = hdu[chipno].header['DATASEC'] detsec = hdu[chipno].header['DETSEC'] postpix = hdu[0].header['POSTPIX'] precol = hdu[0].header['PRECOL'] x1_dat, x2_dat, y1_dat, y2_dat = np.array(parse.load_sections(datsec)).flatten() x1_det, x2_det, y1_det, y2_det = np.array(parse.load_sections(detsec)).flatten() # This rotates the image to be increasing wavelength to the top #data = np.rot90((hdu[chipno].data).T, k=2) #nx=data.shape[0] #ny=data.shape[1] # Science data fullimage = hdu[chipno].data data = fullimage[x1_dat:x2_dat,y1_dat:y2_dat] # Overscan oscan = fullimage[:,y2_dat:] # Flip as needed if x1_det > x2_det: data = np.flipud(data) oscan = np.flipud(oscan) if y1_det > y2_det: data = np.fliplr(data) oscan = np.fliplr(oscan) # Return return data, oscan