pypeit.spectrographs.mmt_binospec module

Module for MMT/BINOSPEC specific methods.

class pypeit.spectrographs.mmt_binospec.MMTBINOSPECSpectrograph

Bases: Spectrograph

Child to handle MMT/BINOSPEC specific code

static _parse_slitmask_data(filename, det)

bino_get_slit_region(filename, det=None, Nx=4096, Ny=4112, pady=0)

Compute the pixel-space rectangular regions for each slit in a Binospec mask.

This function reads the slitmask design from a FITS file (or an already-loaded SlitMask object), converts slit and object positions from mask coordinates to pixel coordinates, and determines the x/y pixel boundaries for each slit on the detector. It returns these boundaries along with the updated slitmask object.

Parameters:

• filename (str) – Path to the slitmask FITS file. Must be provided unless the slitmask is already loaded via self.get_slitmask.

• det (int, optional) – Detector number (1 or 2). Must be specified.

• Nx (int, optional) – Detector size in the x-direction (default: 4096 pixels).

• Ny (int, optional) – Detector size in the y-direction (default: 4112 pixels).

• pady (float, optional) – Additional padding (in pixels) applied to the slit boundaries (default: 0).

Returns:

• region (list) – A list containing: - slit_x_range : array of x-boundaries for each slit [Nslits, 2] - slit_y_range : array of y-boundaries for each slit [Nslits, 2] - x_slitobj_pix : array of x pixel positions for slit objects - y_slitobj_pix : array of y pixel positions for slit objects

• slitmask (SlitMask) – The updated SlitMask object containing slit geometry and metadata.

Notes

• Converts mask coordinates to pixel coordinates using the appropriate scale factor.

• Handles detector 2 by reversing slit order and applying a vertical flip.

• Slit boundaries are clipped to remain within detector dimensions.

bpm(filename, det, shape=None, msbias=None)

Generate a default bad-pixel mask.

Loads a pre-built static BPM from the IDL pipeline calibration data (badpix_binospec.fits + hard-coded bad columns and detector trap regions from bino_mosaic.pro).

Even though they are both optional, either the precise shape for the image (shape) or an example file that can be read to get the shape (filename using get_image_shape()) must be provided.

Parameters:

• filename (str or None) – An example file to use to get the image shape.

• det (int) – 1-indexed detector number to use when getting the image shape from the example file.

• shape (tuple, optional) – Processed image shape Required if filename is None Ignored if filename is not None

• msbias (numpy.ndarray, optional) – Processed bias frame used to identify bad pixels

Returns:

An integer array with a masked value set to 1 and an unmasked value set to 0. All values are set to 0.

Return type:

numpy.ndarray

camera = 'BINOSPEC'

Name of the spectrograph camera or arm. This is used by specdb, so use that naming convention

check_frame_type(ftype, fitstbl, exprng=None)

Check for frames of the provided type.

Parameters:

• ftype (str) – Type of frame to check. Must be a valid frame type; see frame-type Definitions.

• fitstbl (astropy.table.Table) – The table with the metadata for one or more frames to check.

• exprng (list, optional) – Range in the allowed exposure time for a frame of type ftype. See pypeit.core.framematch.check_frame_exptime().

Returns:

Boolean array with the flags selecting the exposures in fitstbl that are ftype type frames.

Return type:

numpy.ndarray

compound_meta(headarr, meta_key)

Methods to generate metadata requiring interpretation of the header data, instead of simply reading the value of a header card.

Parameters:

• headarr (list) – List of astropy.io.fits.Header objects.

• meta_key (str) – Metadata keyword to construct.

Returns:

Metadata value read from the header(s).

Return type:

object

config_specific_par(inp, inp_par=None)

Modify the PypeIt parameters to hard-wired values used for specific instrument configurations.

Parameters:

• inp (str, list, Path, astropy.io.fits.Header, astropy.table.Table) – Input filename, an astropy.io.fits.Header object, or a list of astropy.io.fits.Header objects. Or a row from the metadata table.

• inp_par (ParSet, optional) – Parameter set used for the full run of PypeIt. If None, use default_pypeit_par().

Returns:

The PypeIt parameter set adjusted for configuration specific parameter values.

Return type:

ParSet

configuration_keys()

Return the metadata keys that define a unique instrument configuration.

This list is used by PypeItMetaData to identify the unique configurations among the list of frames read for a given reduction.

Returns:

List of keywords of data pulled from file headers and used to constuct the PypeItMetaData object.

Return type:

list

classmethod default_pypeit_par()

Return the default parameters to use for this instrument.

Returns:

Parameters required by all of PypeIt methods.

Return type:

PypeItPar

get_detector_par(det, hdu=None)

Return metadata for the selected detector.

Parameters:

• det (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:

Object with the detector metadata.

Return type:

DetectorContainer

get_maskdef_slitedges(filename=None, det=1, debug=None, binning=None, trc_path=None)

Provides the slit edges positions predicted by the slitmask design.

This method is not defined for all spectrographs. This base-class method raises an exception. This may be because use_maskdesign has been set to True for a spectrograph that does not support it.

Parameters:

• filename (str, list, optional:) – Name of the file holding the mask design info or the maskfile and wcs_file in that order

• det (int, optional) – Detector number

• debug (bool, optional) – Flag to run in debugging mode

• trc_path (str, optional) – Path to the first trace file used to generate the trace flat

• binning (str, optional) – String with the comma-separated number of pixels binned in each dimension of the flat-field image. Order must be spectral then spatial.

Returns:

• top_edges (numpy.ndarray) – Predicted locations of the top edges of the slits in spatial pixel coordinates.

• bot_edges (numpy.ndarray) – Predicted locations of the bottom edges of the slits in spatial pixel coordinates.

• sortindx (numpy.ndarray) – Indices of the slits in the provided slitmask object that orders the slits from left to right, in the PypeIt orientation.

• slitmask (SlitMask) – Slit mask metadata read from the provided input file(s).

Notes

• Edges are sorted by bottom edge y-coordinate to order slits spatially.

get_rawimage(raw_file, det)

Read raw images and generate a few other bits and pieces that are key for image processing.

Parameters:

• raw_file (str) – File to read

• det (int) – 1-indexed detector to read

Returns:

• detector_par (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 (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.

get_slitmask(filename, det=1)

Parse the slitmask data from a raw file into slitmask, a SlitMask object.

Parameters:

• filename (str) – Name of the file to read.

• det (int, optional) – 1-indexed detector number to read the slitmask for. Must be either 1 or 2 for MMT/Binospec.

Returns:

The slitmask data read from the file. The returned object is the same as slitmask.

Return type:

SlitMask

Notes

• Target-slit alignment is characterized via distances from slit edges.

• Slit corners and on-sky positions are stored for each target.

header_name = 'Binospec'

Name of the spectrograph camera or arm from the Header. Usually the INSTRUME card.

init_meta()

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 meta.

name = 'mmt_binospec'

The name of the spectrograph. See Spectrographs for the currently supported spectrographs.

ndet = 2

Number of detectors for this instrument.

nonlinearity_coeffs = array([[ 0.00000000e+00,  1.00400089e+00, -1.39235362e-06,          8.31711824e-12, -1.20653479e-17],        [ 0.00000000e+00,  1.00361458e+00, -1.29223833e-06,          6.93723177e-12, -9.67406255e-18],        [ 0.00000000e+00,  1.00269542e+00, -9.29361806e-07,          5.97902827e-12, -2.30257302e-17],        [ 0.00000000e+00,  1.00339616e+00, -8.47134521e-07,          7.92441693e-12, -4.46542834e-17],        [ 0.00000000e+00,  1.00727205e+00, -1.69093388e-06,          2.07225055e-11, -1.62655178e-16],        [ 0.00000000e+00,  1.00858745e+00, -2.35668901e-06,          2.40641019e-11, -1.50286358e-16],        [ 0.00000000e+00,  1.00728526e+00, -1.80779473e-06,          1.73427719e-11, -1.01685780e-16],        [ 0.00000000e+00,  1.00845168e+00, -2.02050567e-06,          2.97587091e-11, -2.65508521e-16]])

plot_mask(filename, det=None, save_dir=None)

Plot the slit mask layout and target positions for one or both detectors.

This function retrieves slit region data for a given Binospec mask and plots the rectangular slit outlines and target positions for detector 1, detector 2, or both. It is useful for visually validating mask design and target alignment.

Parameters:

• filename (str) – Path to the mask design file (e.g., a JSON file containing slit definitions).

• det (int or str) – Specifies which detector(s) to plot. Accepts 1, 2, or ‘both’.

• save_dir (str, optional) – If provided, the plot will be saved as a PNG in the given directory.

Returns:

• region_1 (tuple, optional) – Slit region and target position data for detector 1, if requested.

• region_2 (tuple, optional) – Slit region and target position data for detector 2, if requested.

raw_header_cards()

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 configuration_keys() or are used in config_specific_par() for a particular spectrograph, if different from the name of the PypeIt metadata keyword.

This list is used by subheader_for_spec() to include additional FITS keywords in downstream output files.

Returns:

List of keywords from the raw data files that should be propagated in output files.

Return type:

list

supported = True

Flag that PypeIt code base has been sufficiently tested with data from this spectrograph that it is officially supported by the development team.

telescope = Parameter     Value                Default  Type        Callable ---------------------------------------------------------------- name          MMT                  KECK     str         False    longitude     -110.87750000000003  None     int, float  False    latitude      31.68094444444444    None     int, float  False    elevation     2319.9999999995903   None     int, float  False    fratio        None                 None     int, float  False    diameter      6.5                  None     int, float  False    eff_aperture  None                 None     int, float  False   

Instance of TelescopePar providing telescope-specific metadata.

update_edgetracepar(par)

This method is used in pypeit.edgetrace.EdgeTraceSet.maskdesign_matching() to update EdgeTraceSet parameters when the slitmask design matching is not feasible because too few slits are present in the detector.

Parameters:

par (pypeit.par.pypeitpar.EdgeTracePar) – The parameters used to guide slit tracing.

Returns:

pypeit.par.pypeitpar.EdgeTracePar The modified parameters used to guide slit tracing.

url = 'https://lweb.cfa.harvard.edu/mmti/binospec.html'

Reference url

pypeit.spectrographs.mmt_binospec._plot_region(ax, region, color, side_label)

pypeit.spectrographs.mmt_binospec.binospec_read_amp(inp, ext)

Read one amplifier of an MMT BINOSPEC multi-extension FITS image

Parameters:

• inp (str, astropy.io.fits.HDUList) – The input FITS file name or already opened HDU list.

• ext (int) – FITS extension to read

Returns:

• data (numpy.ndarray) – Array with data from the data section of the image.

• overscan (numpy.ndarray) – Array with the overscan section of the image.

• datasec (str) – String with the data section in IRAF format, e.g. ‘[x1:x2,y1:y2]’.

• biassec (str) – String with the bias section in IRAF format, e.g. ‘[x1:x2,y1:y2]’.