pypeit.spectrographs.keck_esi module

Module for Keck/ESI specific methods.

class pypeit.spectrographs.keck_esi.KeckESISpectrograph[source]

Bases: Spectrograph

Child to handle Keck/ESI specific code

bpm(filename, det, shape=None, msbias=None)[source]

Generate a default bad-pixel mask.

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.

  • 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) – Master bias frame used to identify bad pixels


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:


camera = 'ESI'

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

check_frame_type(ftype, fitstbl, exprng=None)[source]

Check for frames of the provided type.


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

Return type:


compound_meta(headarr, meta_key)[source]

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


Metadata value read from the header(s).

Return type:



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.


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

Return type:


classmethod default_pypeit_par()[source]

Return the default parameters to use for this instrument.


Parameters required by all of PypeIt methods.

Return type:


ech_fixed_format = True

If an echelle spectrograph, this will be set to a boolean indicating whether it is a fixed format or tiltable echelle.

get_detector_par(det, hdu=None)[source]

Return metadata for the selected detector.

  • det (int) – 1-indexed detector number.

  • hdu (, optional) – The open fits file with the raw image of interest. If not provided, frame-dependent parameters are set to a default.


Object with the detector metadata.

Return type:


get_rawimage(raw_file, det, spectrim=None)[source]

Read the image

header_name = 'ESI'

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


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 = 'keck_esi'

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

ndet = 1

Number of detectors for this instrument.

property norders

Number of orders for this spectrograph. Should only defined for echelle spectrographs, and it is undefined for the base class.

order_platescale(order_vec, binning=None)[source]

Return the platescale for each echelle order.

This routine is only defined for echelle spectrographs, and it is undefined in the base class.

  • order_vec (numpy.ndarray) – The vector providing the order numbers.

  • binning (str, optional) – The string defining the spectral and spatial binning.


An array with the platescale for each order provided by order.

Return type:


property order_spat_pos

Return the expected spatial position of each echelle order.

property order_spat_width

Return the expected spatial width of each slit trace for each order, relative to the spatial size of the detector.

property orders

Return the order number for each echelle order.

pypeline = 'Echelle'

String used to select the general pipeline approach for this spectrograph.

scattered_light_archive(binning, dispname)[source]

Archival model parameters for the scattered light. These are based on best fits to currently available data.

  • binning (str, optional) – Comma-separated binning along the spectral and spatial directions; e.g., 2,1

  • dispname (str, optional) – Name of the disperser


  • x0 (numpy.ndarray) – A 1D array containing the best-fitting model parameters

  • bounds (tuple) – A tuple of two elements, containing two numpy.ndarray of the same length as x0. These two arrays contain the lower (first element of the tuple) and upper (second element of the tuple) bounds to consider on the scattered light model parameters.

property spec_min_max

Return the minimum and maximum spectral pixel expected for the spectral range of each order.

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          KECK                 KECK     str         False    longitude     -155.47833333333335  None     int, float  False    latitude      19.828333333333333   None     int, float  False    elevation     4160.000000000756    None     int, float  False    fratio        15                   None     int, float  False    diameter      10                   None     int, float  False    eff_aperture  72.3674              None     int, float  False   

Instance of TelescopePar providing telescope-specific metadata.