scopesim.effects.metis_lms_trace_list module

SpectralTraceList and SpectralTrace for the METIS LM spectrograph.

class scopesim.effects.metis_lms_trace_list.MetisLMSEfficiency(**kwargs)

Bases: TERCurve

Computes the grating efficiency (blaze function) for the METIS LMS.

The procedure is described in E-REP-ATC-MET-1016_1.0. For a given order (determined by the central wavelength) the grating efficiency is modelled as a squared sinc function of wavelength via the grating angle.

make_ter_curve(wcal, wavelen=None)

Compute the blaze function for the selected order.

class scopesim.effects.metis_lms_trace_list.MetisLMSImageSlicer(filename, ext_id='Aperture List', **kwargs)

Bases: ApertureMask

Treats the METIS LMS image slicer as an aperture mask effect.

This helps in building a FieldOfView object that combines the spatial field of the slicer with the spectral range covered by the LMS setting.

The effect differs from its parent class ApertureMask in the initialisation from the Aperture List extension of the trace file !OBS.trace_file.

class scopesim.effects.metis_lms_trace_list.MetisLMSSpectralTrace(hdulist, spslice, params, **kwargs)

Bases: SpectralTrace

SpectralTrace for the METIS LM spectrograph.

compute_interpolation_functions()

Define the transforms between (xi, lam) and (x, y).

The LMS transforms actually operate on phase rather than wavelength, hence the necessity of defining pre- and posttransforms on the lam variable.

fov_grid()

Provide information on the source space volume required by the effect.

Returns:

A dictionary with entries wave_min and wave_max, x_min, y_min,

x_max, y_max. Spatial limits refer to the sky and are given in

arcsec.

fp2sky(fp_x)

Convert position in FP2 to position on sky.

get_matrices()

Extract matrix from lms_dist_poly.txt.

Evaluate polynomial to obtain matrices A, B, AI and BI at grism angle given echelle order and slice number

Parameters:

orderint

Echelle order

spsliceint

Slice number

anglefloat

Grism angle in degrees

Returns:

dict of four np.arrays of shape (4, 4) each

get_waverange(det_mm_lims)

Determine wavelength range covered by spec. trace on image plane.

lam2phase(lam)

Convert wavelength to phase.

Phase is lam * order / (2 * grat_spacing).

Parameters:

lamndarray (float)

wavelength (um)

Returns:

Phasendarray

phase2lam(phase)

Convert phase to wavelength.

Wavelength is phase * 2 * grat_spacing / order

Parameters:

phasendarray (float)

phase (dimensionless)

Returns:

wavelengthndarray (um)

sky2fp(xi)

Convert position in arcsec to position in FP2.

class scopesim.effects.metis_lms_trace_list.MetisLMSSpectralTraceList(**kwargs)

Bases: SpectralTraceList

SpectralTraceList for the METIS LM spectrograph.

apply_to(obj, **kwargs)

See parent docstring.

make_spectral_traces()

Compute the transformations by interpolation.

rectify_cube(hdulist, xi_min=None, xi_max=None, interps=None, **kwargs)

Rectify an IFU observation into a data cube

The HDU list (or fits file) must have been created with the present OpticalTrain (or an identically configured one).

Parameters:

hduliststr or fits.HDUList

an ifu observation created with the present OpticalTrain

xi_min, xi_maxfloat [arcsec]

Spatial limits of the image slicer on the sky. For METIS LMS, these values need not be provided by the user.

interpslist of interpolation functions

If provided, there must be one for each image extension in hdulist. The functions go from pixels to the images and can be created with, e.g., RectBivariateSpline.

scopesim.effects.metis_lms_trace_list.echelle_setting(wavelength, grat_spacing, wcal_def)

Determine optimal echelle rotation angle for wavelength.

Parameters:

lambdafloat

central wavelength in microns

grat_spacingfloat

grating rule spacing in microns

wcal_def: fits.TableHDU, fits.BinTableHDU, Table, str

definition of the wavelength calibration parameters If str, interpreted as name of a fits file, with a table extension ‘WCAL’.

Returns:

a dict with entries

• Ord: echelle order

• Angle: grism angle

• Phase: phase