Interpolation of stellar spectra and templates¶

Within ASTRA, the individual Frame's and the Stellar templates have a common parent class:

from ASTRA.Components.Modelling import Spectral_Modelling

Due to the nature of ASTRA internals, the configurations from this parent class are not see through the config_help function when called on either of those two objects.

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from ASTRA.Components.Modelling import Spectral_Modelling

Spectral_Modelling.config_help()
from ASTRA.Components.Modelling import Spectral_Modelling

Spectral_Modelling.config_help()

Configurations:

Name:: SAVE_DISK_SPACE
	Description:: Save disk space in the outputs if different than None
	Mandatory:: False
	Default value:: DISK_SAVE_MODE.DISABLED
	Constraints:: Value from list <<enum 'DISK_SAVE_MODE'>>
 
Name:: WORKING_MODE
	Description:: How to store the output files. If one-shot, overwrites all files, otherwise updates products
	Mandatory:: False
	Default value:: WORKING_MODE.ONE_SHOT
	Constraints:: Value from list <<enum 'WORKING_MODE'>>
 
Name:: INTERPOL_MODE
	Description:: None
	Mandatory:: False
	Default value:: SPECTRA_INTERPOL_MODE.SPLINES
	Constraints:: Value from list <<enum 'SPECTRA_INTERPOL_MODE'>>
 
Name:: SPLINE_TYPE
	Description:: None
	Mandatory:: False
	Default value:: SPLINE_INTERPOL_MODE.CUBIC_SPLINE
	Constraints:: Value from list <<enum 'SPLINE_INTERPOL_MODE'>>
 
Name:: INTERPOLATION_ERR_PROP
	Description:: None
	Mandatory:: False
	Default value:: INTERPOLATION_ERR_PROP.interpolation
	Constraints:: Value from list <<enum 'INTERPOLATION_ERR_PROP'>>
 
Name:: NUMBER_WORKERS
	Description:: None
	Mandatory:: False
	Default value:: 1
	Constraints:: Value inside interval <(0, inf)>; Edges: True
 
Name:: FLUX_SMOOTH_CONFIGS
	Description:: Configure a possible flux smoothing before template construction
	Mandatory:: False
	Default value:: FLUX_SMOOTH_CONFIGS.NONE
	Constraints:: Value from list <<enum 'FLUX_SMOOTH_CONFIGS'>>
 
Name:: FLUX_SMOOTH_WINDOW_SIZE
	Description:: Number of points that will be used for the filter to smooth the spectra
	Mandatory:: False
	Default value:: 15
	Constraints:: Value inside interval <(0, inf)>; Edges: True
 
Name:: FLUX_SMOOTH_DEG
	Description:: Degree of the polynomial that will be used for the filter to smooth the spectra
	Mandatory:: False
	Default value:: 2
	Constraints:: Value inside interval <(0, inf)>; Edges: True
 
Name:: FLUX_SMOOTH_ORDER
	Description:: Order in which we smooth the flux (before, after or both)
	Mandatory:: False
	Default value:: FLUX_SMOOTH_ORDER.AFTER
	Constraints:: Value from list <<enum 'FLUX_SMOOTH_ORDER'>>

This parent class unlocks a common API for the interpolation of spectra (either in the form of a single observation or in the form of a stellar template).

This interface will run a serial set of operations:

If configured to do so, smooth the stellar spectra before the interpolation
Apply/remove a given RV shift to the wavelengths
Interpolate the spectra and compute new flux uncertainties (based on configuration)
If configured to do so, smooth the stellar spectra after the interpolation

This function does not compute the limits of interpolation (i.e., it will extrapolate if the new_wavelengths are outside the valid ranges of the underlying data)

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import matplotlib.pyplot as plt

from ASTRA.Instruments import ESPRESSO
from ASTRA.utils import choices

frame = ESPRESSO(file_path="/home/amiguel/spectra_collection/ESPRESSO/proxima/r.ESPRE.2019-07-03T01:43:39.634_S2D_A.fits",
                 user_configs={"INTERPOL_MODE": choices.SPECTRA_INTERPOL_MODE.SPLINES,
                               "SPLINE_INTERPOL_MODE": choices.SPLINE_INTERPOL_MODE.CUBIC_SPLINE
                               }
                 )
frame.generate_root_path("tmp")

spectral_order = 50 
wave, flux, err, mask = frame.get_data_from_spectral_order(order=spectral_order)

fig, axis = plt.subplots()
axis.scatter(wave[~mask], flux[~mask], color="black")

waves_to_interpol = wave[~mask][1000:1500]
for spline_mode in [choices.SPLINE_INTERPOL_MODE.CUBIC_SPLINE, choices.SPLINE_INTERPOL_MODE.QUADRATIC_SPLINE]:
    new_flux, new_err = frame.interpolate_spectrum_to_wavelength(order = 50,
                                            new_wavelengths=waves_to_interpol,
                                            shift_RV_by=10,
                                            RV_shift_mode="apply",)
    
    axis.scatter(waves_to_interpol, new_flux, label=spline_mode.name, s=6)
axis.legend(ncol=3, loc=4, bbox_to_anchor=(1,1))
axis.set_xlim([waves_to_interpol[0], waves_to_interpol[-1]])
import matplotlib.pyplot as plt

from ASTRA.Instruments import ESPRESSO
from ASTRA.utils import choices

frame = ESPRESSO(file_path="/home/amiguel/spectra_collection/ESPRESSO/proxima/r.ESPRE.2019-07-03T01:43:39.634_S2D_A.fits",
                 user_configs={"INTERPOL_MODE": choices.SPECTRA_INTERPOL_MODE.SPLINES,
                               "SPLINE_INTERPOL_MODE": choices.SPLINE_INTERPOL_MODE.CUBIC_SPLINE
                               }
                 )
frame.generate_root_path("tmp")

spectral_order = 50 
wave, flux, err, mask = frame.get_data_from_spectral_order(order=spectral_order)

fig, axis = plt.subplots()
axis.scatter(wave[~mask], flux[~mask], color="black")

waves_to_interpol = wave[~mask][1000:1500]
for spline_mode in [choices.SPLINE_INTERPOL_MODE.CUBIC_SPLINE, choices.SPLINE_INTERPOL_MODE.QUADRATIC_SPLINE]:
    new_flux, new_err = frame.interpolate_spectrum_to_wavelength(order = 50,
                                            new_wavelengths=waves_to_interpol,
                                            shift_RV_by=10,
                                            RV_shift_mode="apply",)
    
    axis.scatter(waves_to_interpol, new_flux, label=spline_mode.name, s=6)
axis.legend(ncol=3, loc=4, bbox_to_anchor=(1,1))
axis.set_xlim([waves_to_interpol[0], waves_to_interpol[-1]])

2025-04-14 22:44:47.206 | INFO     | ASTRA.base_models.Frame:__init__:252 - Creating frame from: /home/amiguel/spectra_collection/ESPRESSO/proxima/r.ESPRE.2019-07-03T01:43:39.634_S2D_A.fits
2025-04-14 22:44:47.208 | WARNING  | ASTRA.Components.SpectrumComponent:regenerate_order_status:96 - Resetting order status of Frame - ESPRESSO
2025-04-14 22:44:47.224 | DEBUG    | ASTRA.base_models.Frame:assess_bad_orders:710 - Rejecting spectral orders
2025-04-14 22:44:47.227 | INFO     | ASTRA.base_models.Frame:assess_bad_orders:740 - Frame None rejected 37 orders for having SNR smaller than 5: 0-36
2025-04-14 22:44:47.229 | DEBUG    | ASTRA.base_models.Frame:load_S2D_data:861 - Opening the S2D arrays from r.ESPRE.2019-07-03T01:43:39.634_S2D_A.fits
2025-04-14 22:44:47.248 | WARNING  | ASTRA.Instruments.ESO_PIPELINE:load_ESO_DRS_S2D_data:327 - Not applying correction to blue-red flux balance!
2025-04-14 22:44:47.319 | DEBUG    | ASTRA.base_models.Frame:build_mask:627 - Cleaning wavelength regions from []
2025-04-14 22:44:47.320 | DEBUG    | ASTRA.base_models.Frame:build_mask:645 - Removed 0 regions ()
2025-04-14 22:44:47.321 | DEBUG    | ASTRA.base_models.Frame:build_mask:671 - Ensuring that we have increasing wavelengths
2025-04-14 22:44:47.333 | DEBUG    | ASTRA.base_models.Frame:build_mask:677 - Took 0 seconds ()
2025-04-14 22:44:47.335 | DEBUG    | ASTRA.base_models.Frame:assess_bad_orders:710 - Rejecting spectral orders
2025-04-14 22:44:47.359 | DEBUG    | ASTRA.base_models.Frame:assess_bad_orders:723 - Frame None rejected 37 orders due for having less than 0.25 valid pixels: 0-36
2025-04-14 22:44:47.361 | INFO     | ASTRA.base_models.Frame:assess_bad_orders:740 - Frame None rejected 37 orders for having SNR smaller than 5: 0-36

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(4486.688103074458, 4490.840682985041)

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