en:praktikum:sternspektren_baches

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en:praktikum:sternspektren_baches [2025/01/07 13:14] – [Reduce the data] rhainichen:praktikum:sternspektren_baches [2026/03/16 08:31] (current) – [Barycentric correction] rhainich
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    Star_1/    Star_1/
-      Darks/ +      darks/ 
-      Flatdarks/ +      flat_darks/ 
-      Flats/+      ThAr_darks/ 
 +      flats/
       ThAr/       ThAr/
       Star_1/       Star_1/
    Star_2/    Star_2/
-      Darks/ +      darks/ 
-      Flatdarks/+      flat_darks/
       ...       ...
  
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 </code> </code>
  
-In ''path_darks'', ''path_flat_darks'', ''path_flats'', ''path_wavelength_darks'', ''path_wavelength'', and ''path_spectra'' the corresponding subfolders are to be entered, which were created in section //Preparations//. ''out_path'' is the directory where the script places intermediate results. The reduced files (**master_dark.fit**, **master_flat.fit**, **master_wave.fit**, **master_spectrum.fit**) are stored in the local directory so that they are more easily available for the following analysis steps. +In ''path_darks'', ''path_flat_darks'', ''path_flats'', ''path_wavelength_darks'', ''path_wavelength'', and ''path_spectra'' the corresponding subfolders are to be entered, which were created in section //Preparations//. The variable ''path_wavelength_darks'' can be set to **'?'** if no darks were taken for the ThAr exposures. ''out_path'' is the directory where the script places intermediate results. The reduced files (**master_dark.fit**, **master_flat.fit**, **master_wave.fit**, **master_spectrum.fit**) are stored in the local directory so that they are more easily available for the following analysis steps. 
  
 If you want to mirror the recordings you have to set ''flip_images'' to ''True''. If the images should also be binned, set ''bin_images'' to ''True''. The binning factor can be determined via the variable ''binning_value''. If you want to mirror the recordings you have to set ''flip_images'' to ''True''. If the images should also be binned, set ''bin_images'' to ''True''. The binning factor can be determined via the variable ''binning_value''.
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 The identification of the individual orders, the identification of the emission lines in the ThAr spectrum, and the correlation between the pixel and the wavelength scale is performed by the //MIDAS// script ''calibrate/baches''. The call could look like: The identification of the individual orders, the identification of the emission lines in the ThAr spectrum, and the correlation between the pixel and the wavelength scale is performed by the //MIDAS// script ''calibrate/baches''. The call could look like:
  
-   calibrate/baches master_flat.fit master_thar.fit 26 26 24+   calibrate/baches master_flat.fit master_wave.fit 26 26 24
  
 The five parameters have the following meaning: The five parameters have the following meaning:
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    ===============================    ===============================
    Flat field  = master_flat.fit    Flat field  = master_flat.fit
-   Calibration lamp = master_thar.fit+   Calibration lamp = master_wave.fit
    Calibration table = thar.fit    Calibration table = thar.fit
    Num. of orders  = 0026    Num. of orders  = 0026
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 In this case, the script should be stopped by entering a ''2''. Afterwards the script can be restarted with a reduced number of orders, e.g.: In this case, the script should be stopped by entering a ''2''. Afterwards the script can be restarted with a reduced number of orders, e.g.:
  
-   calibrate/baches master_flat.fit master_thar.fit 23 20 20+   calibrate/baches master_flat.fit master_wave.fit 23 20 20
  
 A solid method is to gradually reduce the number of orders until the script executed successfully. Afterwards, the flatfield with the identified orders will be displayed in an external window (see below). It should be checked whether the marks of the orders are horizontal and whether they coincide with the actual orders that are visible on the flatfield. The left figure shows a successful test run, whereas the middle figure depicts a failure. The right figure shows a flatfield image taken with the QHY268M, where it can happen that //MIDAS// does not finish drawing all identified orders. From the order numbers, however, it can be assessed if all orders were successfully identified or not. The numbers also depend on whether the images are binned. As we usually use 2x2 binning, the above values should suffice. In case we have used 1x1 binning for the spectra however, you might have to double the second and third value. A solid method is to gradually reduce the number of orders until the script executed successfully. Afterwards, the flatfield with the identified orders will be displayed in an external window (see below). It should be checked whether the marks of the orders are horizontal and whether they coincide with the actual orders that are visible on the flatfield. The left figure shows a successful test run, whereas the middle figure depicts a failure. The right figure shows a flatfield image taken with the QHY268M, where it can happen that //MIDAS// does not finish drawing all identified orders. From the order numbers, however, it can be assessed if all orders were successfully identified or not. The numbers also depend on whether the images are binned. As we usually use 2x2 binning, the above values should suffice. In case we have used 1x1 binning for the spectra however, you might have to double the second and third value.
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 Depending on the number of identified orders, the plot range (second row) needs to be adjusted. You also can use this option to zoom in the spectrum. The parameters are Depending on the number of identified orders, the plot range (second row) needs to be adjusted. You also can use this option to zoom in the spectrum. The parameters are
  
-   plot/axes xmin, xmax, ymin, ymax, x axis label, y axis label+   plot/axes xmin,xmax, ymin,ymax, window_number x_axis_label y_axis_label
  
  4000 - 8000 Angstrom is the usual wavelength range covered by the spectrograph.   4000 - 8000 Angstrom is the usual wavelength range covered by the spectrograph. 
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 The radial velocity is usually given with respect to the barycenter, the center of mass of the solar system, to correct out the effect of the Earth's proper motion. The necessary correction can be calculated with the help of the script ''2_barycentric_velocity_correction.py''. The coordinates of the object, the observation time, the time zone, and the coordinates of the observatory must be specified: The radial velocity is usually given with respect to the barycenter, the center of mass of the solar system, to correct out the effect of the Earth's proper motion. The necessary correction can be calculated with the help of the script ''2_barycentric_velocity_correction.py''. The coordinates of the object, the observation time, the time zone, and the coordinates of the observatory must be specified:
  
-   ################################################################################## +<code Python> 
-   ############################ Script Parameters ################################### +################################################################################## 
-   ##################################################################################+############################ Script Parameters ################################### 
 +################################################################################## 
 + 
 +################   REPLACE EVERY "?" WITH ITS RESPECTIVE VALUE    ################
        
-   ################   REPLACE EVERY "?" WITH ITS RESPECTIVE VALUE    ################+##### Target coordinates ##### 
 +# enter the object's ICRS coordinates 
 +right_ascension                     = '?h ?m ?s'            # as hour angle: hour | minute | second 
 +declination                         = '+?deg ?m ?s'         # in deg | arcmin |arcsec
        
-   ##### Target coordinates ##### +##### Observation time ##### 
-   # enter the object's ICRS coordinates +observation_date                    = '????-??-?? ??:??:??' # enter the observation date formatted as 'YYYY-MM-DD HH:MM:SS'.  
-   right_ascension                     = '?h ?m ?s'            # as hour angle: hour | minute | second +                                                              Be careful, to enter the correct day if observations were made  
-   declination                         = '+?deg ?m ?s'         # in deg | arcmin |arcsec+                                                              past midnight! 
 +time_zone                           = '?'                     # type +1 for the central european time zone or +2 when time was  
 +                                                              switched to daylight saving
        
-   ##### Observation time ##### +##### Observatory ##### 
-   observation_date                    = '????-??-?? ??:??:??' # enter the observation date formatted as 'YYYY-MM-DD HH:MM:SS'.  +observatory_latitude                = '?'                     # values in degrees, north is positive 
-                                                                 Be careful, to enter the correct day if observations were made  +observatory_longitude               = '?'                     # values in degrees, east is positive 
-                                                                 past midnight! +observatory_height_above_MSL        = '?'                     # enter in meter 
-   time_zone                           = '?'                     # type +1 for the central european time zone or +2 when time was  +</code>
-                                                                 switched to daylight saving +
-    +
-   ##### Observatory ##### +
-   observatory_latitude                = '?'                     # values in degrees, north is positive +
-   observatory_longitude               = '?'                     # values in degrees, east is positive +
-   observatory_height_above_MSL        = '?'                     # enter in meter+
  
 Execute the script with: Execute the script with:
  • en/praktikum/sternspektren_baches.1736255645.txt.gz
  • Last modified: 2025/01/07 13:14
  • by rhainich