Data products¶

These data products are saved to disk as FITS files. MEGARA DRP makes use of the FITS headers to record information about the data processing. This information may be recorded using other methods as well, such as the GTC Database.

The following headers are included in all image data products and record information about the version of Numina and the name and version of the recipe used.

NUMXVER = '0.13.0   '           / Numina package version
NUMRNAM = 'BiasRecipe'          / Numina recipe name
NUMRVER = '0.1.0   '            / Numina recipe version
NUMTYP  = 'TARGET  '            / Data product type

HISTORY keywords may be used also, but the information in these keyword may not be easily indexed.

Master Bias frames¶

Bias frames are produced by the recipe BiasRecipe. Each bias frame is a multiextension FITS file with the following extensions.

Extension name Type Version Contents

PRIMARY Primary The bias level

VARIANCE Image Variance of the bias level

MAP Image Number of pixels used to compute the bias level

Master bias frames are represented by MasterBias.

Master Dark frames¶

Master dark frames are produced by the recipe DarkRecipe. Each dark frame is a multiextension FITS file with the following extensions.

Extension name Type Version Contents

PRIMARY Primary The dark level

VARIANCE Image Variance of the dark level

MAP Image Number of pixels used to compute the dark level

Master dark frames are represented by MasterDark.

Master Bad Pixel Mask¶

Master Bad Pixel Mask is produced by the recipe BadPixelsMaskRecipe. Each bad pixel mask frame is a multiextension FITS file with the following extensions.

Extension name Type Version Contents

PRIMARY Primary The Bad Pixel Mask level

Master bad pixel mask frames are represented by MasterBPM.

Master Traces¶

Master Fiber Flat is produced by the recipe TraceMapRecipe. The result is a YAML file where each one of the records belongs to a given fiber in the RSS file. Moreover, each one of the records has the next information:

Field Type Contents

boxid Integer Number of the box

fibid Integer Number of the fiber

fitparms Primary Polyfit algorithm result

start Integer X-Coordenate in the Flat image

stop Integer X-Coordenate in the Flat image

In the following, a real example of the fourth fiber which is in the first box can be seen in the yaml format:

- boxid: 1
  fibid: 4
  fitparms: [2.6909627476636523e-18, -3.0949058966515047e-14, 1.872326137294402e-10,1.1602592442769502e-06, -0.0009443161994027746, 262.01840282676613]
  start: 4
  stop: 3594

Master Tracemap files are represented by TraceMap.

Master Weights¶

Master weights file is produced by the recipe WeightsRecipe. This is a .tar file which is made up of 4096 .npz files (one per fiber). These are numpy files where the ndarray are stored.

This file is compulsary to generate the master fiber flat.

Master weights files are represented by MasterWeights.

Master Wavelength Calibration¶

Master wavelength calibration is produced by the recipe ArcRecipe. The result is a JSON file where each one of the records belongs to a given fiber in the RSS file. Moreover, each one of the records or apertures has the next fields:

Field Type Contents

features List List with the arc’s information

function Dictionary Number of pixels used to compute the dark level

id Integer Number the corresponding fiber

Additionally, each one of the elements that belongs to the features corresponds to each one of the arc lines that has been found in the RSS image. The dictionary that each element has, contains the next information:

Field Type Contents

category String Type of the arc

flux Float Flux of the arc

fwhm Float Full Width at Half Maximum of the arc

reference Float Line in the Catalog lines

wavelength Float Predicted line

xpos Float X-coordenate of the arc in the RSS image

ypos Float Y-coordenate of the arc in the RSS image

Finally, the function dictionary has three elements: coefficients, method and order fields. Coefficients has the result of executing the polynomial.polyfit numpy method. Method field has the name of the algorithm used. Order field has the polynomial degree.

In the following, an example of the first fiber of a real JSON file with only two arc lines can be seen:

{
  "aperture": {
    "features": [
      {
        "category": "E",
        "flux": 50212.563405324945,
        "fwhm": 3.438967092459162,
        "reference": 6013.2816999999995,
        "wavelength": 6013.2847301957181,
        "xpos": 33.267395825699928,
        "ypos": 251.10097403866305
      },
    ],
    "function": {
      "coefficients": [6001.573165443434,0.35298729563735487,-2.898410563853586e-05,1.858317850662985e-08,-8.411429549924489e-12,1.4341696725726076e-15],
      "method": "least squares",
      "order": 5
    },
    "id": 2
  }

Master Wavelength calibration file is represented by WavelengthCalibration.

Master Fiber Flat¶

Master Fiber Flat is produced by the recipe FiberFlatRecipe. Each master fiber flat frame is a multiextension FITS file with the following extensions.

Extension name Type Version Contents

PRIMARY Primary The Fiber Flat level

Master fiber flats frames are represented by MasterFiberFlat.

Master Slit Flat¶

Master Slit Flat is produced by the recipe SlitFlatRecipe. Each slit flat frame is a multiextension FITS file with the following extensions.

Extension name Type Contents

PRIMARY Primary The Slit Flat level

Masterslit flat frames are represented by MasterSlitFlat.

Master Twilight Flat¶

Master Twilight Flat is produced by the recipe TwilightFiberFlatRecipe. Each twilight flat frame is a multiextension FITS file with the following extensions.

Extension name Type Version Contents

PRIMARY Primary The Twilight Flat level

Master twilight flat frames are represented by MasterTwilightFlat.

Master LCB¶

Master lcb image is produced by the recipe LCBImageRecipe.

Extension name Type Version Contents

PRIMARY Primary The LCB Image level

Master lcb image is represented by MasterFiberFlat.

Master MOS¶

Master mos image is produced by the recipe MOSImageRecipe.

Extension name Type Version Contents

PRIMARY Primary The MOS Image level

Master mos image is represented by MasterFiberFlat.

Master LCB Fast Mapping¶

Master lcb fast mapping image is produced by the recipe LCBFastMappingRecipe.

Extension name Type Version Contents

PRIMARY Primary The LCB Fast Mapping Image level

Master lcb fast mapping image is represented by MasterFiberFlat.

Master LCB std Star¶

Master lcb standard star image is produced by the recipe LCBStandardRecipe.

Extension name Type Version Contents

PRIMARY Primary The LCB std Star Image level

Master lcb standard star image is represented by MasterFiberFlat.

Master MOS std Star¶

Master mos standard star image is produced by the recipe MOSStandardRecipe.

Extension name Type Version Contents

PRIMARY Primary The MOS std Star Image level

Master mos standard star image is represented by MasterFiberFlat.

Master Sensitivity Star¶

Master sensitivity star image is produced by the recipe SensivityStarRecipe.

Extension name Type Version Contents

PRIMARY Primary The Sensitivity Star Image level

Master sensitivity star image is represented by MasterFiberFlat.

Master Extinction Star¶

Master extinction star image is produced by the recipe SensivityStarRecipe.

Extension name Type Version Contents

PRIMARY Primary The Extinction Star Image level

Master extinction star image is represented by MasterFiberFlat.