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.
Generic types¶
Processed Frame¶
Processed Frame is the type of any image produced by the pipeline that represents a view of the detector. Its size may be 4096x4112 for trimmed images or 4196x4212 for unprocessed, raw images.
Processed Frame is represented by ProcessedFrame
.
Processed RSS¶
Processed Row Stacked Spectra is the type of any image produced by the pipeline that represents a view of the focal plane, using extracted fibers. It will have 623 rows in LCB mode and 644 rows in MOS mode, each row representing the extracted spectrum of one fiber. The number of columns will be 4112 or larger, depending on the stage of the reduction.
Procesed RSS images will tipically have a FIBERS extension.
Processed RSS is represented by ProcessedRSS
.
Processed Spectrum¶
Processed spectrum is the type of any image produced by the pipeline that represents the spectrum of one object. Its data content will be a 1D array.
Processed Spectrum is represented by ProcessedSpectrum
.
Calibrations¶
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 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 Traces¶
Master Fiber Flat is produced by the recipe TraceMapRecipe
.
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 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 Wavelength Calibration¶
Master wavelength calibration is produced by the recipe ArcCalibrationRecipe
.
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
FIBERS
Image
Description of the focal plane
Master fiber flats frames are represented by MasterFiberFlat
.
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
FIBERS
Image
Description of the focal plane
Master twilight flat frames are represented by MasterTwilightFlat
.
Master Sensitivity¶
Master sensitivity star image is produced by the recipe Recipe
.
Extension name
Type
Version
Contents
PRIMARY
Primary
The Sensitivity Star Image level
Master sensitivity star image is represented by MasterSensitivity
.
Master Extinction¶
Master extinction star image is produced by the recipe Recipe
.
Extension name
Type
Version
Contents
PRIMARY
Primary
The Extinction Star Image level
Master extinction star image is represented by Extinction
.
Reference calibrations¶
The following types represent types used for calibration, but that are not the result of any recipe. Examples of this type are the spectra of flux standars or the tables of spectral lines of calibration lamps.
Reference Spectrum¶
A tabular representation of the spectral energy distribution of a standard star. The first column contains wavelength (in Angstroms) and the second column the flux in erg/s/cm^2/Angstrom
Reference spectrum is represented by ReferenceSpectrum
.