Starlink Project
Starlink User Note 86.21

Keith Shortridge, Horst Meyerdierks, Malcolm Currie,
Martin Clayton, Jon Lockley, Anne Charles, Clive Davenhall,
Mark Taylor, Tim Ash, Tim Wilkins, Dave Axon,
John Palmer, Anthony Holloway and Vito Graffagnino

2004 February 17

A general data reduction system

Version 5.6-3 

User’s Guide


Figaro is a general-purpose data reduction package. The programs it contains can be used to process a wide range of images and spectra.

Figaro can be run in a command-oriented way from the Unix shell or from within ICL. Figaro supports the Starlink NDF data format by default, plus all foreign formats for which conversion utilities exist. These additional formats include Figaro’s old DST format, FITS, and IRAF.

This document offers novice users an easy starting point to using Figaro, and more experienced users a cookbook of a range of problems which can be addressed using the package. It describes version 5.6-3 of Figaro.


1 Introduction
 1.1 What is Figaro?
 1.2 This document
 1.3 History
2 Beginners
 2.1 Unix setup
 2.2 Starting Figaro
  2.2.1 Starting Figaro from the Unix shell
  2.2.2 Starting Figaro from ICL
  2.2.3 Starting Figaro from IRAF
  2.2.4 Inter-operability between Figaro and other packages
 2.3 Getting help
  2.3.1 Help from within the Unix shell
  2.3.2 Help from within ICL
  2.3.3 Help via the WWW
  2.3.4 Asking for advice
 2.4 Looking at a spectrum
 2.5 Looking at an image
  2.5.1 The ‘image’ command
  2.5.2 Advanced use of ‘image’
  2.5.3 Adding colour
 2.6 Image display in monochrome
 2.7 Paper copies
  2.7.1 Paper copy by cheating
 2.8 Examining data
 2.9 Doing simple things
3 Advanced users
 3.1 Parameters: Controlling commands
  3.1.1 What is the parameter system?
  3.1.2 Parameters on the command line
  3.1.3 Prompted parameters
  3.1.4 Output parameters
  3.1.5 Syntax conflicts
 3.2 Data files: Internal details
  3.2.1 HDS files
  3.2.2 NDF format
  3.2.3 NDF sections
  3.2.4 Foreign formats
  3.2.5 DST format
  3.2.6 Figaro Extension to NDF and DST structures
  3.2.7 The Specdre Extension
  3.2.8 The Contents of the Twodspec Longslit Results Structure
 3.3 Error propagation
  3.3.1 How is the error information stored?
  3.3.2 Getting error information into a file
  3.3.3 How are the errors propagated?
  3.3.4 Reducing data with error propagation
  3.3.5 Flat fielding
  3.3.6 Sky subtraction
  3.3.7 Optimal extraction
  3.3.8 My data are full of cosmic rays—how do I get rid of them?
  3.3.9 Zero Variances
 3.4 Standard Figaro directories
4 Doing more complex things
 4.1 Flats
  4.1.1 Image data
  4.1.2 Spectral data
 4.2 B-Stars
 4.3 Filters
 4.4 Spiketra
 4.5 Flux calibration
  4.5.1 Units
  4.5.2 Standard files
  4.5.3 The final step
  4.5.4 Published standards
  4.5.5 First step—Turning the table into a spiketrum
  4.5.6 Second step—for Oke & Gunn data
  4.5.7 Second step—for Filippenko & Greenstein data
  4.5.8 An alternative second step—Filippenko & Greenstein data
  4.5.9 The final step revisited
  4.5.10 AB magnitudes, and a test
  4.5.11 Manually setting the exposure time
  4.5.12 Summary
 4.6 FFT
  4.6.1 Complex data structures
  4.6.2 Creating a complex data structure
  4.6.3 Going smoothly to zero at the ends
  4.6.4 Taking the Fourier transform
  4.6.5 Extracting the real and imaginary parts
  4.6.6 Operations on complex data
  4.6.7 Complex filters and data smoothing
  4.6.8 Cross correlation, and a sequence something like ‘scross’
  4.6.9 Summary of Figaro FFT routines
  4.6.10 References
 4.7 S-Distortion
  4.7.1 Usual sequence
  4.7.2 Self-correcting objects
  4.7.3 Use of ‘cdist’ parameter ‘rotate’
  4.7.4 Making do without an image display
 4.8 Wavelength calibration
  4.8.1 Discrete and continuous channel numbers
  4.8.2 Wavelength arrays
  4.8.3 The ‘arc’ command
  4.8.4 Applying an arc fit to other spectra
  4.8.5 Linear wavelength scales—scrunching
  4.8.6 Two-dimensional scrunching
  4.8.7 Sequence summary
 4.9 Extinction
  4.9.1 Reference
 4.10 Arc—A Figaro program for arc wavelength calibration
  4.10.1 Arc line lists
  4.10.2 Other initial prompts
  4.10.3 The line selection process
  4.10.4 Subtleties—this bit is worth reading!
  4.10.5 Moving about the spectrum and other commands
  4.10.6 Fitting and editing—the menu stage
  4.10.7 The automatic line-finding facility
  4.10.8 On the way out of ‘arc’
  4.10.9 Working with shifted spectra
 4.11 Abline—A Figaro program for absorption line analysis
  4.11.1 Introduction
  4.11.2 Running ‘abline’
  4.11.3 Line parameter estimation
  4.11.4 Conclusion
 4.12 Gauss—A Figaro program for interactive Gaussian fitting
  4.12.1 Introduction
  4.12.2 Running the program
  4.12.3 Useful recipes
  4.12.4 Gauss: Format of data file
 4.13 Échelle reduction
  4.13.1 Conventional orientation
  4.13.2 Order location
  4.13.3 Order extraction
  4.13.4 Quick-look extraction using a mask
  4.13.5 Mask creation
  4.13.6 Mask extraction
  4.13.7 Accurate extraction from straightened orders
  4.13.8 Order straightening
  4.13.9 Order extraction
  4.13.10 Wavelength calibration
  4.13.11 Scrunching
  4.13.12 Merging orders
  4.13.13 Summary of the example
A Classified list of commands
 A.1 Data input
 A.2 Data output
 A.3 Display commands
 A.4 Wavelength calibration
 A.5 B-star calibration
 A.6 Arithmetic operations
 A.7 Flat fields
 A.8 Data manipulation
 A.9 Aperture photometry
 A.10 Line analysis
 A.11 S-distortion and échelle order straightening
 A.12 Fudging data
 A.13 Examining data
 A.14 Slicing through images and cubes
 A.15 Fibre data
 A.16 Flux calibration
 A.17 Extinction
 A.18 Complex data and FFTs
 A.19 Infra-red data
 A.20 Échelle data
 A.21 Spectroscopy Data Reduction (Specdre)
 A.22 Spectroscopy Data Reduction (Twodspec)
 A.23 Miscellany
B Specdre
 B.1 Introduction
 B.2 Specdre’s use of parameters
 B.3 Graphics
 B.4 Slicing data sets
 B.5 Cube manipulation
 B.6 Spectral fits
 B.7 Arc spectrum axis calibration
 B.8 References
C Twodspec
 C.1 Introduction
 C.2 Line Profile Analysis
  C.2.1 Introduction
  C.2.3 FIBDISP—Analyise 3-d Data (spectral)
 C.3 ARC2D—Wavelength Calibration
  C.3.1 Introduction
  C.3.2 Continuity Correction
  C.3.3 Evaluating the Dispersion Relation
  C.3.4 Summary of Parameters
 C.4 COMB and ARCSDI-Correction for Geometrical Distortions
  C.4.1 COMB—Correction for S-Distortion
  C.4.2 ARCSDI—Correction for Line Curvature
 C.5 Display Programs
  C.5.1 ISCAN—Plot Spectra Extracted From an Image
  C.5.2 HIMAGE—Greyscale Display
  C.5.3 CSCAN—Plot Array of Line Profiles from Data “Cube”
 C.6 Removing Continua
  C.6.1 FITCONT—Fit Polynomial to Continuum
  C.6.2 CSUB—Subtract Continuum
  C.6.3 CADD—Add Back Continuum Previously Subtracted
 C.7 Getting 3-D Data into the Correct Form for FIBDISP or LONGSLIT
  C.7.1 FIBSEP—Extract Data from Individual Fibres
  C.7.2 FIB2CUBE—Convert Fibre Data to “Cube”
 C.8 Miscellaneous Programs
  C.8.1 CUBE2LONG—Extract a Spectrum from a Spectral “Cube”
  C.8.2 VIG—Correct For Vignetting
 C.9 Note on Menus
 C.10 The Defaults File
 C.11 References
D Applications in detail
 D.1 ABCONV-Convert spectrum from Janskys into AB magnitudes
 D.2 ABLINE-Interactive absorption line analysis
 D.3 ADJOIN-Append two spectra (strictly a merge by wavelength value)
 D.4 ALASIN-Read a spectrum in ALAS (Abs. Line Analysis System) format
 D.5 ALASOUT-Output a spectrum in ALAS (Abs. Line Analysis System) format
 D.6 APERTURE-Do simple minded aperture photometry on a series of frames
 D.7 ARC-Interactive manual arc line identification
 D.8 ARC2D-Calibrates distortions in 2D arc line data.
 D.9 ARCDISP-Fit polynomial dispersion curve.
 D.10 ARCGENDB-Convert list of laboratory values to feature data base.
 D.11 ARCIDENT-Auto-identify located features.
 D.12 ARCLOCAT-Locate line features in a set of spectra.
 D.13 ARCSDI-Corrects for arc line curvature
 D.14 ASCIN-Read a 1-D or N-D data set from an ASCII table.
 D.15 ASCOUT-Write an NDF to an ASCII table.
 D.16 BBODY-Calculate a black body spectrum.
 D.17 BCLEAN-Automatic removal of bad lines and cosmic rays from CCD data
 D.18 BFFT-Takes the reverse FFT of a complex data structure
 D.19 BSMULT-Atmospheric band removal using a B star calibration spectrum
 D.20 CADD-Add back fitted continuum
 D.21 CALDIV-Generate calibration spectrum from continuum standard spectra
 D.22 CCDLIN-Applies a linearity correction to AAO CCD data
 D.23 CCUR-After SPLOT, uses graphics cursor to indicate data values
 D.24 CDIST-S-distortion correction using SDIST results
 D.25 CENTERS-Generate file of object centroids from ICUR, IGCUR or IMPOS output
 D.26 CFIT-Generate a spectrum using the cursor
 D.27 CHANGED-Indicate fits invalidated due to "cleaning" of an image
 D.28 CLEAN-Interactive patching of bad lines, bad pixels in an image
 D.29 CLIP-Clip data above and below a pair of threshold values
 D.30 CMPLX2I-Extracts the imaginary part of a complex data structure
 D.31 CMPLX2M-Extracts the modulus of a complex data structure
 D.32 CMPLX2R-Extracts the real part of a complex data structure
 D.33 CMPLXADD-Add two complex structures
 D.34 CMPLXCONJ-Produce the complex conjugate of a complex structure
 D.35 CMPLXDIV-Divide two complex structures
 D.36 CMPLXFILT-Create a mid-pass filter for complex data
 D.37 CMPLXMULT-Multiply two complex structures
 D.38 CMPLXSUB-Subtract two complex structures
 D.39 COADD-Form the spectrum which is the mean of the rows in an image
 D.40 COLOUR-Set colour table for image display
 D.41 COMB-Corrects for S-distortion using continua
 D.42 COMBINE-Combine two spectra, adding with weights according to errors
 D.43 COPOBJ-Copy an HDS object
 D.44 CORREL-Correlate two or three data sets.
 D.45 COSBELL-Create data that goes to zero at the edges in a cosine bell
 D.46 COSREJ-Reject cosmic rays from a set of supposedly identical spectra
 D.47 CREOBJ-Create a data object or file
 D.48 CRIGAUSS-Creates a file with a profile of 1 to 5 gaussians
 D.49 CSCAN-Plot array of profiles from a 3D array
 D.50 CSET-Interactively set regions of a spectrum to a constant value
 D.51 CSPIKE-Create calibration spiketrum given spiketrum and standard spectrum
 D.52 CSUB-Subtracts a continuum from 2 dimensional data
 D.53 CUBE2LONG-Takes a longslit spectrum from a non-sorted TAURUS cube
 D.54 DELOBJ-Delete a data object or a file
 D.55 DVDPLOT-Plot the data in one file against the data in another
 D.56 ECHARC-Wavelength calibrate an echelle arc
 D.57 ECHFIND-Locate spectra in echelle data
 D.58 ECHMASK-Produce an extraction mask from an SDIST analysis
 D.59 ECHMERGE-Merge echelle spectra into a single long spectrum
 D.60 ECHSELECT-Interactive selection of sky and object spectra for an echelle
 D.61 EDITEXT-Edit the Specdre Extension.
 D.62 ELSPLOT-Produces a long (<3m) error bar plot of a spectrum
 D.63 EMLT-Fits gaussians to the strongest lines in a spectrum
 D.64 ERRCON-Converts percentage error values to absolute values
 D.65 ESPLOT-Produces an error bar plot of a spectrum
 D.66 EVALFIT-Evaluate fit results.
 D.67 EXAM-Display the contents/structure of data file
 D.68 EXTIN-Correct spectrum for atmospheric extinction
 D.69 EXTLIST-Adds non-contiguous lines of an image to form a spectrum
 D.70 EXTRACT-Adds contiguous lines of an image to form a spectrum
 D.71 FET321-Extracts a spectrum from 1 detector from etalon mode FIGS data
 D.72 FF-Flat field an image (uses Jon Tonry’s algorithm)
 D.73 FFCROSS-Cross-correlate an image and a flat field (mainly IPCS data)
 D.74 FFT-Takes the forward FFT of a complex data structure
 D.75 FIB2CUBE-Arranges fibre output into 3-d data file
 D.76 FIBDISP-Fits 3D cubes and plots the results
 D.77 FIBSEP-Separate spectra in 2D array
 D.78 FIGHELP-Provide Figaro on-line help
 D.79 FIGINFO-Describes the contents of a Figaro data file
 D.80 FIGS321-Processes a FIGS data cube down to a single spectrum
 D.81 FIGS322-Processes a FIGS data cube down to an image
 D.82 FIGS422-Process a FIGS image-mode hypercube down to an image
 D.83 FIGS423-Process a FIGS image-mode hypercube down to a cube
 D.84 FIGS424-Sort a FIGS image-mode hypercube into wavelength order
 D.85 FIGSEE-Generate a seeing ripple spectrum from a FIGS spectrum
 D.86 FIGSFLUX-Flux calibrates a FIGS spectrum
 D.87 FILLCUBE-Copy one NDF into part of another.
 D.88 FINDSP-Locate fibre spectra in an image
 D.89 FITBB-Fit diluted Planck curves to a spectrum.
 D.90 FITCONT-Fits a Chebyshev polynomial to the continuum for 2D data
 D.91 FITGAUSS-Fit Gauss profiles to a spectrum.
 D.92 FITPOLY-Fit a polynomial to a spectrum.
 D.93 FITSET-Set the value of a FITS keyword
 D.94 FITSKEYS-List the FITS keywords in a data file
 D.95 FITTRI-Fit triangular profiles to a spectrum.
 D.96 FLAG2QUAL-Converts ‘flagged’ values to produce a quality array
 D.97 FLAIRCOMP-Compresses a FLAIR frame to give a weight vector.
 D.98 FLAIREXT-Optimally extracts spectra from a FLAIR NDF to form a new NDF.
 D.99 FLCONV-Convert a spectrum in Janskys into one in erg/s/cm**2/Angstrom
 D.100 FOTO-Perform aperture photometry given CENTERS output
 D.101 FSCRUNCH-Rebin data with a disjoint wavelength coverage to a linear one
 D.102 FWCONV-General unit conversion for spectra
 D.103 GAUSS-Interactive fit of Gaussians to emission or absorption lines
 D.104 GOODVAR-Replace negative, zero and bad variance values
 D.105 GROW-Copy an N-dimensional cube into part of an (N+M)-dimensional one.
 D.106 GROWX-Performs reverse function to that of EXTRACT
 D.107 GROWXT-Copies an image into contiguous XT planes of a cube
 D.108 GROWXY-Copies an image into contiguous XY planes of a cube
 D.109 GROWY-Performs reverse function to that of YSTRACT
 D.110 GROWYT-Copies an image into contiguous YT planes of a cube
 D.111 GSPIKE-Generates a ’spiketrum’ from a table of values
 D.112 HARD-Sets the file name for hard copy output
 D.113 HCROSS-Cross-correlate two spectra and get redshift and error
 D.114 HIMAGE-Creates greyscale plot of image
 D.115 HIST-Produce histogram of data value distribution in an image
 D.116 HOPT-Histogram optimization of an image
 D.117 I2CMPLX-Copies an array into the imaginary part of a complex structure
 D.118 IADD-Adds two images (or two spectra)
 D.119 IALOG-Takes the antilog of an image
 D.120 IARC-Given fit to single spectrum, fit all spectra in a 2-D arc
 D.121 ICADD-Adds a constant to an image
 D.122 ICDIV-Divides an image by a constant
 D.123 ICMULT-Multiplies an image by a constant
 D.124 ICONT-Produces a contour map of an image
 D.125 ICONV3-Convolve an image with a 3x3 convolution kernel
 D.126 ICOR16-Corrects 16 bit data from signed to unsigned range
 D.127 ICSET-Set a selected region of an image to a constant value
 D.128 ICSUB-Subtracts a constant from an image
 D.129 ICUR-Inspect an image with cursor
 D.130 IDEV-Set the device for image display
 D.131 IDIFF-Takes the ’differential’ of an image
 D.132 IDIV-Divides two images (or two spectra)
 D.133 IGCONV-Convolve an image with a specified filter
 D.134 IGCUR-Use cursor to show X, Y and data values
 D.135 IGREY-Produces a grey-scale plot of an image
 D.136 ILIST-List the data in an image (or spectrum)
 D.137 ILOG-Takes the logarithm of an image
 D.138 IMAGE-Display an image
 D.139 IMPOS-read positions from a file into environment variables
 D.140 IMULT-Multiplies two images (or two spectra)
 D.141 INTERP-Interpolates points of a ’spiketrum’ to form a spectrum
 D.142 IPLOTS-Plots successive cross-sections of an image, several to a page
 D.143 IPOWER-Raises an image to a specified power
 D.144 IRCONV-Converts data in Janskys to W/m**2/um
 D.145 IREVX-Reverse an image (or spectrum) in the X-direction
 D.146 IREVY-Reverse an image in the Y-direction
 D.147 IRFLAT-Generates a ripple spectrum from an IR spectrum
 D.148 IRFLUX-Flux calibrates an IR spectrum using a black-body model
 D.149 IROT90-Rotates an image through 90 degrees
 D.150 ISCAN-Displays cuts through an IMAGE
 D.151 ISCRUNCH-Rebin an image to linear wavelength scale given IARC results
 D.152 ISCRUNI-Like ISCRUNCH, but interpolates between two IARC result sets
 D.153 ISEDIT-Allows interactive editing of a 1-D or 2-D spectrum
 D.154 ISHIFT-Applies a linear X and a linear Y shift to an image
 D.155 ISMOOTH-2-D smooth of image using 9-point smoothing algorithm
 D.156 ISPLOT-Plots successive cross-sections through an image
 D.157 ISTAT-Provides some statistics about an image (max, min etc.)
 D.158 ISTRETCH-Stretches and shifts an image in X and Y.
 D.159 ISUB-Subtracts two images (or two spectra)
 D.160 ISUBSET-Produces a subset of an image
 D.161 ISUPER-Produces a superset of an image
 D.162 ISXADD-Adds a spectrum to each X direction X-section of an image
 D.163 ISXDIV-Divides a spectrum into each X direction x-section of an image
 D.164 ISXMUL-Multiplies each X direction image x-sect by a spectrum
 D.165 ISXSUB-Subtracts each X direction image x-sect from a spectrum
 D.166 ISYADD-Adds a spectrum to each Y direction x-section of an image
 D.167 ISYDIV-Divides a spectrum into each Y direction x-section of an image
 D.168 ISYMUL-Multiplies each Y direction image x-sect by a spectrum
 D.169 ISYSUB-Subtracts each Y direction image x-sect from a spectrum
 D.170 IXSMOOTH-Smooth in X-direction by gaussian convolution
 D.171 LINTERP-Interpolates between spiketrum points to form a spectrum
 D.172 LONGSLIT-Fits 2D longslit arrays and plots results
 D.173 LSPLOT-Hardcopy spectrum plot of specified size (up to 3 metres)
 D.174 LXSET-Set X array of spectrum/image to specified range
 D.175 LYSET-Set Y array of spectrum/image to specified range
 D.176 MASK-Generate a mask spectrum given a spectrum and a mask table
 D.177 MASKEXT-Extracts echelle orders using a mask created by ECHMASK
 D.178 MCFIT-Fit a continuum to a spectrum, given a mask spectrum
 D.179 MEDFILT-Applies a median filter to an image
 D.180 MEDFILTR-Applies a rectangular median filter to an image
 D.181 MEDSKY-Take the median of a number of images
 D.182 MOMENTS-Calculate moments of spectra in a cube.
 D.183 MOVIE-Browse through slices of a cube.
 D.184 MSPLOT-Plots a long spectrum as a series of separate plots
 D.185 NCSET-Set a region of a spectrum to a constant
 D.186 OFFDIST-Applies an offset to an SDIST fit
 D.187 OPTEXTRACT-Extracts a long-slit spectrum using Horne’s algorithm
 D.188 OVERPF-Overlays a FINDSP fit on another image
 D.189 PEAK-Determines position of highest peak in a spectrum
 D.190 POLEXT-Extract fibre spectra from an image after a FINDSP analysis
 D.191 POLYSKY-Fits and subtracts sky from a long-slit spectrum
 D.192 PROFILE-Profiles a long-slit spectrum for use by OPTEXTRACT
 D.193 Q2BAD-Converts a datafile’s quality into bad values
 D.194 QUAL2FLAG-Converts a quality array into ‘flagged’ values
 D.195 R2CMPLX-Creates a complex data structure from a real data array
 D.196 RCGS2-Reads UKIRT CGS2 spectrum (also UKT9 and UKT6 CVF)
 D.197 RDFITS-Read file in AAO de facto ’Disk FITS’ format
 D.198 RDIPSO-Read file in DIPSO/IUEDR/SPECTRUM format
 D.199 REMBAD-Removes pixels that have been flagged as bad from data
 D.200 RENOBJ-Change the name or location of an object within an HDS file
 D.201 RESAMP-Re-sample and average several spectra (was Specdre RESAMPLE).
 D.202 RESAMPLE-Rebin an image to different dimensions and/or orientation
 D.203 RESCALE-Rescale using user-defined upper and lower limits
 D.204 RETYPE-Changes the type of the main data array in a file
 D.205 ROTX-Rotate data along the X-axis
 D.206 SCLEAN-Interactive patching of images, especially SCUBA data.
 D.207 SCNSKY-Calculates a sky spectrum for a scanned CCD image
 D.208 SCROSS-Cross-correlate two spectra and get relative shift
 D.209 SCRUNCH-Rebin a spectrum to a linear wavelength range
 D.210 SDIST-Analyse an image containing spectra for S-distortion
 D.211 SETOBJ-Assign value to an HDS primitive
 D.212 SFIT-Fit a polynomial to a spectrum
 D.213 SKYLINER-Removes a sky spectrum normalised the 5577 [OI] line.
 D.214 SLICE-Takes a slice with arbitrary end points through an image
 D.215 SOFT-Sets the device/type for terminal graphics
 D.216 SPECCONT-Contour a two-dimensional cut.
 D.217 SPECGRID-Plot spectra on position grid.
 D.218 SPECPLOT-Plot a spectrum.
 D.219 SPFLUX-Applies a flux calibration spectrum to an observed spectrum
 D.220 SPIED-Interactive spiketrum editor
 D.221 SPIFIT-Fits a global polynomial to a spiketrum to form a spectrum
 D.222 SPLOT-Plots a spectrum
 D.223 SQRTERR-Generates an error array as Error = Square Root of (Data/Const)
 D.224 SUBSET-Take a subset of a data set.
 D.225 TABLE-List contents of a SPICA memory file
 D.226 TIPPEX-Modify individual pixel values with cursor
 D.227 TRIMFILE-Creates a copy of an HDS file without unused space
 D.228 VACHEL-Air to vacuum, and/or recession velocity wavelength conversion
 D.229 VIG-Corrects a 2D array for vignetting
 D.230 WDFITS-Writes an image out in the AAO de facto ’Disk FITS’ format
 D.231 WDIPSO-Writes a file in DIPSO/IUEDR/SPECTRUM format
 D.232 XCADD-Adds a constant to the X data in a file
 D.233 XCDIV-Divides the X data in a file by a constant
 D.234 XCMULT-Multiplies the X data in a file by a constant
 D.235 XCOPI-Like XCOPY but interpolates X-data from 2 files
 D.236 XCOPY-Copy X-info (e.g. wavelengths) into a spectrum
 D.237 XCSUB-Subtracts a constant from the X data in a file
 D.238 XCUR-Uses cursor to delimit part of a spectrum
 D.239 XTPLANE-Adds XT planes of a data cube to form an image
 D.240 XTRACT-Average an N-dimensional cube into an (N-M)-dimensional one.
 D.241 XYPLANE-Adds XY planes of a data cube to form an image
 D.242 YCADD-Adds a constant to the Y data in a file
 D.243 YCDIV-Divides the Y data in a file by a constant
 D.244 YCMULT-Multiplies the Y data in a file by a constant
 D.245 YCSUB-Subtracts a constant from the Y data in a file
 D.246 YSTRACT-Adds contiguous columns of an image to form a spectrum
 D.247 YTPLANE-Adds contiguous YT planes of a data cube to form an image
E Flux standards
 E.1 Spectrophotometric flux standards converted from SPICA format
 E.2 HST and new Oke spectrophotometric standard star flux tables
  E.2.1 Oke standards
  E.2.2 HST standards
F Programming
 F.1 Writing your own Figaro-style commands
G Release notes
 G.1 Changes from VAX/VMS Figaro 3.0-9 to Portable Figaro 5.1
  G.1.1 Documentation
  G.1.2 General
  G.1.3 Ported applications
  G.1.4 New applications
  G.1.5 Un-ported applications
  G.1.6 Parameters and variables: (F)PAR
  G.1.7 Data access routines: FDA
  G.1.8 Old data access routines: DSA and DTA
  G.1.9 High-level subroutines: FIG
  G.1.10 The JT-library: JTY
  G.1.11 Low-level subroutines: GEN
  G.1.12 Other libraries
 G.2 Figaro 3.1-1 release
 G.3 Figaro 3.2 release
  G.3.1 On-line help topic “News 3.2”
 G.4 Figaro 3.2-3 release
 G.5 Figaro 5.0 release
  G.5.1 Figaro 5.0-1 news item
 G.6 Figaro 5.1-3 release
 G.7 Figaro 5.1-4 release
  G.7.1 Release notes
  G.7.2 Figaro tips
  G.7.3 New Figaro features
 G.8 Figaro 5.1-6 release
  G.8.1 Release notes
  G.8.2 Figaro tips
  G.8.3 Bug fixes
 G.9 Figaro 5.2-0 release
  G.9.1 Release notes
  G.9.2 Error propagation
  G.9.3 Bug fixes
 G.10 Figaro 5.3-0 release
  G.10.1 Incorporation of SPECDRE
  G.10.2 Incorporation of IRAFFIG
  G.10.3 Minor enhancements
 G.11 Figaro 5.4-0 release
 G.12 Figaro 5.5-0 release
 G.13 Figaro 5.5-1 release
 G.14 Figaro 5.5-2 release
 G.15 Figaro 5.6-0 release
  G.15.1 Error Propagation
  G.15.2 Bug Fixes and Minor Enhancements
  G.15.3 New Application
 G.16 Figaro 5.6-1 release
  G.16.1 Bug Fixes and Minor Enhancements
  G.16.2 Flux calibration standard stars
 G.17 Figaro 5.6-2 release
 G.18 Figaro 5.6-3 release
  G.18.1 Bug Fixes and Minor Enhancements
  G.18.2 Flux Calibration Files
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