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Contents of IDL Astronomy User's Library

Astronomical Utilities

  • README
  • ADSTRING() Format RA and DEC as a character string
  • AIRTOVAC Convert air wavelengths to vacuum wavelengths
  • AITOFF Convert longitude,latitude to X,Y using Aitoff equal-area projection
  • AITOFF_GRID Create an overlay grid using the AITOFF projection
  • ALTAZ2HADEC Convert Horizon (Alt-Az) coordinates to Hour Angle and Declination
  • ARCBAR Draw an arcbar over an image showing the astronomical plate scale
  • ARROWS Given a FITS header, display a "weathervane" showing N-E orientation
  • ASTDISP Display formatter for pixel + astronomical coordinates
  • ASTRO Interactive driver to compute astronomical precession, or coordinate conversions (calls EULER and PRECESS).
  • BARYVEL Compute components of barycentric Earth velocity, given Julian date
  • BPRECESS Precess coordinates, proper motion from J2000 to B1950
  • CALZ_UNRED Deredden a galaxy spectrum using the Calzetti et al. (2000) parameterization.
  • CCM_UNRED Deredden a spectrum using the Cardelli, Clayton and Mathis (1989) parameterization.
  • CO_ABERRATION Calculate change in RA and Dec due to aberration
  • CO_NUTATE Calculate changes in RA and Dec due to nutation of the Earth's rotation
  • CO_REFRACT() Calculate correction to altitude due to atmospheric refraction
  • COSMO_PARAM Derive a full set of cosmological parameters given a subset
  • CT2LST Convert from civil time to local sidereal time
  • DATE() Convert day of year to a DY-MON-CCYY string (FITS standard)
  • DATE_CONV() Function to perform various date format conversions
  • DAYCNV Convert from Julian Date to calendar date.
  • DEREDD Deredden Stromgren indices (called by UVBYBETA)
  • ECI2GEO() Convert Earth-centered inertial coordinates to geographic coordinates
  • EQ2HOR Convert from equatorial (RA-Dec) to horizon (alt-azimuth) coordinates
  • EQPOLE Convert longitude,latitude to X,Y using polar equal-area projection
  • EQPOLE_GRID Create overlay grid using polar equal-area projection
  • EULER Astronomical coordinate system conversions
  • FLUX2MAG() Convert from flux units to magnitudes
  • FM_UNRED Deredden a spectrum using the Fitzpatrick & Massa (1998) parameterization.
  • GAL_FLAT() Correct a galaxy image for inclination effects.
  • GAL_UVW Calculate the Galactic space velocity (U,V,W) of a star
  • GALAGE() Derive a galaxy age as a function of redshift for a cosmological model
  • GCIRC Compute rigorous great circle distance
  • GEO2ECI() Convert geographic coordinates to Earth-centered inertial coordinates
  • GEO2GEODETIC() Convert from geographic to geodetic coordinates
  • GEO2MAG() Convert from geographic to geomagnetic coordinates
  • GEODETIC2GEO() Convert from geodetic to geographic coordinates
  • GET_COORDS Read in angular input in decimal or sexigesimal format
  • GET_DATE Get the current date in CCYY-MM-DD format (FITS standard)
  • GET_JULDATE Get the current Julian date as a double precision scalar
  • GLACTC Convert between Galactic (or SuperGalactic) and equatorial coordinates
  • GLACTC_PM Convert between Galactic (or SuperGalactic) and equatorial proper motion
  • HADEC2ALTAZ Convert Hour Angle and Declination to Horizon (alt-az) coordinates
  • HELIO Compute (low-precision) heliocentric coordinates of the planets
  • HELIO_JD() Convert geocentric (reduced) Julian date to heliocentric Julian date
  • HELIO_RV() Compute radial velocity given binary star orbit parameters
  • HOR2EQ Convert from horizon (altitude-azimuth) coordinates to equatorial (RA-Dec)
  • IMCONTOUR Contour plots with astronomical labeling (either RA,Dec or arc distance from the image center
  • IMF() Return values for a multi-component power law initial mass function
  • ISMEUV() Compute EUV optical depth due to photoionization of HI, HeI and HeII
  • JDCNV Convert from calendar date to Julian date.
  • JPLEPHREAD Open and read JPL DE200 or DE405 Ephemeride FITS File
  • JPLEPHINTERP Interpolate position and motion of planetary bodies (JPL Ephemeris)
  • JPRECESS Precess positions & proper motions from B1950 to J2000
  • JULDATE Convert from calendar date to reduced Julian date.
  • LSF_ROTATE Create a 1-d convolution kernel to broaden a spectrum from a rotating star
  • LUMDIST() Return luminosity distance for a given redshift & cosmological model
  • MAG2GEO() Convert from geomagnetic to geographic coordinates
  • MAG2FLUX() Convert from magnitudes to flux units
  • MONTH_CNV() Convert a month name to the equivalent number or vice-versa
  • MOONPOS Compute the RA and Dec (and distance) of the Moon at a given date
  • MPHASE Compute illuminated fraction of the Moon's disk for given Julian dates
  • NUTATE Compute the nutation in longitude and latitude for given Julian date(s)
  • OBSERVATORY Return longitude, latitude, altitude & time zones of an observatory
  • PLANCK() Returns a blackbody flux for a given effective temperature
  • PLANET_COORDS Returns low-precision coordinates of the planets
  • POSANG Compute the position angle between sources of specified RA and Dec
  • PRECESS Precess RA and Dec to a new equinox
  • PRECESS_XYZ Precess equatorial geocentric rectangular coordinates
  • PREMAT() Returns precession matrix from equinox 1 to equinox 2
  • QDCB_GRID Create overlay grid using COBE quad cube database coordinates
  • RADEC Format RA, Dec as Hours,Min,Sec,Deg,Min,Sec
  • RHOTHETA() Calculate separation and position angle of a binary star given its orbital elements
  • SIXTY Convert decimal number to sexigesimal
  • SPHDIST() Find angular distance on a sphere (in /jhuapl)
  • SUNPOS Compute the RA and Dec of the Sun at a given date
  • TDB2TDT() Relativistic clock corrections due to Earth motion in solar system
  • TEN() Convert sexigesimal number to decimal
  • TENV() Like TEN but will work on a vector of sexigesimal numbers.
  • TICPOS Specify distance between tic marks for astronomical coordinates
  • TICLABELS Create labels for astronomical coordinate tick marks
  • TICS Compute the optimum distance between tic marks for astronomical labeling
  • TIC_ONE Determine optimum position of the first tic in astronomical labeling
  • UVBYBETA Use Stromgren indices to derive dereddened colors, metallicity, and effective Temperature.
  • VACTOAIR Convert vacuum wavelengths to air wavelengths.
  • XYZ Compute heliocentric rectangular coordinates at given Julian date.
  • YMD2DN() Convert year,month,day to day number of the year (in /jhuapl)
  • YDN2MD Convert day number of the year to year, month,day
  • ZANG() Compute angular size as a function of redshift in a Friedman cosmology
  • ZENPOS Compute the RA and Dec of the local zenith at a given date

DAOPHOT-Type Photometry Procedures

  • README
  • APER Circular APERture photometry
  • CNTRD Obtain the centroid of a star by locating where derivatives go to zero
  • DAOERF Calculate the intensity, (and optionally, the derivatives) of a bivariate Gaussian, integrated over pixels. Called by DAO_VALUE
  • DAO_VALUE Obtain the value of a DAOPHOT PSF function at a given set of points
  • FIND FIND point sources within an image
  • GCNTRD Determine centroid by Gaussian fits to the marginal X,Y distributions
  • GETPSF Obtain a PSF (Gaussian + residuals) from isolated stars.
  • GROUP Place stars with non-overlapping PSF's in distinct groups
  • MMM (Mean, Median, Mode) sophisticated sky background computation
  • NSTAR Simultaneous PSF fitting of a group of stars
  • PIXWT() Compute the area of a circle-rectangle overlap (called by APER)
  • PKFIT Fit a Gaussian + residuals to a isolated star (called by GETPSF)
  • RDPSF Read a PSF file that was created by GETPSF into an IDL array.
  • RINTER Cubic Interpolation at a set of reference points, optionally obtain derivatives. (in /image)
  • SKY Compute image sky level using MMM
  • SRCOR Correlate the source positions in two different lists
  • SUBSTAR Subtract a scaled PSF at specified star positions
  • T_APER Driver procedure for APER with I/O to a disk FITS ASCII table
  • T_FIND Driver procedure for FIND with I/O to a disk FITS ASCII table
  • T_GROUP Driver procedure for GROUP with I/O to a disk FITS ASCII table
  • T_GETPSF Driver procedure for GETPSF with I/O to a disk FITS ASCII table
  • T_NSTAR Driver procedure for NSTAR with I/O to a disk FITS ASCII table
  • T_SUBSTAR Driver procedure for SUBSTAR with I/O to a disk FITS ASCII table

Database Procedures

  • README
  • DBBUILD Load or append a database with new entry values.
  • DBCIRCLE() Find entries within a specified circular area.
  • DBCLOSE Close a database
  • DBCOMPARE Display the values of two database entries side by side
  • DBCREATE Create a new database data, index and/or format file.
  • DBDELETE Delete an entry from a database
  • DBEDIT Interactively edit the entries in a database
  • DBEXT Extract items from a database into IDL variables
  • DBFIND() Find entries meeting specified criteria in an IDL database
  • DBGET() Use instead of DBFIND when search values are in an IDL vector
  • DBHELP List names of databases, or entries within a database
  • DB_INFO() Lower level routine to obtain information on an opened database
  • DBINDEX Update the IDL database index file.
  • DB_ITEM_INFO() Lower level routine to obtain information on specified item(s)
  • DB_ITEM Lower level routine to return item number and other information
  • DBMATCH() Match database entries one-to-one to specified item values
  • DBOPEN Open a IDL database
  • DBPRINT Print specified fields about specified entries in an IDL database
  • DBPUT Lower level routine to place new value for specified item into an entry
  • DBRD Lower level routine to read an entry from a database
  • DBSORT() Sort entries in an IDL database
  • DBTARGET() Find database entries within specified radius of supplied astronomical target name
  • DBUPDATE Update an IDL database with new item values.
  • DB_OR() Combine two catalog entry lists, removing duplicate values
  • DBVAL Lower level routine to extract value of specified item from an entry
  • DBXVAL Lower level routine to extract values of specified item from an entry
  • DBWRT Lower level routine to update or add a new entry to a database
  • IMDBASE Find all catalog sources within the field of an astronomical image

Disk I/O (e.g. IRAF files)

  • README
  • IRAFDIR Describe IRAF images on specified directory
  • IRAFRD Read a disk IRAF image file into IDL variables.
  • IRAFWRT Write IDL image and header to an IRAF (.pix & .imh) file
  • READ_FMR() Read a journal (ApJ, AJ) machine-readable table into IDL
  • WFPC2_READ Read a Wide Field/Planetary Camera 2 (WFPC2) image

FITS Header Astrometry

  • README
  • ADD_DISTORT Add SIP distortion parameters into a FITS header
  • AD2XY Use astrometry structure to convert celestial to pixel coordinates
  • ADXY Use FITS header to convert celestial (RA,Dec) to pixel coordinates
  • CONS_RA() Obtain the X and Y coordinates of a line of constant right ascension
  • CONS_DEC() Obtain the X and Y coordinates of a line of constant declination
  • EXTAST EXTract ASTrometry parameters from a FITS header into an IDL structure
  • FITS_CD_FIX Update obsolete representations of the CD matrix in a FITS header
  • GET_EQUINOX() Return a numeric equinox value from a FITS header
  • GETROT GET ROTation and plate scale from a FITS header
  • GSSSEXTAST Extract astrometry parameters from an STScI Survey Image
  • GSSSADXY Convert RA, Dec to pixel coordinates for an STScI survey image
  • GSSSXYAD Convert pixel coordinates to RA, Dec for an STScI survey image
  • GSSS_STDAST Insert the closest tangent projection astrometry into an STScI Guidestar Survey Image
  • HASTROM Rotate, Congrid, and/or shift an image until astrometry matches that in a reference FITS header. Used to align images.
  • HBOXAVE Boxaverage an image and update astrometry in a FITS header
  • HCONGRID CONGRID an image and update astrometry in a FITS header
  • HEULER Convert FITS WCS astrometry between celestial, Galactic and ecliptic coordinates
  • HEXTRACT Extract a subimage and update astrometry in a FITS header
  • HPRECESS Precess the astrometry in a FITS header to a new equinox.
  • HREBIN REBIN an image and update the astrometry in a FITS header
  • HREVERSE Reverse an image about either dimension and update astrometry in a FITS header
  • HROT Rotate an image and update astrometry in a FITS header.
  • HROTATE Apply IDL ROTATE function and update astrometry in a FITS header
  • MAKE_ASTR Build an astrometry structure from input parameter values
  • PRECESS_CD Precess coordinate description (CD) matrix in a FITS header to a new equinox. Called by HPRECESS
  • PUTAST Put astrometry parameters (e.g. rotation, plate scale) into a FITS header.
  • SOLVE_ASTRO Solve for an TANgent-plane astrometric plate solution with optional distortion terms
  • STARAST Obtain an exact astrometry solution given the coordinates and plate position of 2 or 3 stars.
  • TNX_EVAL() - Compute distorted coordinates give TNX (IRAF) projection
  • TPV_EVAL() - Compute distorted coordinates given TPV (Tangent + PV_ polynomial) coefficients
  • WCSSPH2XY Convert between longitude,latitude to X,Y angular coordinates for 25 different map projection types
  • UPDATE_DISTORT Update SIP astrometry coefficients for a linear transformation
  • WCSXY2SPH Inverse of WCSSPH2XY
  • WCS_CHECK_CTYPE Check that a pair of CTYPE parameters conform to WCS format
  • WCS_DEMO Demo program for WCSSPH2XY and WCSXY2SPH
  • WCS_GETPOLE Compute the coordinates of native pole for a non-polar projection
  • WCS_ROTATE Rotate between standard (e.g. celestial) and native coordinates
  • WFPC2_METRIC Compute the distortion in a WFPC2 image and return coordinates
  • XYAD Use FITS header to convert pixel (X,Y) to celestial(RA, Dec) coordinates
  • XY2AD Use astrometry structure to convert pixel to celestial coordinates
  • XYXY Convert X,Y values on one image to X,Y values in another image using astrometry in the FITS headers

STSDAS Image manipulation

  • README
  • EXTGRP Extract group parameter values and place them in a header
  • ST_DISKREAD Read an HST FITS file and reconstruct a GEIS (STSDAS) file
  • SXGINFO Return info on all group parameters in a FITS header
  • SXGPAR() Obtain group parameter values from a FITS header and parameter block
  • SXGREAD() Read group parameters from an STSDAS file
  • SXHCOPY Copy a selected portion of one header into another
  • SXHREAD Read a STSDAS header from disk
  • SXHWRITE Write a STSDAS header to disk
  • SXMAKE Make a basic STSDAS header from an IDL array
  • SXOPEN Open an STSDAS disk file for subsequent I/O
  • SXREAD() Read an STSDAS image from disk
  • SXWRITE Write an image to STSDAS format

FITS ASCII & Binary Table I/O

  • README
  • FTAB_DELROW Delete specified rows in a FITS table extension
  • FTAB_EXT Extract specified columns of a FITS table extension into IDL vectors
  • FTAB_HELP Print info about the fields in a FITS table extension
  • FTAB_PRINT Print specified columns and rows of a FITS table extension
  • FTADDCOL Add a new column to a FITS ASCII table
  • FTCREATE Create an empty FITS ASCII table header and data array
  • FTDELCOL Delete specified column from a FITS ASCII table data array
  • FTDELROW Delete specified row(s) from a FITS ASCII table data array
  • FTGET() Extract a specified field from a column in a FITS ASCII table array
  • FTHELP Display the fields in a FITS ASCII table header
  • FTHMOD Modify the attributes of a field in a FITS ASCII table
  • FTINFO Return an informational structure from a FITS ASCII table header
  • FTKEEPROW Subscript (and reorder) a FITS ASCII table array
  • FTPRINT Print specified columns and rows in a FITS ASCII table array
  • FTPUT Update or add data to a field in a FITS ASCII table array
  • FTSIZE Return the size and number of fields in a FITS ASCII table array
  • FTSORT Sort a FITS ASCII table according to the values in a specified field.
  • TBDELCOL Delete specified column from a FITS Binary table array
  • TBDELROW Delete specified row(s) from a FITS Binary table array
  • TBGET() Extract a specified field from a column in a FITS Binary table
  • TBHELP Display the fields in a FITS Binary table header
  • TBINFO Return an informational structure from a FITS Binary table header
  • TBPRINT Print specified columns and rows in a FITS Binary table array
  • TBSIZE Return the size and number of fields in a FITS Binary table array

FITS Binary Table Extensions I/O

  • README
  • FXADDPAR Add or modify a parameter in a FITS header array.
  • FXBADDCOL Adds a column to a binary table extension.
  • FXBCLOSE Close a FITS binary table extension opened for read.
  • FXBCOLNUM() Returns a binary table column number.
  • FXBCREATE Open a new binary table at the end of a FITS file.
  • FXBDIMEN() Returns the dimensions for a column in a FITS binary table.
  • FXBFIND Find column keywords in a FITS binary table header.
  • FXBFINDLUN() Find logical unit number UNIT in FXBINTABLE common block.
  • FXBFINISH Close a FITS binary table extension file opened for write.
  • FXBGROW Increase the number of rows in a binary table
  • FXBHEADER() Returns the header of an open FITS binary table.
  • FXBHELP Prints short description of columns in a FITS binary table.
  • FXBHMAKE Create basic FITS binary table extension (BINTABLE) header.
  • FXBINTABLE Common block FXBINTABLE used by "FXB" routines.
  • FXBISOPEN() Returns true if UNIT points to an open FITS binary table.
  • FXBOPEN Open binary table extension in a disk FITS file for reading
  • FXBPARSE Parse the binary table extension header.
  • FXBREAD Read a data array from a disk FITS binary table file.
  • FXBREADM Read multiple columns/rows from a FITS binary table file.
  • FXBSTATE() Returns the state of a FITS binary table.
  • FXBTDIM() Parse TDIM-like keywords.
  • FXBTFORM Returns information about FITS binary table columns.
  • FXBWRITE Write a binary data array to a disk FITS binary table file.
  • FXBWRITM Write multiple columns/rows to a FITS binary table file
  • FXFINDEND Find the end of a FITS file.
  • FXHCLEAN Removes required keywords from FITS header.
  • FXHMAKE Create a basic FITS header array.
  • FXHMODIFY Modify a FITS header in a file on disk.
  • FXHREAD Reads a FITS header from an opened disk file.
  • FXPAR() Obtain the value of a parameter in a FITS header.
  • FXPARPOS() Finds position to insert record into FITS header.
  • FXREAD Read basic FITS files.
  • FXWRITE Write a disk FITS file.

FITS I/O

  • README
  • CHECK_FITS Check that array agrees with NAXISi, BITPIX keywords of FITS header
  • FITSDIR Display info about primary FITS header(s) on disk
  • FITSRGB_to_TIFF Combine separate red, green, blue FITS files into TIFF format
  • FITS_ADD_CHECKSUM Add or update the CHECKSUM and DATASUM keywords in a FITS header
  • FITS_ASCII_ENCODE() Encode an unsigned longword as an ASCII string to insert in a FITS header
  • FITS_CLOSE Close a FITS file defined by a FITS Control Block (see FITS_OPEN)
  • FITS_HELP Summarize the primary data units and extensions in a FITS file
  • FITS_OPEN Open a FITS file and define a FITS Control Block (FCB)
  • FITS_READ Read a FITS file specified by name or FITS Control Block (FCB)
  • FITS_TEST_CHECKSUM Verify the values of the CHECKSUM and DATASUM keywords in a FITS header
  • FITS_WRITE Write a FITS primary data unit or extension
  • FITS_INFO Display info about disk FITS file(s) at a terminal or in Common
  • FXMOVE() Skip a specified number of extensions in a FITS files
  • FXPOSIT() Open a FITS file positioned to beginning of a specified extension
  • HEADFITS() Read a FITS header from a disk FITS file.
  • MKHDR Make a minimal FITS header for an image array.
  • MODFITS Modify the header or data in a FITS array (without changing the size)
  • MRDFITS() Read FITS file mapping table columns into IDL structure tags
  • MRD_HREAD Like FXHREAD but can also read a FITS header from a Unix pipe
  • MWRFITS Write a FITS file from a IDL array or structure
  • RDFITS_STRUCT Read an entire disk FITS file into an IDL structure
  • READFITS() Read a disk FITS file into an IDL data and header array.
  • SXADDHIST Add a history record to a FITS header
  • SXADDPAR Add or modify a parameter in a FITS header
  • SXDELPAR Delete a keyword from a FITS header
  • SXPAR() Obtain the value of a keyword in a FITS header
  • WRITEFITS Write IDL data and header array to a disk FITS file.

Image Manipulation

  • README
  • BOXAVE() Boxave an image, always using at least REAL*4 arithmetic
  • CONVOLVE() Convolve an image with a PSF using the product of Fourier Transforms
  • CORREL_IMAGES() Correlation of two images. Called by CORREL_OPTIMIZE
  • CORREL_OPTIMIZE Compute the optimal pixel offset of one image relative to another by maximizing the correlation function.
  • CORRMAT_ANALYZE Analyze the correlation function made by CORREL_IMAGE
  • CR_REJECT General iterative cosmic ray rejection for 2 or more images
  • DIST_CIRCLE Create a mask array useful for circular aperture photometry.
  • DIST_ELLIPSE Create a mask array useful for elliptical aperture photometry.
  • FILTER_IMAGE() Like MEDIAN or SMOOTH but handles edges & allows iteration
  • FREBIN Expand or contract an image while conserving flux
  • IMLIST Display image pixel values around a specified center
  • MAX_ENTROPY Deconvolution by Maximum Entropy, given a PSF
  • MAX_LIKELIHOOD Deconvolution by maximum likelihood, given a PSF
  • MEDARR Median filter across a set of images (e.g. for cosmic ray removal)
  • POSITIVITY() Map an image uniquely and smoothly into all positive values
  • PSF_GAUSSIAN() Create a 1-d, 2-d, or 3-d Gaussian with specified FWHM, center
  • SIGMA_FILTER() Replaces pixels deviant by more than a specified sigma from its neighbors. Useful for cosmic ray removal.
  • SKYADJ_CUBE Remove the sky level from individual images of a data cube
  • XMEDSKY Compute the median sky as a 1-d function of X (for slitless spectra)

Math and Statistics

  • README
  • AVG() Return the average value of an array or 1 dimension of an array.
  • ASINH() Return the inverse hyperbolic sine of its argument.
  • CIC Cloud In Cell interpolation of irregularly gridded data
  • CSPLINE() Interpolate using the Numerical Recipes natural cubic spline
  • FACTOR Find the prime factors of a given number (in /jhuapl)
  • FITEXY Best straight-line fit to data with errors in both coordinates
  • FLEGENDRE() Compute the first M terms in a Legendre polynomial expansion
  • GAUSSIAN() Evaluate a 1-d Gaussian and optionally its derivative
  • HERMITE() Interpolate a tabulated function using a Hermite spline
  • KSONE Compute the one-sided Kolmogorov-Smirnov statistic
  • KSTWO Compute the two-sided Kolmogorov-Smirnov statistic
  • KUIPERONE Compute the one-sided Kuiper statistic
  • KUIPERTWO Compute the two-sided Kuiper statistic
  • LINMIX_ERR Bayesian approach to linear regression with errors in both X and Y.
  • LINTERP Linearly interpolate X,Y vectors onto a new X grid
  • MEANCLIP Compute an iteratively sigma-clipped mean on a data set
  • MINF_BRACKET Find 3 points which bracket the minimum of a function
  • MINF_PARABOLIC Minimize a function using Brent's method with parabolic interpolation
  • MINF_PARABOL_D Minimize a function using a modified Brent's method which uses derivatives
  • MINF_CONJ_GRAD Find local minimum of a scalar valued function of several variables using conjugate gradient method
  • MLINMIX_ERR Bayesian approach to linear regression with errors in both X and Y and multiple independent variables.
  • MRANDOMN Generate random vectors from a multivariate normal density.
  • MULTINOM Genereate random vectors from a multinomial distribution.
  • NGP Nearest Grid Point interpolation of irregularly gridded data
  • PCA Perform a principal component analysis (Karhunen-Loeve expansion)
  • PENT() Return the information entropy S of time-series data for a set of trial periods
  • PERMUTE() Randomly permute the order of the elements in an array
  • POIDEV() Generate a Poisson random deviate
  • POLINT Polynomial interpolation of an (X,Y) pair
  • POLYLEG() Evaluate a Legendre polynomial with specified coefficients
  • POLY_SMOOTH() Apply a least-squares (Savitzky-Golay) polynomial smoothing filter
  • PROB_KS Return the significance of a Kolmogorov-Smirnov statistic
  • PROB_KUIPER Return the significance of a Kuiper statistic
  • QSIMP Integrate using Simpson's rule to specified accuracy
  • QTRAP Integrate using trapezoidal rule to specified accuracy.
  • QUADTERP Quadratic interpolation of X,Y vectors onto a new X grid
  • RANDOMCHI Generate random numbers from a chi-square density
  • RANDOMDIR Generate random vectors from a Dirichlet density.
  • RANDOMGAM Generate random numbers from a gamma distribution.
  • RANDOMP Create a vector of random numbers distributed as a power-law
  • RANDOMWISH Draw random matrices from a Wishart distribution
  • SAFE_CORRELATE() Compute the probability that data is uncorrelated while accounting for data uncertainties
  • SIXLIN Compute linear regression by 6 different methods.
  • TABINV Find the effective index of a function value.
  • TRANSFORM_COEFF Compute new polynomial coefficents under a linear transformation.
  • TRAPZD Compute Nth iteration of trapezoidal rule. Called by QSIMP, QTRAP
  • TSC Triangular Shaped Cloud interpolation of irregularly gridded data onto a regular grid
  • TSUM() Trapezoidal integration of the area under a curve
  • ZBRENT() Find the root of a function known to lie between specified limits

Plotting Procedures

  • README
  • CLEANPLOT Reset all plotting system variables to their default (X) values
  • AL_LEGEND Create an annotation legend for a plot
  • LEGENDTEST Demo program demonstrating the capabilities of AL_LEGEND
  • LINEID_PLOT Annotate the identified lines in a spectrum
  • MULTIPLOT Create multiple plots with shared axes
  • OPLOTERROR Overplot Y vs. X with optional X and Y error bars
  • PLOTERROR Plot Y vs. X with optional X and Y error bars
  • PLOTHIST Plot the histogram of an array
  • PLOTSYM Define useful plotting symbols not in the standard PSYM definition
  • PARTVELVEC Plot the velocity vectors of a set of particles
  • RDPLOT Like intrinsic CURSOR procedure but with a full-screen cursor
  • SUNSYMBOL() Return the character string to plot a subscripted Sun symbol
  • VSYM Create "Mongo"-like rotationally symmetric polygon plotting symbols

IDL Structure procedures

Robust Statistics

Web Socket Procedures

  • README
  • QUERYDSS Query the digital sky survey (DSS) on-line at the European Space Observatory (ESO) or STSCI servers
  • QUERYGSC() Query the Guide Star Catalog (GSC V2.3.2) at the Space Telescope Science Institute by position
  • QUERYSIMBAD Query the SIMBAD or NED name resolver to obtain J2000 coordinates
  • QUERYVIZIER() Query any catalog in the VIZIER database by position
  • QUERY_IRSA_CAT() Query IRSA catalogs, returning an IDL structure
  • READ_IPAC_TABLE() Read an IPAC Table file into an IDL structure
  • READ_IPAC_VAR() Convert an internal IPAC variable to an IDL structure
  • WRITE_IPAC_TABLE Write an IDL structure to an IPAC Table file
  • WEBGET() Use the IDL SOCKET procedure to get data from http servers

TV Display Procedures

  • README
  • BLINK Blink two or more windows in an image display
  • CURS Change the shape of the (X windows only) cursor
  • CURVAL Interactive display of image intensities and astronomical coordinates
  • PIXCOLOR Set specified pixel values to a specified color
  • SIGRANGE() Find range of pixel values which contain 90% of the image values
  • TVBOX Draw a box of specified size on the image display
  • TVCIRCLE Draw a circle of specified radius on the image display
  • TVELLIPSE Draw an ellipse of specified axes on the image display
  • TVLASER Write an image to postscript file with annotation from a FITS header
  • TVLIST Display intensity values surrounding the cursor position
  • UNZOOM_XY Convert from window coordinates to image coordinates
  • ZOOM_XY Convert from image coordinates to window coordinates

Miscellaneous (Non-Astronomy) Procedures

  • README
  • ASTROLIB Add the non-standard system variables used in the IDL Astronomy User's Library
  • BLKSHIFT Shift a block of data to a new (possibly overlapping) position in a file
  • BOOST_ARRAY Append one array onto another, adjusting dimensions if necessary
  • BREAK_PATH() break up a !PATH-like string into individual directories
  • BSORT() Like the IDL SORT function but subscript order is maintained when value are equal -- like a bubble sort.
  • CHECKSUM32 Compute the 32bit checksum of an array (ones-complement arithmetic)
  • CIRRANGE Force an angle to be in the range 0 to 360 (or 0 to 2*!PI).
  • CONCAT_DIR concatenate directory and file name for current OS
  • DELVARX Delete an IDL variable; like DELVAR but works at any calling level
  • DETABIFY() Replace tabs in a character string by equivalent number of spaces
  • EXPAND_TILDE() Expand tilde in UNIX directory names
  • F_FORMAT() Find the "best" F format to display an array of REAL*4 numbers.
  • FDECOMP Decompose a file name (Disk + Directory + Name + Extension + Version)
  • FINDPRO Find all occurrences of a procedure in one's !PATH
  • FIND_ALL_DIR Find all directories under a specified directory
  • FIND_WITH_DEF Search for files with default path and extension
  • FORPRINT Print a set of vectors by looping over each index value
  • GETOPT() Parse a user supplied string into numeric value(s).
  • GET_PIPE_FILESIZE Determine the number of bytes in a unit opened as a pipe with SPAWN Parse a user supplied string into numeric value(s).
  • GETPRO Search !PATH directory for a procedure and copy into user's directory
  • GETTOK() Extract a string up to a specified character.
  • GETWRD() Get specified item (word) from a string (in /jhuapl)
  • HGREP Find a substring in a FITS header or other string array
  • HOST_TO_IEEE Convert IDL variable from host machine bit order to IEEE
  • HPRINT Pretty terminal display of a FITS header (or other string array)
  • IEEE_TO_HOST Convert IDL variable from IEEE bit order to host machine
  • ISARRAY() Determine if an IDL variable is an array (in /jhuapl)
  • IS_IEEE_BIG() Determine if the host machine is IEEE big endian
  • LIST_WITH_PATH() Search for files within specified directory path
  • MAKE_2D Change from 1-D indexing to 2-D indexing
  • MATCH Find the subscripts where the values of two vectors match.
  • MRD_SKIP Skip a number of bytes from current location in a file or a Unix pipe
  • MINMAX() Return the min and max of an array in an 2 element vector
  • N_BYTES() Return the number of bytes in an IDL variable
  • NINT() Like intrinsic ROUND() function but returns integer instead of long
  • NULLTRIM() Delete all characters after, and including, the the first null byte(0). Called by TAB_PUT.
  • ONE_ARROW Draw an arrow labeled with a single character
  • ONE_RAY Draw a ray by specifying starting point, angle, and length
  • ORDINAL() Return the English equivalent of ordinal numbers, i.e. '1st','2nd'
  • OSFCNVRT() Format the input as a logical name in the host operating system
  • POLREC Convert from polar to rectangular coordinates (in /jhuapl)
  • QGET_STRING() Read a string (eg. password) from the keyboard without echoing it
  • RDFLOAT Quickly read an ASCII file with columns of data into IDL vectors
  • READCOL Read a file of free-format ASCII data into IDL vectors
  • READFMT Quickly read a file of fixed-format ASCII data into IDL vectors
  • READ_KEY() Like GET_KBRD but returns a code for escape sequences.
  • RECPOL Convert from rectangular to polar coordinates (in /jhuapl)
  • REMCHAR Remove all appearances of a character from a string.
  • REM_DUP() Remove duplicate values from a vector.
  • REMOVE Contract a vector or up to 8 vectors by removing specified elements
  • REPCHR() Replace all occurrences of one character by another (in /jhuapl)
  • REPSTR() Replace all occurrences of one substring in a string by another.
  • SELECT_W Allow user to interactively select from a list of strings
  • SPEC_DIR() Complete specification of a file name using default disk & directory
  • STORE_ARRAY Insert one array into another, adjusting dimensions if necessary
  • STRCOMPRESS2() Remove blanks around specified characters in a string
  • STRN() Convert a number to a string and remove padded blanks.
  • STRNUMBER() Determine whether a string is a valid numeric value.
  • TEXTOPEN Open a file for text output as specified by TEXTOUT keyword
  • TEXTCLOSE Close a file that had been opened by TEXTOPEN.
  • TO_HEX() Translate a non-negative decimal integer to a hexadecimal string
  • VALID_NUM() Determine if a string is a valid number (cf. STRNUMBER)
  • VECT() Display a set of numbers to a string with delimiters
  • WHERENAN() Find points equal to big-endian IEEE NaN (not a number) values
  • XDISPSTR Widget display of a string array with a simple search facility
  • ZPARCHECK Check the type and size of a parameter


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NASA Official: Theodore Gull
Last Updated: Jul-2014