SDSS Library

The following is a listing of the entire contents of this library for IDL. Click on an individual procedure name to view its header and source code. This listing is a shortened form of the much longer entire library help file. This may be handy for text searchs, be beware that some of these are huge and may take a long time to load or even crash your browser.

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List of Routines

• ADD_ARRVAL Add an element to an array "array". If input array is undefined, set it equal to the new value.
• ADD_TAG Add a new tag to the structure. NOTE: if you want to add more than one tag at once, use ADD_TAGS
• ADD_TAGS Add new tags to the structure. Similar to add_tag, but with these major differences: --Unlike the program ADD_TAG, ADD_TAGS can add multiple new tags. --Unlike add_tag, which takes an actual value for the new tag, ADD_TAGS takes in string indicators for each new tag, such as 'fltarr(3)', or '10', and uses MRD_STRUCT --Because of this, ADD_TAGS cannot add specific values for non-scalars.
• ANGDIST calculate angular diameter distance between zmin and zmax Currently only works for lambda = 0 universe.
• ANGDIST_LAMBDA calculate angular diameter from zmin to zmax in flat lambda universe Uses 4th order polynomial approximation see Pen, U., 1999, ApJ Supplement, 20, 49. For z between 0.2 and 1.0 the error is about .4% (Exact for omega_matter = 1.0)
• APLOT Wrapper for PLOT that forces a user defined aspect ratio.
• APLOTERROR Wrapper for PLOTERR that forces a user defined aspect ratio.
• ARRSCL Rescale the range of an array.
• ASTRONOMYIMAGE__DEFINE[10] This method returns a vector storing the size of the image.
• ASTRONOMYIMAGE__DEFINE[11] This method returns a the value of a keyword in the header
• ASTRONOMYIMAGE__DEFINE[12] This method deletes a line from the header
• ASTRONOMYIMAGE__DEFINE[13] This method adds a line from the header
• ASTRONOMYIMAGE__DEFINE[14] This method replaces a line from the header
• ASTRONOMYIMAGE__DEFINE[15] This routine provides the deffinition of the astronomyImage object. This object is not intended to be used in practice; under most circumstances, one of it children (dataImage or maskImage) probably provides more functionality.
• ASTRONOMYIMAGE__DEFINE[1] CLASS_NAME: astronomyImage PURPORSE: astronomyImage is intended to be a superclass of classes used store image used for astronomical applications. SUPERCLASSES:
• ASTRONOMYIMAGE__DEFINE[2] This method creates a duplicate image object. If no temporary file name is provided, the data for the new image is stored in
• ASTRONOMYIMAGE__DEFINE[2] Clean up the memory used by the image object. In particular, free the data and header memory
• ASTRONOMYIMAGE__DEFINE[3] The method is used to return an array with the image data.
• ASTRONOMYIMAGE__DEFINE[4] If the image data is currently stored in a file, this method loads the data into memory and destroys the file. Otherwise, it has no effect.
• ASTRONOMYIMAGE__DEFINE[5] This method load an image from disk into the image object.
• ASTRONOMYIMAGE__DEFINE[6] This method resizes the image.
• ASTRONOMYIMAGE__DEFINE[7] This method saves the data array to a temporary disk file, and uses an array associated with this file to store this data. See the IDL documentation on associated variables (the ASSOC function) for more information about how this works.
• ASTRONOMYIMAGE__DEFINE[8] This method saves the image object.
• ASTRONOMYIMAGE__DEFINE[9] This method sets the data of the image object.
• ATLAS_NAME Subroutine of get_atlas. Creates the name of atlas file.
• BEGPLOT This procedure redirects plots from the present display/ graphics device to another display/graphics device. It is a 'macro' to the SET_PLOT and DEVICE graphics routines. At this time only the 'PS' device is fully supported. See also KILLPLOT and ENDPLOT. CATEGORY:
• BINARY_SEARCH Perform a binary search on arr, an input array, for the closest match
• BTC_EXTRACT Run sextractor on an image using the parameters passed in param_struct
• BTC_EXTRACT_SETUP Set up a parameter structure for sextractor operation on btc data
• CIRC_RADEC Circles an ra and dec position on the input image. We need a photo structure, an index and the position of the object with that index inorder to complete the mapping.
• CLOSE_MATCH this will find close matches between 2 sets of points (t1,s1) and (t2,s2) (note t1,t2,s1,s2 are all arrays) in a 2 dimentional space. differnt then close_match in that it gives the 'allow' CLOSEST matches
• CLOSE_MATCH_RADEC this will find close matches between 2 sets of points (t1,s1) and (t2,s2) (note t1,t2,s1,s2 are all arrays) in ra dec space.
• COMBINE_ATLAS Subroutine of get_atlas. Combines images
• COMBINE_STRUCTS takes two arrays of structures str1,str2 which have the same number of elements but possibly different tags and makes another structure which has the same number of elements but the tags of both str1,str2 and has their respective tags values copied into it
• COMPUTE_SEP compute the seperation in arc seconds and position angle between an objects two children if it has two children position angle is an angle between 0 degrees and 180 degrees
• CONCAT_DSTRUCTS Concatenate two possibly DIFFERENT structures that have common tags but not necessarily identical tags.
• CONCAT_STRUCTS for concatenating two arrays of structures of the same type but not necessarily the same name or order of tag names.
• CONVERT2RD Convert from x-y to ra and dec
• CONVERT2XY Convert from ra and dec to x-y
• COPY_ATLAS Subroutine of get_atlas.
• DATAIMAGE::ANGLE This method replaces the data with an image where each pixel has the theta value of that pixels polar coordinate, where the origin is at the specified coordinate. Together with the dataImage::radius method, it can be used to get the polar coordinates of each pixel.
• DATAIMAGE::BUTTERWORTHFILTER This method applies a Butterworth filter to the image.
• DATAIMAGE::CENTER This method moves the center (or some specified coordinate) to the corner of the image. This is particularly useful for working with PSF images.
• DATAIMAGE::CLONE This method creates a duplicate image object. If no temporary file name is provided, the data for the new image is stored in
• DATAIMAGE::COPY This method is identical to the dataImage::clone method
• DATAIMAGE::ELLIPSESPACE This method creates a model of the galaxy using fits in (intensity, radius, angle) space. The center of the galaxy must be provided. This method works well for elliptical galaxies where the center of the isophotes varies little with the intensity of the isophote.
• DATAIMAGE::ESTIMATEK This uses a power spectrum fit to esitmate k, the parameter of the Wiener filter.
• DATAIMAGE::ESTIMATESIGMA This method estimates the sky sigma using the pixels with low pixel values. It only provides meaningful results where the sky and diffuse background objects have been subtracted.
• DATAIMAGE::EXPONENTIALFIT Fit in exponential profile to a section of an image of a galaxy, and return the best fits.
• DATAIMAGE::FOURIERTRANSFORM This method replaces the data associated with an image with it fourier transform
• DATAIMAGE::FREQUENCYFILTER This method replaces the data with the data passed through a fourier frequency filter.
• DATAIMAGE::GETDATA This methods returns an array containing the image data, optionally scaled to a provided exposure time, or for display.
• DATAIMAGE::GETPROPERTY This method gets some of the properties of the data image.
• DATAIMAGE::IDEALFILTER This method applies an ideal filter to the image.
• DATAIMAGE::LOAD This method load an image from disk into the image object.
• DATAIMAGE::NORMALIZE This method normalizes the total flux of the image to a set value. This is particularly useful for normalizing PSF images
• DATAIMAGE::PIXELWAVENUMBER Returns an array, where the value of each pixel corresponds to the wavenumber represented by that pixel in a fourier transformed image.
• DATAIMAGE::POWERSPECTRUM This method replaces the image data by its power spectrum.
• DATAIMAGE::PSFFILTER Frequency filters the image to emphasize point sources. It is intended to emphasize point source in front of extended sources, such as galaxies. If the galaxy has a bright, point source like center, it is often helpful to smooth it out before the appliation of this filter.
• DATAIMAGE::PSPECFIT Fit the power spectrum of the image to a linear function of the power spectrum of the PSF. This is primarily useful for separation of surface brightness fluctuation (SBF) variance from noise variance.
• DATAIMAGE::RADIUS This method replaces the data with an image where each pixel contains the distance of that pixel to a specified coordinate. It may be used, for exampled, to get distances from the center
• DATAIMAGE::RESIZE This method resizes the image. It does not change the pixel scale; it merely cuts off or pads the image to make it the
• DATAIMAGE::SEGMENT Segment the data image. Pixels above the segmentation value are set to one, and those below it are set to zero. Often, one would want to use the maskImage::segment instead.
• DATAIMAGE::SETPROPERTY This method sets the properties of the data image.
• DATAIMAGE::TRIANGULATE This method replaces masked pixels with values calculated using triangulation from nearby food pixels.
• DATAIMAGE::WIENERFILTER This method replaces the method by a Wiener filtered version of the image. For information on using a Wiener filter, consult a image processing reference guide, _Digital Image Processing_ by Gonzales & Woods (1992), or _The Image Processing Handbook_ by Russ (1995).
• DATAIMAGE__DEFINE This routing defines the dataImage object. The dataImage object is intended to be the primary object used to store and manipulate astronomical image.
• DCENTER Center up the display
• DISPLAY_ATLAS Subroutine of get_atlas. Displays image.
• DISPLAY_FCHART display a photo finding chart and circle the object that was used to make the chart. Label axis with arcminutes from the center.
• ENDPLOT Closes and saves the current plotfile. By default, the file is then spooled to the printer using the unix 'lpr -r' command. Keywords are available to name the plotfile and inhibit spooling. See also BEGPLOT and KILLPLOT. CATEGORY:
• EQ2SURVEY Convert from ra, dec to lambda, eta (SDSS survey coordinates)
• ETA2STRIPENUM Find which stripe goes with this eta.
• EXIST A very simple check to see if a file exists...
• EXTRACT_GALAXIES Extracts a clean set of galaxies
• EXTRACT_STARS Extracts a clean set of stars suitable for PSF determination
• FCHART FCHART PURPOSE: Create a finding chart for the object in index. CALLING SEQUENCE: fchart, pstruct, index, radius, clr, fchart, dir=dir, silent=silent, objx=objx, objy=objy, nonoise=nonoise
• FCHART_CIRC_RADEC Build a finding chart and (unless requested otherwise ) circle positions in ra and dec arrays.
• FETCH_DIR given run camcol and rerun it will retrun the directory dir on fsgi03 where this tsObj file lives and the directory atldir where the atlas images live if given the field it will output the tsObj file as well and the atlas file
• FETCH_FILE_LIST for use with read_tsObj will return the list of tsObj files in directory dir (the new field-seperarted tsObj files) between start and start+nframe Can also have a front other than tsObj if so desired, but must have form front-run-camcol-rerun-field.extension
• FETCH_RERUN will get the newest rerun that exists on disk for run "run" does this by CD-ing to the directory from '/usr/sdss/data01/imaging/'+string(run)+'/calibChunks/' this directory is symbolically linked to the newest rerun directory. Then just spawn a pwd and look at the directory name
• FIELD2STRING Function outputs a string containing field of a photo tsObj file in the correct format.
• FINDABTHETA find the axis ratio and position angle of an object with e1 and e2 as ellipticity parameters. Currently only works for unweighted or adaptively weighted moments.
• FINDE Find the e1 and for a perfectly elliptal object with the given axis ratio. e1_ad and e2_ad are for unweighted or adaptively weighted moments. e1_lup and e2_lup are Robert Luptons q and u which are in SDSS PHOTO catalogs.
• FIND_RADEC Find the run, camcol and field that contain the input ra and dec. More than one run may be returned if ra,dec is in overlap region between the runs.
• FIND_RADEC_FCHART Create a finding chart for the input coordinates.
• FLAG_SELECT Makes cuts based on flag structure. These cuts are strictly "anded" together, so they must all be true for the object to survive.
• FXPOSIT2 Return the unit number of a file positioned to the beginning of a particular extension.
• GC2EQ convert from great circle to equatorial coordinates
• GC2SURVEY convert from SDSS great circle to SDSS survey coordinates
• GENRAND output random numbers from probability function
• GETUNIQ get the unique elements from an array.
• GET_ATLAS Grab the atlas images for a list of objects.
• GET_FAMILY retrieves atlas images for an object and any other objects associated with it in a blend.
• GOOD_RERUNS Find the rerun for runs in the !SDSS_DATA_DIR, and see if there are any tsObj files there.
• HEADER_BLOCK This is a template for procedure headers.
• HIST2D like the IDL built in function hist_2d but better since it can accept floats output histogram is a longarray(nxbins,nybins) uses only the relevent data in range
• HISTOGRAM_2D takes two dimentional data x,y and makes a histogram, hist,with hist_2d. hist is a structure that also contains the scaling parameters so one can display it with the right x,y, scale etc.
• INTFUNC Make a cumulative integral function. Basically just tabulate the integral up to each xi
• IRCAMIMAGE__DEFINE[10] Overplot a location, expressed in R. A. and declination on a cloud camera image
• IRCAMIMAGE__DEFINE[11] Overplot the position of the moon
• IRCAMIMAGE__DEFINE[12] Overplot the position from a fits header
• IRCAMIMAGE__DEFINE[13] Return whether some part of an image exposure occurred during some part of a cloud scan.
• IRCAMIMAGE__DEFINE[14] Return an array of filenames containing the images contemporary to the scan
• IRCAMIMAGE__DEFINE[15] Set the quality keywords in the headers of contemporary images
• IRCAMIMAGE__DEFINE[16] Return an array of filenames containing the images contemporary to the scan
• IRCAMIMAGE__DEFINE[17] This procedure loads the first scan contemporary with a supplied image
• IRCAMIMAGE__DEFINE[18] Overplot the position of the sun
• IRCAMIMAGE__DEFINE[19] do a quick analytical flattening of an ircam image
• IRCAMIMAGE__DEFINE[1] An ircamImage object consists of an image from the APO 10 micron all sky camera. The class methods provide tools for examining such images.
• IRCAMIMAGE__DEFINE[20] Find the median of neighboring (in time) images
• IRCAMIMAGE__DEFINE[21] Replace the data in the object with the median of neightbors
• IRCAMIMAGE__DEFINE[22] Subtract an image from the ircam image
• IRCAMIMAGE__DEFINE[23] This routine defines the structure for an ircamImage object
• IRCAMIMAGE__DEFINE[2] This method sets the value for a property or group of properties for the ircamImage object
• IRCAMIMAGE__DEFINE[2] The ircamImage::Init function method initializes the ircamImage object
• IRCAMIMAGE__DEFINE[3] This method gets the value for a property or group of properties for the ircamImage object
• IRCAMIMAGE__DEFINE[4] This method load an ircam image from disk into the image object.
• IRCAMIMAGE__DEFINE[5] This method returns true if the filename appears to be in the standard YYMMDD.HHMM format, false otherwise. Some extensions (.fit, .fit.gz, .fit.Z, etc.) do not disqualify it.
• IRCAMIMAGE__DEFINE[6] This method estimates a good display range for viewing the image.
• IRCAMIMAGE__DEFINE[7] Display the image, nicely scaled. Note that it is a good idea to use either the WINDOW or ZDISPLAY keywords, or otherwise ensure that the plotting devise has the correct size. If it does not, then overplotted points will not be positioned
• IRCAMIMAGE__DEFINE[8] Overplot a location, expressed in aximuth & altitude, on a cloud camera image
• IRCAMIMAGE__DEFINE[9] Overplot a location, expressed in hour angle and declination, on a cloud camera image
• KMAP this maps (xin,yin) to (xout,yout) with the transformation kx,ky that were presumably found with polywarp the formula is (summation over i,j) xout=(kx)ij * xin^j * yin^i yout=(ky)ij * xin^j * yin^i hence the two matrices kx and ky hold all the transformation coefficients
• KMAP_INV this find the inverse map for kx and ky (any order) and applies it to x2,y2 to output x,y note that kx,ky does not in general have an inverse this procedure only works when the the map kx,ky is approximately a nonsingular linear transformation ie. the higher order terms do not dominate the map it works by first linearizing the map and finding the inverse matrix and using this to generate the approximate inverse map range (ie. the domain for kx,ky) using this range it maps test points to the x2,y2 neighborhood
• LUMDIST calculate luminosity distance Currently only works for lambda = 0 universe. See angdist_lambda.
• MAKEGAUSS make an array with values set to a gaussian Dave J. My changes E.S.S.
• MAKE_COLOR_FLAG takes the str from search color_space and sets the flag depending on whether the object lies in that region of color space (and size-mag space) flag values are anded together they range from 0 to 15 (four different bits may be set depending on whether that object is in each region) objects in all four regions have flag=15
• MAKE_DEFAULT_TAGS Produces a list of photo tags. Can be sent to READ_PHOTO_COL or
• MAKE_DEVAUC Dave Johnston's code. My Changes. E.S.S. This code makes de Vaucouleurs intensity profile, used for elliptal galaxies
• MAKE_EXP make an array with values set to an ellitical exponential.
• MAKE_FLAG_STRUCT Set up a parameter structure for sdss flag selection Can select on either flags or flags2.
• MAKE_GAUSSIAN make an array with a gaussian in it
• MAKE_STATUS_STRUCT Set up a parameter structure for sdss status selection
• MAKE_TSFLAG_STRUCT Set up a parameter structure for sdss target flag selection.
• MASKIMAGE::ASYMMETRY Thie method returns an array of the asymmetries of the masked pixel regions in a supplied data image.
• MASKIMAGE::CENTER Thie method returns an array of the center of flux in masked pixel regions, in x and y pixel coordinates..
• MASKIMAGE::CLOSE This method performs an closeing operation on the mask.
• MASKIMAGE::DILATE This method performs a dilation operation on the mask.
• MASKIMAGE::ERODE This method performs an erosion operation on the mask.
• MASKIMAGE::FRACTION This function returns the fraction of unmasked pixels in the mask.
• MASKIMAGE::GETDATA This methods returns an array containing the image data.
• MASKIMAGE::GETPROPERTY This method gets some of the properties of the data image.
• MASKIMAGE::INVERT This method inverts the sence of the mask: unmasked pixels become masked, masked pixels become unmasked.
• MASKIMAGE::KINGPARAMETERS This method fits King profile models to the pixels in a data image which correspond to masked regions in the mask image. It was designed for measureing globular cluster parameters from an image using a mask covering the globular
• MASKIMAGE::LUMINOSITY To return the flux in pixel regions in a dataImage which correspond to the regions of masked pixels in the mask.
• MASKIMAGE::MAXSIZE This method removes masked regions greater than a specified size from the mask.
• MASKIMAGE::MINCORERADIUS This method unmasks regions where the core radius of the best fit globular cluster to the pixels in a data image corresponding to the region is smaller than some threshhold. The primary purpose of this method is to unmask cosmic rays, hot pixels, and possibly foreground stars in masks of candidate objects.
• MASKIMAGE::MINLUMINOSITY This method unmasks regions where the total flux in the corresponding pixels in a data image are below a specified
• MASKIMAGE::MINRADIALMOMENT This method unmasks regions where first radial moment of the corresponding pixels in a data image is below a specified
• MASKIMAGE::MINSIZE This method removes masked regions smaller than a specified size from the mask.
• MASKIMAGE::MOMENT2 This metbod returns the second order moments of masked objects in a supplied dataImage image.
• MASKIMAGE::OBJECTSIZE Thie method returns an array of the sizes of the masked regions, in pixels.
• MASKIMAGE::OPEN This method performs an opening operation on the mask.
• MASKIMAGE::POSITIONMASK This method sets the data to a mask created using a cutoff in the the value in a function of x and y.
• MASKIMAGE::RADIALMOMENT Thie method returns an array of the radialMoments of the masked pixel regions in a supplied data image.
• MASKIMAGE::SEGMENT This method replaces the data in the mask with a segmentation of the data image provided as an argument.
• MASKIMAGE::SETPROPERTY This method sets the properties of the mask image.
• MASKIMAGE__DEFINE This procedure defines the maskImage object. The maskImage object is inteded to be used for two level images, particularly where the nonzero level indicates something about the corresponding pixel in a dataImage object.
• MATCHPHOTO match two photo structures by id and field. !!!! Use PHOTO_MATCH its much faster.
• MFACT find the factorial of each element in an array.
• MISSING_ATLAS Called by get_atlas figure out what to do if an atlas image is not found.
• MRDFITS3 Read all standard FITS data types into arrays or structures. Further information on MRDFITS is available at http://idlastro.gsfc.nasa.gov/mrdfits.html
• NTOSTR convert a number to a string. Cuts off white spaces.
• OBJ_INFO For a list of objects (index) make color-color diagrams, size vs brightness plot, find its family, and make its own FINDING CHART.
• PHOTOMAP map ra and dec to row and col. The map centers on the first ra-dec position in the lists. NOTE: If clr is not given, then the program uses RED (clr=2) to find the map.
• PHOTO_MATCH Match to lists of photo objects by their run, rerun, camcol, field, and rerun. This uniquely defines each object.
• PLOTH histogram first and displays that as an image with tvim2 and returns a histogram structure
• PLOTHIST2 Plot the histogram of an array with the corresponding abcissa.
• PLOT_1COLOR make color-color plot from sloan colors. Plot one set of data from obj_struct. Over plot, if requested, from oplot_str
• PLOT_COLORS make color-color plots from sloan colors. Plot one set of data from obj_struct. Over plot, if requested, from oplot_str.
• PLOT_FLAGS Plots flags for a set of objects
• PLOT_TSFLAGS Plots target selection flags for a set of objects
• PRETTYPT This routine builds a "pretty picture" from SDSS PT images using the files produced by mtFrames.
• PRINT_FLAGS Prints flags for a single object....
• PRINT_TSFLAGS Prints target selection flags for a single object
• PTIME print a time in a hr min sec format.
• QU2E Convert Robert Luptons q and u shape parameters to ellipticity parameters as measured by unweighted moments and Gary Bernstein's adaptive moments.
• RADECSTR Wrapper for radec. Returns string versions of ra and dec.
• RADEC_MATCH RADEC_MATCH CALLING SEQUENCE: radec_match.pro,m1,m2,newmatch m1: first match structure m2: second match structure OUTPUTS: newmatch: combined structure, merged on (ra,dec)
• RD2XY Compute an X and Y position given the RA and DEC and an astrometry structure from a FITS header. A tangent (gnomonic) projection is computed directly; other projections are computed using WCSXY2SPH. AD2XY is meant to be used internal to other procedures. For interactive purposes, use ADXY.
• RDIS Wrapper for tvim2. One can zoom, rescale, flip across x or y, or rotate by 180 degrees.
• RDIS_SETUP Set up a parameter structure for rdis
• RDIS_ZOOM Allows zooming in rdis
• RDYANNY Read in a minimal Brian Yanny parameter file. The file must have only one structure definition and one set of data.
• READ_ASTRANS Read from an asTrans astrometry transformation file for given run, camcol, and bandpass. Can be used to transform between (row,col), or CCD coordinates, and (mu,nu), or great circle coords.
• READ_PHOTO_COL Reads part of a column of SDSS data into one big struct.
• READ_TSOBJ Reads in a column of SDSS data into one big struct. A rewritten version of read_photo_col that reads the newer individually wrapped tsObj files
• READ_TSOBJ_MAKE_STRUCT Creates a structure with the user's input parameters.
• READ_TSOBJ_MAKE_TAGS Finds all input tags that match with photo tags and puts them into goodtags
• REMOVE_TAGS remove the specified tags from input structure
• REXTRACT Run sextractor on an image using the parameters passed in param_struct
• REXTRACT_SETUP Set up a parameter structure for sextractor operation
• RGBVIEW Create and display a RGB image from red, green, and blue input images.
• RMDEGEN remove the denerate values from an array. Return an array or indices containing only 1 of each value in array. THIS PROGRAM IS SLOW. Use rem_dup of idlastron library.
• ROWCOL2MUNU convert from row-column to great circle coordinates (mu,nu)
• RUN2STRING Function outputs a string containing run of a photo tsObj file in the correct format.
• SAO Call saoimage externally. You should modify this if your saoimage is not aliased to sao
• SDSSIDL_SETUP Define system variables used by sdssidl procedures.
• SDSS_EXTRACT SDSS_EXTRACT Applies a user defined extraction function to an SDSS column.... INPUTS: filename: name of input fits file ofilename: output fits file (will overwrite existing file) command_name: command to use for extraction
• SEARCH_COLOR_SPACE For taking an sdss catalog and selecting objects of desired colors,magnitude and size. Does this by plotting four plots. u-g versus g-r g-r versus r-i r-i versus i-z r versus petrorad(in r color) Then it prompts you to draw a closed curve on all four plots. Then it makes a structure with this information stored in it. The structure and a photo catalog can be handed to make_color_flag which will then flag each objects with a number 0 to 15
• SELECT_COLORS An interactive tool for selection sdss objects based on their colors , magnitudes and size. It will make the following four plots: u-g versus g-r g-r versus r-i r-i versus i-z r versus petrorad(in r color) Then it prompts you to draw an arbitrary closed curve on all four plots. From these curves it selects the objects having parameters contained in all four regions and outputs their index.
• SIGMA_CLIP a simple sigma clipping algoritm
• SIMPCTABLE Create and load a simple 8-color color table
• SKYFUNCTION skyFunction PURPORSE: This function estimates the shape of the sky, and is used in the ircamImage object. Designed to be used in the standard IDL routine curvefit. MODIFICATION HISTORY:
• STATUS_SELECT Makes cuts based on status structure. These cuts are strictly "anded" together, so they must all be true for the object to survive.
• SURVEY2EQ Convert from lambda, eta (SDSS survey coordinates) to ra, dec
• TAG_TYPE Finds the type of an input tag
• TMPFILE TMPFILE CALLING SEQUENCE: s = tmpfile(prefix=prefix, suffix=suffix) Returns a unique filename for scratch use. Ex: myfile = tmpfile(prefix='/tmp/', suffix='.tmp')
• TSFLAG_SELECT Makes cuts based on flag structure. These cuts are strictly "anded" together, so they must all be true for the object to survive.
• TSOBJ_NAME ouputs the filename for a photo tsObj file for the given input
• TVIM2 USEAGE: tvim2,a tvim2,a,title=title,xtitle=xtitle,ytitle=ytitle,$ xrange=xrange,yrange=yrange,subtitle=subtitle,$ scale=scale,range=range,noframe=noframe,aspect PURPOSE: Display an image with provisions for
• TVIM2_SCL To view a peice of an image and retain the coordinates of the original image in that peice
• WHICH Determine in which library/directory the procedure or function specified is located in the !PATH. This is useful for finding out which library a certain procedure comes from, particularly when there are duplicates. This is similar to the unix 'which' command.
• WMOM Find mean and sigma of an array, weighting by the standard deviation of each point
• XY2RD Compute R.A. and Dec in degrees from X and Y and an astrometry structure (extracted by EXTAST) from a FITS header. A tangent (gnomonic) projection is computed directly; other projections are computed using
• ZERO_STRUCT "Zero" all the elements in a structure. Numbers are set to zero, strings to '' etc.