| A | acisreadcorr | tools::acis | Flag and relocate out-of-time CCD events | 
| acis_bkgrnd_lookup | tools::background | Find the matching ACIS "blank-sky" dataset for an observation | 
| acis_build_badpix | tools::acis | Create an observation-specific bad-pixel file | 
| acis_check_pha_range | tools::acis | Compute approximate energy range for on-orbit PHA filter. | 
| acis_clear_status_bits | tools::acis | Clear (set to 0) ACIS status bits before reprocessing with acis_process_events | 
| acis_detect_afterglow | tools::acis | Identify and flag cosmic ray afterglows | 
| acis_fef_lookup | tools::response | Find the FITS Embedded Function file for use by mkrmf | 
| acis_find_afterglow | tools::acis | Identify cosmic-ray afterglows and hot pixels for TIMED mode observations | 
| acis_process_events | tools::acis | Produce or update the time, coordinate, pulse-height, grade, and status information in ACIS event files | 
| acis_set_ardlib | tools::response | Sets the bad pixel parameters of the ardlib file to the given file | 
| acis_streak_map | tools::acis | Generate high frequency background maps (streakmaps) which identify ACIS streaks caused when bright source photons are applied to the wrong pixel during readout. | 
| aconvolve | tools::image | Convolve an N-dimensional image with a kernel | 
| acrosscorr | tools::image | Cross-correlate two N-dimensional images or autocorrelate an image | 
| addresp | tools::response | Add multiple RMFs, weighted by ARFs and exposures; add mutiple ARFs, weighted by exposures. | 
| add_colvals | contrib | Add a column to a crate given a name and array of values | 
| add_col | crates | Add a column to a crate. | 
| add_crate | crates | Add a crate to a dataset. | 
| add_key | crates | Add a keyword to a crate given a CrateKey object. | 
| add_piximg | crates | Add an image to a crate. | 
| ahelp | ahelp | Access the CIAO help documentation. | 
| aplimits | tools::statistics | Compute upper limits for the detection of a source, using data obtained from background apertures in event lists, images, and exposure maps. | 
| apowerspectrum | tools::image | Compute the power spectrum of an N-dimensional input array, or from two columns (independent/dependent variable) in an input file | 
| apply_fov_limits | tools::utilities | Create an image that matches the FOV file for the observation | 
| apply_transform | transform | Apply a transform to the given data. | 
| aprates | tools::statistics | Compute net counts, rate, and/or flux, plus credible intervals, for a point source, using data obtained from source and background apertures in event lists, images, and exposure maps. | 
| ardlib | calibration | Analysis Reference Data Library | 
| arestore | tools::image | Restore image resolution using deconvolution techniques | 
| arfcorr | tools::response | Calculate a point source aperture correction, either as a single-energy image or as an energy-dependent correction to the ARF file. | 
| asphist | tools::aspect | Bin the aspect solution into a 3D histogram of duration vs pointing offset and roll offset. | 
| asp_offaxis_corr | tools::aspect | Applies off-axis boresight correction to an L1 Aspect solution file (ASPSOL). | 
| autoname | concept | Autonaming is a feature available in various tools for automatically naming an output file based upon the name of an input file. | 
| axbary | tools::timing | Apply barycentric corrections to event times, GTIs, and header values. | 
| 
 | 
| B | bkg_fixed_counts | tools::region | Create a background region with a fixed number of counts | 
| blanksky_image | tools::background | Create scaled background and background-subtracted images given an observation-specific blanksky background file and a reference image. | 
| blanksky_sample | tools::background | Create a scaled background events file by using the scale factor calculated by and sampling the blanksky background file generated by the "blanksky" script for an observation. | 
| blanksky | tools::background | Tailor an unscaled blanksky background file to be compatible with a given events file; combining and reprojecting the necessary background files from the CalDB. | 
| 
 | 
| C | caldb | calibration | CALibration DataBase (CALDB) | 
| calindex | tools::caldb | Create an index file or append data on an existing one of calibration database (CALDB) products. | 
| calmerge | tools::caldb | Merge index files of calibration database (CALDB) products. | 
| calquiz | tools::caldb | Find calibration files in the CALDB | 
| calvalid | tools::caldb | Validate index file of calibration database (CALDB) products. | 
| cda_data | contrib | Download public data by ObsId from the Chandra archive (Python interface). | 
| cda_search | contrib | Find publicly-available Chandra ObsIds from the Chandra archive (Python interface). | 
| celldetect | tools::detect | Use a "sliding cell" to search for sources | 
| centroid_map | tools::image | Adaptively bin an image using centroid map algorithm | 
| chandra_repro | tools::composite | Reprocess a Chandra dataset | 
| check_caldb_version | contrib | Check whether the locally-installed version of the Chandra Calibration DataBase (CALDB) is up to date | 
| check_ciao_caldb | tools::utilities | A tool to test the installation of the CIAO Calibration Database (CALDB) | 
| check_ciao_version | tools::utilities | Check that the CIAO and CALDB installations are up to date. | 
| ciao-install | concept | Download and install CIAO, CALDB, MARX, and the contributed script files | 
| ciaorc | concept | (OBSOLETE) The .ciaorc file provides user-configuration options for CIAO | 
| ciao_caldb | contrib | Utility routines for the CIAO CALDB (CIAO contributed package). | 
| ciao_contrib | contrib | Useful Python routines for CIAO. | 
| ciao_proptools | contrib | Experimental interface to the Chandra proposal tools (CIAO contributed package). | 
| ciao_runtool | contrib | Run CIAO tools from Python as if they were functions (CIAO contributed package). | 
| ciao_smooth | contrib | Simple smoothing routines for 2D data | 
| ciao_stacklib | contrib | Support routines for using stacks in CIAO (CIAO contributed package). | 
| ciao_utils | contrib | Utility routines for CIAO (CIAO contributed package). | 
| ciao | concept | Chandra Interactive Analysis of Observations | 
| colden | proposaltools | COLDEN is an interactive program to evaluate the neutral hydrogen column density at a given direction on the sky | 
| collect_chandra_dois | tools::collect_chandra_dois | A tool that scans a directory for Chandra data products and produces a list of data identifiers. | 
| color_color | tools::response | Creates a Color-Color diagram | 
| col_exists | crates | Determine if a column exists in a crate. | 
| combine_grating_spectra | tools::composite | Combine Chandra gratings PHA files and their associated response files. | 
| combine_spectra | tools::composite | Combine PHA files and their associated response files. | 
| convert_ds9_region_to_ciao_stack | tools::region | Convert ds9 region file containing special shapes to CIAO stack. | 
| convert_xspec_script | tools::utilities | Convert a XSPEC save file to Sherpa commands *experimental* | 
| convert_xspec_user_model | tools::utilities | Compile a XSPEC user model for use in Sherpa *experimental* | 
| coords_chandra | contrib | Utility routines for working with Chandra Coordinates | 
| coords_format | contrib | Convert between string and numeric formats for Astronomical positions. | 
| coords_gratings | contrib | Object to convert to/from Chandra grating coordinates. | 
| coords_utils | contrib | Utility routines for working with Astronomical positions. | 
| coords | chandra | Coordinate systems used in Chandra analysis | 
| copy_colvals | crates | Copy the column values from a crate. | 
| copy_piximgvals | crates | Copy the image values from a crate. | 
| copy_transform | transform | Copy the transform. | 
| correct_periscope_drift | tools::aspect | Correct a Chandra aspect solution for temporal drift calculated from a fit of the drift in the sky positions of the events in a supplied circle region. | 
| cratedataset | crates | The CrateDataset object is used to read and write files with multiple blocks. | 
| cratedata | crates | The CrateData object is used to store column or image data. | 
| cratekey | crates | The CrateKey object is used to represent a header item (keyword and value) for a file. | 
| crates_contrib | contrib | Contributed CIAO routines for Crates. | 
| crates_images | contrib | Image-related routines for Crates (CIAO contributed package). | 
| crates_utils | contrib | Utility routines for Crates (CIAO contributed package). | 
| crates | crates | Reading, writing, and changing ASCII and FITS files in Python | 
| crate | crates | The TABLECrate and IMAGECrate objects represent a block in a file. | 
| create_bkg_map | tools::background | Create a background map for ACIS and HRC from the event files. | 
| create_vector_column | crates | Create a vector column. | 
| create_virtual_column | crates | Create a virtual column. | 
| csmooth | tools::image | Adaptively smooth a 2-D image | 
| 
 | 
| D | dates | proposaltools | DATES is an interactive calendar and time conversion tool. | 
| dax | tools::composite | Run CIAO tasks from the ds9 Analysis menu | 
| deflare | tools::timing | deflare - remove flares from light curves using lc_clean or lc_sigma_clip | 
| delete_col | crates | Delete a column from a crate. | 
| delete_key | crates | Delete a keyword from a crate. | 
| delete_piximg | crates | Delete an image from a crate. | 
| destreak | tools::acis | Remove streak events from ACIS data | 
| detilt | tools::gratings | Correct the time-dependent tilt of LETG/HRC-S spectra by adjusting TG_D. | 
| dewiggle | tools::gratings | Straighten LETG/HRC-S spectra by applying tg_d adjustments. | 
| dither_region | tools::aspect | Compute fraction of region area that covers chips | 
| dmappend | tools::core | Append multiple blocks/extensions to an existing output file. | 
| dmarfadd | tools::response | Add multiple grating ARF files together, weighting by exposure. | 
| dmascii | dm | Using the Data Model with text files | 
| dmbinning | dm | The CIAO binning syntax | 
| dmcontour | tools::region | Make contour regions from a 2-D image | 
| dmcoords | tools::coordinates | Convert between Chandra coordinate systems | 
| dmcopy | tools::core | Filter and bin tables and images. | 
| dmdiff | tools::core | Compare values in two files. | 
| dmellipse | tools::region | Finds ellipse for specified fraction | 
| dmextract | tools::core | Make a histogram table file (e.g. PHA file, lightcurve file) from a table column. Generate count histogram on supplied regions for a spatial table or image file. | 
| dmfiltering | dm | Filtering tables and images with the Data Model | 
| dmfilth | tools::image | Replace pixel values in source regions of an image with values interpolated from surrounding background regions | 
| dmgroupreg | tools::region | Translates DS9 regions and groups to CIAO format. | 
| dmgroup | tools::table | Group a specified column in a table with various options | 
| dmgti | tools::timing | Create a Good Time Interval from limits placed on time-based files (event and Mission Time Line files). | 
| dmhedit | tools::header | Edit datamodel file headers | 
| dmhistory | tools::header | Extracts the tool history from the file header | 
| dmimg2jpg | tools::image | Make a color JPEG image (or EPS) from three image files | 
| dmimgadapt | tools::image | Adaptively smoothes an image based on number of counts | 
| dmimgblob | tools::image | Identifies groups of pixels above/below threshold | 
| dmimgcalc | tools::image | Perform arithmetic on images | 
| dmimgdist | tools::image | Computes the distance transform of image | 
| dmimgfilt | tools::image | Performs various non-linear image filtering techniques. | 
| dmimghist | tools::image | Create a histogram of the pixel values in a 2-D image | 
| dmimghull | tools::region | Create convex polygon around pixels in an image | 
| dmimglasso | tools::region | Draw region around point with similar values | 
| dmimgpick | tools::image | Maps image values to rows in a table | 
| dmimgpm | tools::image | Compute a low frequency spatial (modified poisson mean) background map | 
| dmimgproject | tools::image | Project image along axis | 
| dmimgreproject | tools::image | Replicates table value along axis of image | 
| dmimgthresh | tools::image | Set low (or high) intensity or exposure regions of an image to a constant value. | 
| dmjoin | tools::table | Join two files whose sampling is different. | 
| dmkeypar | tools::header | Retrieve information about a keyword from an input file | 
| dmlist | tools::core | List contents or structure of a file. | 
| dmmakepar | tools::header | Write header keywords to a parameter file | 
| dmmakereg | tools::region | Convert the format of a region file (swap between ASCII and CXC FITS) | 
| dmmaskbin | tools::image | Bins an image based on input mask | 
| dmmaskfill | tools::image | Replaces mask values with those found in lookup table | 
| dmmasks | dm | CIAO mask filtering syntax | 
| dmmath | concept | Syntax used for writing mathematical operations in dmtcalc, dmimgcalc, and dmgti | 
| dmmerge | tools::table | Merge two or more compatible tables (e.g. event files) into one. | 
| dmnautilus | tools::image | Perform a quad-tree adaptive binning on 2D images | 
| dmopt | dm | Controlling Data Model internal options | 
| dmpaste | tools::table | Add new columns to a table. | 
| dmradar | tools::image | Perform polar quad-tree adaptive binning on 2D images | 
| dmreadpar | tools::header | Create header keywords from a parameter file | 
| dmregions | dm | CIAO region filtering syntax | 
| dmregrid2 | tools::image | shift, rotate, scale images | 
| dmregrid | tools::image | Rebin a stack of 2-dimensional images. | 
| dmsort | tools::table | Sort a table. | 
| dmstat | tools::statistics | Compute statistics for images and columns in tables. | 
| dmtabfilt | tools::table | Apply non-linear filters to columns in table | 
| dmtcalc | tools::table | Modify and create columns in a table | 
| dmtype2split | tools::table | Split up an array column into multiple files (e.g. PHA type 2 to PHA type 1). | 
| dm | dm | CIAO Data Model: syntax for filtering and binning files | 
| download_chandra_obsid | tools::download | Download public data by ObsId from the Chandra archive. | 
| download_obsid_caldb | tools::download | Download the CALDB files required to analyze an OBS_ID | 
| 
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| E | ecf_calc | tools::response | Obtain the encircled counts fraction of an object as a function of radius. | 
| eff2evt | tools::response | Compute the flux and look up the QE & effective area for event positions | 
| energy_hue_map | tools::image | Creates a true color image using median-energy map and counts image. | 
| evalpos | tools::image | Get image values at a specified (RA,DEC) | 
| eventdef | chandra | Column definition in Chandra event files | 
| 
 | 
| F | find_chandra_obsid | tools::download | Find, and optionally download, publicly-available Chandra ObsIds from the Chandra archive. | 
| find_mono_energy | tools::response | Compute monochromatic for energy band given input spectrum and responses. | 
| fine_astro | tools::coordinates | Automate the steps to apply a fine astrometric correction | 
| fluximage | tools::composite | Create exposure-corrected images and exposure maps for an observation. | 
| flux_obs | tools::composite | Combine reprojected observations to create an exposure-corrected image. | 
| FOVFiles | contrib | Check which FOV files contains the specified RA,Dec location. | 
| fullgarf | tools::response | Create a grating ARF for a particular order and grating for a given observation. | 
| 
 | 
| G | get_axis_transform | crates | Return the axis transform from an IMAGECrate. | 
| get_caldb | contrib | Access various information about the Chandra Calibration DataBase (CALDB) | 
| get_colvals | crates | Get the column values from a crate. | 
| get_col_names | crates | Return an array of the column names in a crate. | 
| get_col | crates | Return a CrateData object of a column from a crate. | 
| get_crate_item_type | crates | Return the type of the crate item as a string. | 
| get_crate_type | crates | Return the type of the crate as a string. | 
| get_crate | crates | Get a crate from a dataset. | 
| get_dither_parameters | tools::aspect | Determine the approximate dither period and amplitude used during an observation. | 
| get_fov_limits | tools::utilities | Find the region (bounding box) covered by a FOV file in sky coordinates | 
| get_keyval | crates | Return the value of a keyword in a crate. | 
| get_key_names | crates | Return an array of the keywords in a crate. | 
| get_key | crates | Return a CrateKey object of a keyword from a crate. | 
| get_number_cols | crates | Return the number of columns in a crate. | 
| get_number_rows | crates | Return the number of rows in a crate. | 
| get_piximgvals | crates | Get the pixel values from an image crate. | 
| get_piximg_shape | crates | Get the dimensions of the image stored in the IMAGECrate. | 
| get_piximg | crates | Return a CrateData object of an image from a crate. | 
| get_sky_limits | tools::utilities | Find the region covered by an image in sky coordinates | 
| get_src_region | tools::detect | Outputs regions that have counts higher than background | 
| get_transform_matrix | crates | Extract the transform matrix from a crate. | 
| get_transform_type | transform | Return the flavor of the input Transform object. | 
| get_transform | crates | Extract the coordinate transform from a crate. | 
| glvary | tools::timing | Search for variability using Gregory-Loredo algorithm. | 
| group | group | Provides the Python interface to the CXC grouping library | 
| grpAdaptiveSnr | group | Adaptively group an array by signal to noise. | 
| grpAdaptive | group | Group an array by the number of counts per group using an adaptive scheme. | 
| grpBinFile | group | Group an array using the grouping applied to another dataset. | 
| grpBinWidth | group | Group an array into a set of equal-width groups (by group width). | 
| grpBin | group | Group an array using low and high boundaries. | 
| grpGetChansPerGroup | group | Calculate the number of channels (elements) in each group. | 
| grpGetGroupSum | group | Apply the supplied grouping to an array. | 
| grpGetGrpNum | group | Calculate the group number for each element in the array. | 
| grpMaxSlope | group | Group an array so that its absolute gradient is above a user-defined limit. | 
| grpMinSlope | group | Group an array so that its absolute gradient is below a user-defined limit. | 
| grpNumBins | group | Group an array into a set of equal-width groups (by number of groups). | 
| grpNumCounts | group | Group an array by the number of counts per group. | 
| grpSnr | group | Group an array by signal to noise. | 
| gti_align | tools::timing | Align GTI to ACIS exposure times | 
| 
 | 
| H | hexgrid | tools::image | Create a regular hexagonal grid and apply to input image | 
| history | concept | A record of the tools that were run, along with the parameter settings, on a file. | 
| hrc_bkgrnd_lookup | tools::background | Find the matching HRC "blank-sky" dataset (event file or spectrum) for an observation | 
| hrc_build_badpix | tools::hrc | Create observation-specific bad pixel file for HRC | 
| hrc_dtfstats | tools::hrc | Calculate statistics from hrc_calc_dead_time and a GTI | 
| hrc_process_events | tools::hrc | Correct HRC event positions, times, PHA, etc. | 
| 
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| I | identify_name | contrib | Find the position of an astronomical object using NED or CDS. | 
| imextent | contrib | Create a linear 2D transformation for the axes of an image | 
| imgmoment | tools::statistics | Computes image moments (sum, mean, size, angle, etc). | 
| install_marx | tools::download | Automatically download and install MARX | 
| is_pha | crates | Determine if the crate dataset contains a PHA file and its type. | 
| is_rmf | crates | Determine if the crate dataset contains an RMF. | 
| is_virtual | crates | Determine if the input column from the crate is a virtual column. | 
| 
 | 
| K | key_exists | crates | Determine if the keyword exists in the crate. | 
| 
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| L | lc_clean | contrib | lc_clean - remove periods of high (or low) count rates using the same technique as the ACIS background files | 
| lc_sigma_clip | contrib | lc_sigma_clip - remove flares from a light curve using an iterative sigma-clipping algorithm | 
| level | chandra | Describes the amount of processing performed to create a given product. | 
| lightcurves | contrib | lightcurves - routines to remove periods of anomalously high (or low) count rates in a lightcurve | 
| lim_sens | tools::statistics | Create an output limiting sensitivity map with the same blocking factor, dimensions and WCS | 
| 
 | 
| M | make_image_crate | contrib | Create an IMAGECrate from an array. | 
| make_instmap_weights | tools::response | make_instmap_weights - produces a weighted spectrum file usable with mkinstmap in order to create a weighted exposure map. | 
| make_psf_asymmetry_region | tools::response | Create a region that shows the location of the HRMA PSF asymmetry for a source | 
| make_table_crate | contrib | Create a TABLECrate from a set of arrays, a dictionary, or a structured array. | 
| map2reg | tools::image | Convert a map file into a region file. | 
| mean_energy_map | tools::response | Creates an image whose pixels are the mean energy of the events | 
| merge_obs | tools::composite | Reproject and combine multiple observations to create a merged event file and exposure-corrected images. | 
| merge_too_small | tools::image | Adjust input map file to meet some minimum criteria | 
| merging_rules | concept | A description of the merging rules used when combining header information. | 
| mkacisrmf | tools::response | Generate an RMF for Chandra imaging data | 
| mkarf | tools::response | Generate an ARF for Chandra imaging data (and grating 0th order) | 
| mkexpmap | tools::response | Generate a Chandra imaging exposure map (effective area vs. sky position) | 
| mkgarf | tools::response | Generate a Chandra Grating ARF for one detector element. | 
| mkgrmf | tools::response | Generate an RMF for Chandra grating data | 
| mkinstmap | tools::response | Generate a Chandra instrument map (effective area vs. detector position) | 
| mkosip | tools::response | Generate an OSIP calibration file. | 
| mkpsfmap | tools::response | Look up the radius of the PSF for each pixel in an image | 
| mkregmap | tools::image | Create map from stack of input regions. | 
| mkrmf | tools::response | Generate an RMF for Chandra imaging data | 
| mkrprm | tools::response | Compute the aperture correction for radial profiles | 
| mktgresp | tools::response | Create ARF and RMF files for each spectral order and grating arm in a TypeII PHA file | 
| mkwarf | tools::response | Generate a weighted ARF. | 
| modelflux | tools::response | Calculate model flux or count rate | 
| monitor_photom | tools::aspect | Generate a photometric lightcurve from ACA monitor data. | 
| mtl_build_gti | tools::timing | Create Good Time Interval from Mission Time Line and limits | 
| mtl | chandra | A description of the Mission Time Line (MTL) | 
| multi_chip_gti | tools::acis | Create a combined GTI file for multiple ACIS chips | 
| 
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| O | obsid_search_csc | tools::download | Search the Chandra Source Catalog by OBS_ID | 
| obsvis | proposaltools | ObsVis is the Observation Visualizer created at the Chandra Science Center in Cambridge Massachusetts, USA. | 
| 
 | 
| P | paccess | paramio | Returns the path to the specified parameter file. | 
| paccess | tools::parameter | Gives the location of a tool's parameter file | 
| paramclose | paramio | Close a parameter file opened by paramopen. | 
| parameter | concept | Describes the parameter interface used by CIAO. | 
| paramio | paramio | The Python interface to the CXC parameter system | 
| paramopen | paramio | Open a parameter file. | 
| patch_hrc_ssc | tools::hrc | Identify and patch HRC Secondary Science Corruption (SSC) data | 
| pathfinder | tools::image | Group pixels by steepest gradient ascent to local maximum | 
| pdump | tools::parameter | Dumps the values of the parameters, with one parameter per line. | 
| pfold | tools::timing | Folds events into multiple periods | 
| pgets | paramio | Read/write individual parameter values. | 
| pget | paramio | Get a parameter value as a string. | 
| pget | tools::parameter | Get parameter values | 
| pileup_map | tools::response | Compute image that gives indication of pileup. | 
| pileup | chandra | An overview of pileup in the Chandra ACIS detector. | 
| pimms | proposaltools | PIMMS (Portable, Interactive Multi-Mission Simulator) converts source fluxes and count rates between missions. | 
| pline | tools::parameter | Display the parameter values, with all parameters on a single line | 
| plist | paramio | Get list of parameter names. | 
| plist | tools::parameter | List the contents of a parameter file. | 
| pquery | paramio | Query a parameter value. | 
| pquery | tools::parameter | Query whether a parameter exists and, if so, get and return its value. | 
| precess | proposaltools | PRECESS is an interactive astronomical coordinate conversion program. It provides precession of equatorial coordinates and conversion between equatorial, ecliptic, galactic, and supergalactic coordinates. | 
| print_crate_names | crates | Display information on data from a crate. | 
| prop-coords | proposaltools | Defines available coordinate systems for Chandra Proposal Tools | 
| prop-time | proposaltools | Defines available calendars and timescales for command line versions of Chandra Proposal Tools | 
| prop-tools | proposaltools | Tools that aid in the preparation and submission of Chandra proposals | 
| pset | paramio | Set a parameter value. | 
| pset | tools::parameter | Set parameter values on the command line | 
| psfsize_srcs | tools::region | Compute the size of a circle enclosing a specified fraction of PSF. | 
| psf_contour | tools::region | Create a source region file from a simulated PSF | 
| psf_project_ray | tools::response | Project rays generated by ChaRT onto a semi-infinite detector plane. | 
| psf | psf | A Python module to calculate the size or enclosed-counts fraction of the Chandra PSF | 
| punlearn | paramio | Restore the system defaults for a parameter file. | 
| punlearn | tools::parameter | Restore system default parameter values | 
| python | scripting | Python is a dynamic object-oriented programming language used by CIAO | 
| 
 | 
| R | r4_header_update | tools::utilities | Update file header with various keywords to match latest archive processing | 
| rank_roi | tools::region | Assign overlapping region area to highest ranking source. | 
| readout_bkg | tools::background | Approximate the Out Of Time source contribution to the background. | 
| read_dataset | crates | Read all contents of a file. | 
| read_ds9_contours | contrib | Read in the contours from a ds9 *.con file with optional coordinate conversion. | 
| read_file | crates | Read FITS or ASCII data into a crate. | 
| read_pha | crates | Load a PHA file into a PHACrateDataset. | 
| read_rmf | crates | Load an RMF file into a RMFCrateDataset. | 
| regArea | region | *DEPRECATED* Calculate the area enclosed by a region. | 
| regExtent | region | *DEPRECTATED* Calculate the bounding box of a region. | 
| regInsideRegion | region | *DEPRECATED* Is a point (or set of points) inside a region? | 
| region-old | region | *DEPRECATED* Provides the Python interface to the CXC region library | 
| region | region | Provides a Python interface to the CXC region library | 
| regParse | region | *DEPRECATED* Parse a region for use by the routines in the region library | 
| regphystocel | tools::region | Convert regions in physical coordinates to ds9 format regions in celestial (fk5) coordinates. | 
| regPrintRegion | region | *DEPRECATED* Print out diagnostic details about a region. | 
| regRegionString | region | *DEPRECATED* Converts a region object into a string. | 
| reproject_aspect | tools::coordinates | Modify aspect solution file RA, Dec, and roll or updfile WCS to minimize position differences between two source lists. | 
| reproject_events | tools::coordinates | Regrid an event file to a different tangent point | 
| reproject_image_grid | tools::coordinates | Projects image(s) from one WCS to another | 
| reproject_image | tools::coordinates | Projects image from one WCS to another | 
| reproject_obs | tools::composite | Reproject a set of observations to a common tangent point and create a merged event file. | 
| rmfimg | tools::response | Create a simple image of an RMF or ARF file | 
| roi | tools::region | Generates source and background regions from source list | 
| 
 | 
| S | scale_image_crate | contrib | Scale the pixel values in an IMAGE crate. | 
| search_csc | tools::download | Perform a position search on the Chandra Source Catalog | 
| set_colvals | crates | Set the values of a column in a crate. | 
| set_keyval | crates | Set the keyword value in a crate. | 
| set_key | crates | Add a keyword to a crate given a name and a value. | 
| set_piximgvals | crates | Set the pixel values in an image crate. | 
| simplecoordtransform | contrib | Convert between the different coordinate systems of an image. | 
| simple_hist | contrib | Create a one-dimensional histogram of a data array | 
| simple_stats | contrib | Calculate several basic statistic values for a data array | 
| simulate_psf | tools::response | Simulate the Chandra PSF | 
| sky2tdet | tools::coordinates | Project an image in SKY coordinates to TDET coordinates | 
| skyfov | tools::region | Make a field-of-view region in sky coordinates | 
| smooth_image_crate | contrib | Smooth the pixel values in an IMAGE crate. | 
| specextract | tools::composite | Create source and optional background spectra for Chandra imaging-mode and zeroth-order grating data. | 
| splitobs | tools::utilities | `splitobs' separates the data products for Multi-Obi and ACIS interleaved observations | 
| splitroi | tools::region | Convert the output of roi into a format usable by dmfilth | 
| srcextent | tools::composite | Determine if a source is extended within a confidence interval. | 
| srcflux | tools::composite | Calculate the net count rates and fluxes, including uncertainties, of sources in a Chandra observation. | 
| src_psffrac | tools::response | Compute approximate PSF fraction in circular source region | 
| sso_freeze | tools::coordinates | Reproject sky x and y coordinates into a Solar System Object centered reference frame. | 
| stack | concept | How to set a parameter to more than one value using a stack. | 
| statmap | tools::statistics | Compute simple statistics for events in each map region. | 
| stk_build | tools::stacks | stk_build is used to build a stack from a user-defined string. The output is to stdout, stderr, or a file. | 
| stk_count | tools::stacks | stk_count is used to count the number of items in a stack. The output is to the stk_count parameter file. | 
| stk_read_num | tools::stacks | stk_read_num is used to read one element of a user-defined stack. The output is to the outelement field of the stk_read_num parameter file. | 
| stk_where | tools::stacks | stk_where finds the location of an item in a stack | 
| subspace | concept | Describes the filtering applied to a file | 
| summarize_status_bits | tools::utilities | Summarize the status bits in a Chandra event file. | 
| symmetrize | tools::gratings | Adjust the tg_d values of LETG/HRC-S evt2 data to make cross-dispersion profiles more symmetric | 
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| T | tgdetect2 | tools::gratings | Bundles three programs: tg_findzo, tg_choose_method, and tgdetect into one in order to provide a more convenient interface for determination of the zeroth order centroid. | 
| tgdetect | tools::gratings | Detect and centroid the zero order image in a spatial sub-region of a grating event list. | 
| tgextract2 | tools::gratings | Bin event list grating wavelengths column into a one-dimensional counts histogram, by source, grating part, and diffraction order. Optionally bin background spectrum. | 
| tgextract | tools::gratings | Bin event list grating wavelengths column into a one-dimensional counts histogram, by source, grating part, and diffraction order. | 
| tgidselectsrc | tools::gratings | Filter an input source list based upon a SNR threshold. | 
| tgmask2reg | tools::gratings | Customize grating extaction region file for use with tgextract2 | 
| tgmatchsrc | tools::gratings | Match sources between two source lists by their 2-D separation files. | 
| tgsplit | tools::gratings | Split a TYPE:II grating PHA file into several TYPE:I files | 
| tg_bkg | tools::gratings | Creates a PHA background file for use in XSPEC | 
| tg_choose_method | tools::gratings | Automatically choose between tgdetect and tg_findzo for determining the zeroth order centroid | 
| tg_create_mask | tools::gratings | Create a region file to define spectrum sky boundaries | 
| tg_findzo | tools::gratings | Find the zeroth order sky X,Y centroid for bright sources observed using HETG or LETG gratings with the ACIS-S detector. | 
| tg_resolve_events | tools::gratings | Assign grating events to spectral orders; use detector energy resolution for order separation, if available. | 
| times | chandra | "Times" used in Chandra datasets and Chandra data analysis | 
| transform | transform | TRANSFORMS - Coordinate transforms in Python | 
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| V | vtbin | tools::image | Create adaptive bin image using Voronoi Tessellation | 
| vtpdetect | tools::detect | Voronoi Tessellation and Percolation (VTP) source detection | 
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| W | wavdetect | tools::detect | Mexican-Hat Wavelet source detection (wtransform+wrecon) | 
| wcs_match | tools::coordinates | Create a frame transformation to minimize the aspect difference between data from the same sky region. | 
| wcs_update | tools::coordinates | Modify aspect solution file RA and Dec or infile WCS based on a transformation matrix. | 
| wrecon | tools::detect | Combine wavelet transform coefficients into sources | 
| write_arrays | contrib | Write arrays to an ASCII file | 
| write_columns | contrib | Write out arrays (columns) to a file as a table (ASCII or FITS format). | 
| write_dataset | crates | Write a dataset to an output file. | 
| write_file | crates | Write a crate to an output file. | 
| write_pha | crates | Write a PHACrateDataset to a file. | 
| write_rmf | crates | Write an RMFCrateDataset to a file. | 
| wtransform | tools::detect | Obtain wavelet transform coefficients for poisson image data |