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diff --git a/noao/digiphot/daophot/doc/specs/daophot.spc b/noao/digiphot/daophot/doc/specs/daophot.spc new file mode 100644 index 00000000..221630d5 --- /dev/null +++ b/noao/digiphot/daophot/doc/specs/daophot.spc @@ -0,0 +1,1047 @@ +.help daophot Sep87 "Crowded Field Stellar Photometry' +.sh +1. Introduction + + The DAOPHOT package will provide a set of routines for performing +stellar photometry on crowded fields in either interactive or batch mode. +DAOPHOT works by fitting an empirical point spread function (PSF) +to each object in the field +allowing for overlap of closely spaced images. This document presents the +the requirements and specifications for the package and describes some of +the algorithms to be used. Most of the algorithms are described in +the original article by Peter Stetson (1987 P.A.S.P. 99,191). + +.sh +2. Requirements +.ls 4 +.ls (1) +The tasks in the DAOPHOT package shall take as input an IRAF imagefile +containing two-dimensional image data which has been corrected for +pixel to pixel gain variations, high frequency variations in the background, +any nonlinearitys in the data except for those which can be specified as +a lower and/or upper bound, +and any other instrumental defects affecting the intensity value of an +individual pixel. However, it shall be possible to exclude bad pixels, +rows or columns from analysis by DAOPHOT routines in a very crude manner. +.le +.ls (2) +The tasks in the package which produce tabular output shall use the +SDAS Tables for their output and those tasks which read output from other +DAOPHOT tasks will be able to read SDAS Tables. In the future the input/output +shall make use of the DBIO package. +.le +.ls (3) +The DAOPHOT package shall work in conjunction with the APPHOT package produced +at NOAO. DAOPHOT will not have any provision to do aperture photometry of its +own. The output format from DAOPHOT tasks will be consistent with APPHOT. +.le +.ls (4) +Given as input a reduced two-dimensional image which has been processed by the +APPHOT package, the DAOPHOT package shall be able to perform the following +functions: +.ls 4 +.ls o +Interactively define a PSF for the data frame. The PSF will be defined +empirically from one or more stars in the field. The task to determine the +PSF shall be interactive and the user shall be able to use a +graphics terminal and/or an image display device to select the stars which +will make up the PSF. The user will be able to evaluate the PSF through +different means including contour plots, 3-d mesh plots, and displaying the +PSF on an image display device. +The user shall be able to "mask" out parts of the PSF which may be contaminated +by nearby stars, bad pixels etc. Only the non-masked portions of the PSF will +be used in the fitting routines. +.le +.ls o +Fit the PSF simultaneously to groups of stars in the image frame whose +images overlap to some degree. The parameters in the fit shall include the +the object brightness, X and Y position of the star and potentially the sky +background. The sky shall be able to be specified as either a flat uniform +background or a simple tilted planar sky. The photometry routines shall +produce realistic errors in the photometry assuming that realistic numbers +for the characteristics of the data are input. +.le +.ls o +Subtract the fitted stars from the data frame to produce a subtracted +image for further analysis. +.le +.ls o +Add artificial stars to the data frame in order to check accuracy and +completeness in the photometry. The user shall have control over the +number of stars added, the brightness range, the area of the image to contain +the added stars and the noise characteristics of the added stars. +.le +.le +.ls (5) +The DAOPHOT package shall include tasks to inspect and edit the results from the +photometry routines. These shall include tasks such as interactively +rejecting particular stars from the results, +producing plots of errors versus brightness, errors versus position etc. +.le +.ls (6) +The DAOPHOT package shall provide utility packages to handle the output +data from the fitting routines. These shall include such tasks as +aperture growth curves, photometric calibrations, color-magnitude and +color-color diagrams. +.le +.ls (7) +The DAOPHOT routines shall optionally keep a history file to keep +track of the processing done on the images. This will include the values of +various parameters used in the various tasks of the DAOPHOT package. +.le +.ls (8) +The tasks shall be able to be run in batch mode as well as interative +mode. In batch mode use of a graphics terminal or image display shall not +be required. +.le +.ls (9) +The DAOPHOT package shall be written in the SPP language in conformance with +the standards and conventions of IRAF. The code shall be portable and +device independent. +.le +.le +.sh +2.1 Limitations of the Initial DAOPHOT Package + +The DAOPHOT package shall perform PSF fitting photometry with the following +restrictions: +.ls +.ls (1) +The PSF used will be determined empirically and analytic specification of +the PSF will not be possible. This restricts the use of DAOPHOT to image +data which is not too badly undersampled. +.le +.ls (2) +There will be an upper limit to the number of stars for which the PSF will +be fit simultaneously. The initial version of DAOPHOT will have this limit +set to 60 stars. +.le +.ls (3) +The initial version of DAOPHOT will not have the sky included as a parameter +in the fitting routines. +.le +.ls (4) +Initially the use will not be able to mask out bad portions of the PSF for +fitting. +.le +.le + +.sh +3. Specifications + + The DAOPHOT package performs stellar photometry on digital data, maintained +as IRAF image files. DAOPHOT performs this photometry by fitting the PSF +to the stellar images in the image file. DAOPHOT works by fitting the PSF to +a maximum number of stars simultaneously thus allowing for overlapping images. +Input to the package consists of an imagefile and the output from the APPHOT +package, which contains simple aperture photometry for the objects which have +been identified in the image frame, and numerous parameters controlling the +analysis algorithms. Output from the analysis tasks consists of tabular data +containing the results of the analysis routines. The output will be in the +form of SDAS tables and will thus be able to be manipulated by various +other utility tasks available in IRAF. + +The CL callable part of the DAOPHOT package consists of the following routines: + +.ks +.nf + addstar -- adds synthetic stars to an image file + allstar -- fits multiple, overlapping PSFs to star images + *calibrate -- apply photometric calibration + *cmd -- color-magnitude, color-color diagrams + daopars -- DAOPHOT pset parameters + examine -- interactively examine/edit photometry results + group -- divides stars into natural groupings + *growth -- aperture growth curves <--> PSF magnitudes + peak -- fit PSF to single stars in an image file + psf -- interactively construct a PSF for the frame + nstar -- fits multiple, overlapping PSFs to star images + seepsf -- converts a PSF file into a IRAF image file + select -- selects natural groups with a certain range of sizes + substar -- subtract fitted profiles from an image file +.fi +.ke + +There are routines available in other IRAF/STSDAS tasks for manipulating +SDAS Tables or DBIO. The capabilities inside the DAOPHOT are specifically +suited to dealing with large tables of results from these photometry routines. + +.sh +3.1 Standard Analysis Procedures + + Before performing DAOPHOT photometry one must perform certain other tasks +beforehand. This includes using the APPHOT package to produce an object list +and aperture photometry for objects in this list. The DAOPHOT package contains +an additional object finder but one must use APPHOT to obtain the aperture +photometry results. The standard analysis procedure, including APPHOT, is as +follows: +.ls +.ls (1) +Use an object finder to produce a list of object coordinates. This may be done +in many ways: +.ls +.ls o +By using the interactive cusrsor routines available elsewhere in IRAF and +redirecting the output into a list file. +.le +.ls o +By transforming an existing list using an existing IRAF task or the OFFSET +task in the DAOPHOT package. +.le +.ls o +By using an automatic object finding procedure such as the one available +in the APPHOT package or the one in the DAOPHOT package. +.le +.ls o +By any other program which generates a list of objects in suitable format (SDAS +Tables) for input to the APPHOT routines. +.le +.le +.ls (2) +The APPHOT package is run to measure the objects identified in the above +step. One should refer to the APPHOT documentation to understand the +algorithms and procedures which are used in APPHOT. +.le +.ls (3) +One needs to set up the parameters in the analysis routines for this particular +image file. OPTIONS allows you to set such parameters as the number of +electrons/ADC, the fitting radius, and the radius within which the PSF +is defined. +.le +.ls (4) +The next step is to produce a PSF for the image file currently being processed. +In crowed fields this is a tricky, iterative procedure which should be done very +carefully. This is best done using a graphics terminal and/or an image display +device. +.le +.ls (5) +If one plans on using NSTAR, then the GROUP task must be run. This task +divides the stars in the output from the APPHOT into natural groups. The size +of the groups produced depends upon how crowded the field is and what degree of +overlap of the images one considers. +.le +.ls (6) +Use either NSTAR, if you have grouped the objects using GROUP, or +ALLSTAR which will dynamically group the stars as the image file is +processed. These routines will produce the objects' positions and +intrumental magnitudes by means of multiple-profile fits. +.le +.ls (7) +Use SUBSTAR to subtract the fitted profiles from the image file, thus producing +a new image file containing the fitting residuals. This will usually contain +many stars which were missed in the original identification because they lie +in the wings of brighter objects. +.le +.ls (8) +One now basically runs through steps (1) - (6) one or more times, +merging the identified object lists each time to produce a master object list, +until one is satisfied with the final results. There are many subtlties in this +procedure which are described in the DAOPHOT User's Manual. +.le +.ls (9) +After obtaining the photometry results one may edit the results by throwing out +those results which do not meet certain criteria. EXAMINE is an interactive +task which allows the user to examine the results for each individual object +in the list and either accept or reject that object. There are also routines +available for courser rejection of results, e.g. reject all objects with +errors larger than 0.2 magnitudes. +.le +.ls (10) +One may wish to use the tasks to plot up color-color or color-magnitude +diagrams. Other general purpose list processing tools available in +IRAF/SDAS may also be used for analysis of DAOPHOT output. +.le +.le + +.sh +3.2 The ADDSTAR Task + + The function of ADDSTAR is to add synthetic stars to the image file. +These stars may be placed randomly by the computer, placed with a certain +distribution as specifed by the user or at predetermined locations specified +by the user. Likewise the brightness of these added objects may be completely +random or may follow a specified distribution. + +Objects are added by taking the specified PSF, scaling it, and moving it +to the desired location. ADDSTAR will also add Poisson noise to the star +images to make them more realistic. + +.sh +3.2.1 ADDSTAR Parameters + + ADDSTAR has several parameters which control the addition of stars +into a image file. All data dependent parameters are query mode to ensure +that they get set properly for the particular image under consideration. +The data independent parameters are hidden mode, and are given reasonable +default values. The names, datatypes, and default values of the ADDSTAR +parameters are shown below. + +.ks +.nf +Positional or query mode parameters: + + input_image filename + output_image filename + minmag real + maxmag real +.fi +.ke + +.ks +.nf +List structured parameter (filename may be given on command line): + + add_data *imcur +.fi +.ke + +.ks +.nf +Hidden Parameters: + + daopars pset "daophot$daopars.par" + nstar integer 100 + nframe integer 1 + xmin integer 1 + ymin integer 1 + xmax integer NX + ymax integer NY + verbose boolean false +.fi +.ke + +The function and format of each of these parameters is explained in +more detail below. + +.ls +.ls 16 input_image +The name of the image or image section to which artificial stars will be added +.le +.ls output_image +The name of outout image which will contain the added stars. +.le +.ls minmag +The minumum magnitude of artificial star to add to the data. The magnitude +scale is set by the magnitude of the PSF. +.le +.ls maxmag +The maximum magnitude of artificial star to add to the data. The magnitude +scale is set by the magnitude of the PSF. +.le +.ls add_data +This parameter is used to specify a file as input to the ADDSTAR task. This +file should contain centroid positions and magnitudes for the stars you +want to add. It is possible to specify the positions of the added stars +interactively with the image display by setting this parameter to *imcur. +In this case the user is prompted for the magnitude of each star to be added. +If this parameter is the null string then the stars are added in a random +fashion by the ADDSTAR routine. +.le +.ls nstar +The number of artificial stars to add to the input image file. +.le +.ls daopars +This is the name of a file containing parameters which are common to +many DAOPHOT tasks. This pset parameter serves as a pointer to the external +parameter set for the DAOPHOT algorithms. The parameters contained in this +pset and their function are described in section 3.6.1. +.le +.ls nframe +The number of new image files to create. If this parameter is greater +than one then the new image files will use the output image name as +a root and produce image files with '.xxx' appended to the root, where +xxx will range from 001 to nframe. If nframe is one then the output image +name will be used as is. +.le +.ls xmin, ymin, xmax, ymax +These define the subsection of the image in which to add the artificial +stars. The default is to add artificial stars to the complete image. +.le +.ls verbose +Controls the amount of output from the ALLSTAR function. The default is +to have minimal output to STDOUT. +.le +.le + +.sh +3.2.2 ADDSTAR Output + + The output of ADDSTAR consists of two parts, an image file and an +output SDAS Table. The image file is a copy of the input image file but +with the artificial stars generated by ADDSTAR added. The output table +contains the x,y position and magnitude of each of the added stars. When the +nframe parameter is set greater than one then there will be nframe pairs of +output files generated. + +.sh +3.3 ALLSTAR + + ALLSTAR fits multiple, overlapping point-spread functions to stars images +in the input image file. It uses as input the results from APPHOT and an +input PSF and will automatically reduce the entire image performing the necessary +grouping. It will recalculate the grouping after each iteration. ALLSTAR will +also produce the star-subtracted image file. + +.sh +3.3.1 ALLSTAR Parameters + +ALLSTAR has several parameters which control the fitting algorithms. The +names, datatypes, default values for the ALLSTAR parameters are given below. + +.ks +.nf +Positional parameters: + + input_image filename + photometry filename + output filename + sub_image filename +.fi +.ke + +.ks +.nf +Hidden parameters: + + daopars pset "daophot$daopars.par" + max_group integer 60 + redeterm_cent boolean true + max_crit real 2.5 + min_crit real 1.2 + clip_exp integer 6 + clip_range real 2.5 + verbose boolean false +.fi +.ke + +These parameters perform the following functions: + +.ls 4 +.ls 16 input_image +The name of the input image file. +.le +.ls photometry +The name of the input photometry SDAS table. This may contain output from either +the APPHOT package or from NSTAR or previous ALLSTAR runs. +.le +.ls output +The name of the SDAS table to contain the results of the psf fittting. +.le +.ls sub_image +The name of the output image file which will have all of the fitted stars +subtracted from it. If this file is the null string then no star-subtracted +image file will be produced. +.le +.ls daopars +The pset parameter file containing the DAOPHOT parameter set. +.le +.ls max_group +The maximum size group which ALLSTAR will process. The absolute maximum +is 60 stars. +.le +.ls redeterm_cent +If true then the centers of the stars are redetermined before each +iteration. +.le +.ls max_crit +The initial value which ALLSTAR uses as the critical separation for +use in grouping stars together. For groups larger than "max_group" ALLSTAR +will use progressively smaller values for the critical separation until the +group breaks up into units containing fewer than "max_group" stars or until +the value of "min_crit" is reached. +.le +.ls min_crit +The smallest value of the critical separation which ALLSTAR will use in +grouping stars together. +.le +.ls clip_exp, clip_range +These parameters are used to "resist bad data". These two +parameters control the weighting of each pixel as a function of it's +residual from the fit. Clip_range us variable "a" and clip_exp is +variable "b" in the paper by Stetson (P.A.S.P. 99, 191) +.le +.le + +.sh +3.3.2 The ALLSTAR PSF Fitting Algorithm + + The algorithms which ALLSTAR uses to do the psf fitting photometry are +very nearly the same as those used by NSTAR. One is referred to Stetson, +P.A.S.P. 99, 191, for the details on the various fitting, star rejection, +and weighting algorithms used in this task. +.sh +3.3.3 The Output from ALLSTAR + + The output from ALLSTAR consists of three parts. There is the output +photometry results, an SDAS Table, and a subtracted image file. The subtracted +image file is a copy of the input image file minus the fitted stars. + +For each object processed by ALLSTAR there is one row in the output SDAS +Table. Each measured object will have entries for the following items: + +.nf + star, x, y, mag, magerr, sky, niter, chi, sharp + +where + + star star ID number + x,y coordinates of the stellar centroid + mag magnitude relative to the magnitude of the PSF star + magerr estimated standard error of the star's magnitude + sky estimated sky as returned by APPHOT + niter number of iterations for convergence + chi observed pixel to pixel scatter DIVIDED BY the expected + pixel to pixel scatter + sharp an index describing the spatial distribution of the residuals + around the star. Objects with SHARP significantly greater + than zero are extended (possibly galaxies), while objects with + SHARP significantly less than zero may be bad pixels or cosmic + rays +.fi + +Other noteworthy pieces of information will be stored in the output SDAS +Table header. This includes such things as the time and date of processing, +the name of the PSF file, the name of the input photometry file, the +fitting radius etc. + +.sh +3.4 The CALIBRATE Task + +.sh +3.5 The CMD Task + +.sh +3.6 The DAOPARS Task + + This is a pset-task which is used to describe a particular image file +for use with the DAOPHOT package. This pset contains parameters which describe the +data, e.g. the read out noise, the background sky value, the number of photons +per ADC unit, etc., and also parameters which control the DAOPHOT tasks, e.g. +the fitting radius to use. The parameters in this pset are used by several +DAOPHOT tasks, hence their grouping into a pset. + +.sh +3.6.1 daopars Parameters + + The parameters in this task either describe the data in +a particular image file +or are parameters which are used by more algorithms in more than one +DAOPHOT task. The following parameters make up this pset: + +.ks +.nf + + fitrad real 2.5 (pixels) + psfrad real 11.0(pixels) + phot_adc real 10.0 + read_noise real 20.0 + max_good real 32766. + min_good real 0.0 + sky_val real 0.0 + numb_exp integer 1 + comb_type string "average" + var_psf boolean false +.fi +.ke + +The function and format of each of these parameters is described below: + +.ls 4 +.ls 16 fitrad +The fitting radius to use in the PEAK, NSTAR, ALLSTAR and PSF tasks. Only +the pixels within one fitting radius are actually used in the fit. This should +normally be on the order of the FWHM of the stellar images. +.le +.ls psfrad +The radius of the circle within which the PSF is defined. This should be +somewhat larger than the actual radius of the brightest star you are +interested in. +.le +.ls maxgood +The maximum data value in ADC units at which the CCD or other detector +is believed to operate linearly. +.le +.ls mingood +The minimum data value in ADC units which should be used as "real" data. +Dead pixels, bad columns etc. in the image file can be excluded from use in +the analysis by setting this parameters properly. Any data value which +falls below this minimum is ignored by DAOPHOT tasks. +.le +.ls sky_val +The typical sky brightness in ADC units for the image file. This parameter is +updated by the SKY task within the DAOPHOT package. +.le +.ls phot_adc +The number of photons per ADC unit of the CCD or other detector. +.le +.ls read_noise +The readout noise in ADC units of the CCD or other detector. +.le +.ls numb_exp +The number of individual exposures which have been combined to produce the +current image file. This number combined with information on whether the +exposures were summed or averaged is used to get a better handle on the +error estimates of the photometry. +.le +.ls comb_type +Describes whether the individual exposures which went into making up this +image file were "summed" or "averaged" +.le +.ls var_psf +Controls whether the shape of the PSF is to be regarded as constant over the +complete image file. Slight and smooth variations can be accomodated by the +DAOPHOT tasks. +.le +.le + + These parameters should be initially set by the user before starting any +analysis with the DAOPHOT package. Each image file may have it's own set of +parameters and these should be stored in separate pset files. +.sh +3.7 The EXAMINE Task + + EXAMINE allows the user to interactively examine the results of the +DAOPHOT reduction and to accept or reject individual stars. EXAMINE will +accept as input the output photometry list from either ALLSTAR or NSTAR. +For each star in the input list the user can examine either a 3-d meshplot +or a contour diagram of both the input image and the star-subtracted image. +The results of the photometry for the star under consideration is also +displayed. + +Two output star lists are produced using this task. One is a list +of stars which have been "accepted" by the user, the other being a list +of stars which have been "rejected". + +If the TV option is selected then both the original image and subtracted +image are displayed on the "stdimage" and the star under consideration is +identified. The user has the ability to blink these two frames to +evaluate the results of the photometry. + +This task is controlled via input from the terminal with various keys +performing a variety of functions. + +.sh +3.7.1 EXAMINE Parameters + There are several parameters which control various aspects of the +EXAMINE task. The parameters control such things as the input photometry +list, the type of graphical display desired and whether to use the +display capabilities. + +.ks +.nf +Query mode parameters: + + phot_list filename + + fwhm real (pixels) + threshold real (in units of sigma) + output_file filename +.fi +.ke + +.sh +3.9 The GROUP Task + + GROUP is used to divide the stars in the image file into natural +groups prior to analysis with NSTAR. GROUP works on the following +principle: if two stars are close enough that the light of one will +influence the profile fit of the other, then they belong in the same +group. + +.sh +3.9.1 GROUP Parameters + + GROUP only has a few parameters which govern its operation. These +are: + +.ks +.nf +Query mode parameters: + + input_image filename + psf_file filename + crit_overlap real + output filename +.fi +.ke + +.ks +.nf +Hidden mode parameters: + + daopars pset "daophot$daopars.par" +.fi +.ke + +These parameters perform the following functions: + +.ls 4 +.ls 16 input_image +The name of the input image file. +.le +.ls psf_file +The name of the file containing the PSF. +.le +.ls crit_overlap +The "critical overlap" before one star is determined to influence +another. When GROUP examines two stars to see whether they might influence +each others' fits, it firts identifies the fainter of the two stars. It then +calculates the brightness of the brighter star at a distanceof one fitting +radius plus one pixel from the center of the fainter. If this brightness is +greater than the "critical overlap" times the random error per pixel, then +the brighter star is deemed to be capable of affecting the photometry of the +fainter, and the two stars are grouped together. +.le +.ls output +The name of the SDAS table which will contain the stellar groups. +.le +.ls daopars +The name of of a pset file containing the daophot parameters. The specific +parameters which are used from this include the following: +.le +.le +.sh +3.10 The GROWTH Task + +.sh +3.11 The OFFSET task + +.sh +3.12 The PEAK Task + + PEAK fits the PSF to a single star. It is useful for sparsely populated +image files where the stars of interest are not blended. In this cases aperture +photometry is often fine and the use of PEAK is of limited interest. This task +is included in the DAOPHOT package mainly for completeness. + +.sh +3.12.1 PEAK Parameters + + The parameters specific to the PEAK task are used for specifying the +input and output from this routine. The names of the parameters and their +functions are: + +.ks +.nf +Positional or query parameters: + + input_image filename + psf_file filename + output filename +.fi +.ke + +.ks +.nf +Hidden parameters: + + daopars pset "daophot$daopars.par" + verbose boolean false +.fi +.ke + +.ls 4 +.ls 16 input_image +The name of the input image file. +.le +.ls psf_file +The name of the input file containing the point-spread function. +.le +.ls output +The name of the SDAS table to contain the output from PEAK. +.le +.ls verbose +If true then PEAK outputs more information about what it is doing. +.le +.ls daopars +The name of a pset file which contains the parameters specific to the +input image file. The parameters which PEAK uses from this pset include: +sthe fitting radius, the maximum and minimum good data value and whether +a variable PSF is to be used. +.le +.le +.sh +3.13 The PSF Task + + The PSF task is used for obtaining the point-spread function which +will be used in the rest of the DAOPHOT reductions. DAOPHOT uses an +empirical point-spread function as opposed to a mathematically defined +function. The PSF is defined from the actual brightness distribution +of one or more stars in the frame under consideration. It is stored as +a two-component model: (1) an analytic Gaussian profile which approximately +matches the core of the point-spread function, and (2) a look-up table of +residuals, which are used as additive corrections to the integrated +analytic Gaussian function. + +The brightness in a hypothetical pixel at an arbitrary point within the +point-spread function is determined in the following manner. First +the bivariate Gaussian function is integrated over the area of the pixel, +and then a correction is determined by double cubic interpolation +within the lookup table, and is added to the integrated intensity. + +The PSF is stored as a binary data file and is in a format specific +to DAOPHOT. The format of this file is very similar to that used by the +VMS version of DAOPHOT but is stored in binary for compactness. +A function is provided to take the PSF and convert it +to a IRAF image file so that it can be manipulated by other IRAF +tasks. + +PSF allows the user to perform most functions from within the interactive +graphics part of its operation. PSF allows the user to modify the +perspective of hist mesh plot, the contouring interval, the PSF radius +etc. from within the PSF interactive graphics. + +.sh +3.13.1 PSF Parameters + + The PSF task has many parameters which specify the input and +output files as well as specifying other information. These are +divided in query mode parameters and hidden parameters. + +.ks +.nf +Positional or query parameters: + + input_image filename + phot_list filename + psf_stars filename + psf_file filename +.fi +.ke + +.ks +.nf +Hidden parameters: + + daopars pset "daophot$daopars.par" + verbose boolean false +.fi +.ke + +.ls 4 +.ls 16 input_image +The name of the input image file. +.le +.ls phot_list +The name of the input file containing the aperture photometry +results for this image frame. +.le +.ls psf_stars +The name of file coordinate file containing the list of stars +to be used as PSF candidates. +.le +.ls psf_file +The name of the output file for storing the PSF. +.le +.ls verbose +If true then PEAK outputs more information about what it is doing. +.le +.ls daopars +The name of a pset file which contains the parameters specific to the +input image file. The parameters which PEAK uses from this pset include: +sthe fitting radius, the maximum and minimum good data value and whether +a variable PSF is to be used. +.le +.le +.sh +3.14 The NSTAR Task + + NSTAR is one of DAOPHOT's multiple, simultaneous, profile-fitting +photometry routine. It is similar to ALLSTAR except that NSTAR must have +the objects grouped (using the GROUP task) and it does not dynamically +alter the groups while running. NSTAR also does not automatically produce the +star subtracted image file. + +.sh +3.14.1 NSTAR Parameters + + There are several parameters which control the function of the +NSTAR task. These are the following: + +.ks +.nf +Positional or Query Parameters: + + input_image filename + psf_file filename + group_file filename + output_file filename +.fi +.ke + +.ks +.nf +Hidden parameters: + + daopars pset "daophot$daopars.par" + verbose boolean false +.fi +.ke + +.sh +3.15 The SEEPSF Task + + The SEEPSF task produces an IRAF image file from the given PSF +file. This allows other IRAF tasks, especially display and plotting tasks, +to use access the point-spread function. The user has the ability to create +any size of image from the PSF enlargements being handled by a number of +different interpolation schemes. + +.sh +3.15.1 SEEPSF Parameters + + The parameters wich control this task are limted. They basically +control the input, output and size of the image. + +.ks +.nf +Positional or Query Parameters: + + psf_file filename + image_name filename + image_size integer +.fi +.ke + +.ks +.nf +Hidden parameters: + + interpolation string "nearest" + boundary string "constant" + constant real 0.0 + daopars pset "daophot$daopars.par" + verbose boolean false +.fi +.ke + +.ls 4 +.ls 16 psf_file +This specifies the input PSF file which is to be transformed into an +IRAF image. +.le +.ls image_name +The name of the output IRAF image. +.le +.ls image_size +The size of the output image in pixels per side. Note that only square PSFs +and PSF images are alllowed. +.le +.ls interpolation +The type of interpolation to be used in expanding the image. The choices +are "nearest" neighbor, "linear" bilinear, "poly3" bicubic polynomial, +"poly5" biquintic polynomial, and "spline3" bicubic spline. +.le +.ls boundary +The type of boundary extension to use for handling references to pixels +outside the bounds of the input image. The choices are: "constant", +"nearest" edge, "reflect" about the boundary and "wrap" to the other side +of the image. +.le +.le +.sh +3.16 The SELECT Task + + The SELECT task is used to select groups of stars with a particular +range of sizes from a group file which has been produced by GROUP. This +task is used when some of the groups in the group file are large than the +maximum allowed in NSTAR, currently 60 stars. + +.sh +3.16.1 SELECT Parameters + + The parameters which control the SELECT task are the following: + +.ks +.nf +Positional or Query Parameters: + + input_group filename + output_group filename + min_group integer + max_group integer +.fi +.ke + +.le 4 +.ls 16 input_group +The input group file which is to be searched for groups within the +limits specified by min_group and max_group. +.le +.ls output_group +The output group file which will consist of groups between 'min_group' +and 'max_group' in size. +.le +.ls min_group +The minimum group size to be extracted from the input group file. +.le +.ls max_group +The maximum group size to be extracted from the input group file. +.le +.le +.sh +3.17 The SKY Task + +.sh +3.18 The SORT Task + +.sh +3.19 The SUBSTAR Task + + The SUBSTAR command takes the point-spread function for an image +frame and a file containing the x,y coordinates and apparent magnitudes +for a group of stars, usually an output file from one of the photometry +routines, shifts and scales the PSF function +according to each position and magnitude, and then subtracts it from the +original image frame. + +.sh +3.19.1 SUBSTAR Parameters + + The parameters for SUBSTAR control the input and output from this +task. + +.ks +.nf +Positional or Query Parameters: + + psf_file filename + phot_file filename + input_image filename + output_image filename +.fi +.ke + +.ks +.nf +Hidden parameters: + + verbose boolean false +.fi +.ke + +.ls 4 +.ls 16 psf_file +The name of the file containing the PSF which is to be used as the template +in the star subtraction. +.le +.ls phot_file +The file containing the photometry results for the stars which are to be +subtracted from the input image. +.le +.ls input_image +The name of the input image file from which the stars are to be subtracted. +.le +.ls output_image +The name of the output image file which will be a copy of the input frame +except for the subtracted stars. +.le +.ls verbose +If this parameter is set to true then more information about the progress +of SUBSTAR is output. +.le +.le +.sh +4.0 Example + +.endhelp |