From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 8 Jul 2015 20:46:52 -0400 Subject: Initial commit --- noao/imred/specred/doc/doslit.hlp | 1201 +++++++++++++++++++++++++++++++++++++ 1 file changed, 1201 insertions(+) create mode 100644 noao/imred/specred/doc/doslit.hlp (limited to 'noao/imred/specred/doc/doslit.hlp') diff --git a/noao/imred/specred/doc/doslit.hlp b/noao/imred/specred/doc/doslit.hlp new file mode 100644 index 00000000..2bcf7294 --- /dev/null +++ b/noao/imred/specred/doc/doslit.hlp @@ -0,0 +1,1201 @@ +.help doslit Feb93 noao.imred.specred +.ih +NAME +doslit -- Slit spectra data reduction task +.ih +USAGE +doslit objects +.ih +SUMMARY +\fBDoslit\fR extracts, sky subtracts, wavelength calibrates, and flux +calibrates simple two dimensional slit spectra which have been processed to +remove the detector characteristics; i.e. CCD images have been bias, dark +count, and flat field corrected. It is primarily intended for +spectrophotometry or radial velocities of stellar spectra with the spectra +aligned with one of the image axes; i.e. the assumption is that extractions +can be done by summing along image lines or columns. The alignment does +not have to be precise but only close enough that the wavelength difference +across the spectrum profiles is insignificant. The task is available +in the \fBctioslit\fR, \fBkpnoslit\fR, \fBkpnocoude\fR, and \fBspecred\fR +packages. +.ih +PARAMETERS +.ls objects +List of object images to be processed. Previously processed spectra are +ignored unless the \fIredo\fR flag is set or the \fIupdate\fR flag is set +and dependent calibration data has changed. If the images contain the +keyword IMAGETYP then only those with a value of "object" or "OBJECT" +are used and those with a value of "comp" or "COMPARISON" are added +to the list of arcs. Extracted spectra are ignored. +.le +.ls arcs = "" (at least one if dispersion correcting) +List of arc calibration spectra. These spectra are used to define +the dispersion functions. The first spectrum is used to mark lines +and set the dispersion function interactively and dispersion functions +for all other arc spectra are derived from it. If the images contain +the keyword IMAGETYP then only those with a value of "comp" or +"COMPARISON" are used. All others are ignored as are extracted spectra. +.le +.ls arctable = "" (optional) (refspectra) +Table defining which arc spectra are to be assigned to which object +spectra (see \fBrefspectra\fR). If not specified an assignment based +on a header parameter, \fIsparams.sort\fR, such as the Julian date +is made. +.le +.ls standards = "" (at least one if flux calibrating) +List of standard star spectra. The standard stars must have entries in +the calibration database (package parameter \fIcaldir\fR). +.le + +.ls readnoise = "rdnoise", gain = "gain" (apsum) +Read out noise in photons and detector gain in photons per data value. +This parameter defines the minimum noise sigma and the conversion between +photon Poisson statistics and the data number statistics. Image header +keywords (case insensitive) may be specified to obtain the values from the +image header. +.le +.ls datamax = INDEF (apsum.saturation) +The maximum data value which is not a cosmic ray. +When cleaning cosmic rays and/or using variance weighted extraction +very strong cosmic rays (pixel values much larger than the data) can +cause these operations to behave poorly. If a value other than INDEF +is specified then all data pixels in excess of this value will be +excluded and the algorithms will yield improved results. +This applies only to the object spectra and not the standard star or +arc spectra. For more +on this see the discussion of the saturation parameter in the +\fBapextract\fR package. +.le +.ls width = 5. (apedit) +Approximate full width of the spectrum profiles. This parameter is used +to define a width and error radius for the profile centering algorithm. +.le +.ls crval = INDEF, cdelt = INDEF (autoidentify) +These parameters specify an approximate central wavelength and dispersion. +They may be specified as numerical values, INDEF, or image header keyword +names whose values are to be used. +If both these parameters are INDEF then the automatic identification will +not be done. +.le + +.ls dispcor = yes +Dispersion correct spectra? This may involve either defining a nonlinear +dispersion coordinate system in the image header or resampling the +spectra to uniform linear wavelength coordinates as selected by +the parameter \fIsparams.linearize\fR. +.le +.ls extcor = no +Extinction correct the spectra? +.le +.ls fluxcal = no +Flux calibrate the spectra using standard star observations? +.le +.ls resize = no (apresize) +Resize the default aperture for each object based on the spectrum profile? +.le +.ls clean = no (apsum) +Detect and correct for bad pixels during extraction? This is the same +as the clean option in the \fBapextract\fR package. If yes this also +implies variance weighted extraction. In addition the datamax parameters +can be useful. +.le +.ls splot = no +Plot the final spectra with the task \fBsplot\fR? In quicklook mode +this is automatic and in non-quicklook mode it is queried. +.le +.ls redo = no +Redo operations previously done? If no then previously processed spectra +in the object list will not be processed unless required by the +update option. +.le +.ls update = no +Update processing of previously processed spectra if the +dispersion reference image or standard star calibration data are changed? +.le +.ls quicklook = no +Extract and calibrate spectra with minimal interaction? In quicklook mode +only the initial dispersion function solution and standard star setup are +done interactively. Normally the \fIsplot\fR option is set in this mode to +produce an automatic final spectrum plot for each object. It is +recommended that this mode not be used for final reductions. +.le +.ls batch = yes +Process spectra as a background or batch job provided there are no interactive +steps remaining. +.le +.ls listonly = no +List processing steps but don't process? +.le + +.ls sparams = "" (pset) +Name of parameter set containing additional processing parameters. This +parameter is only for indicating the link to the parameter set +\fBsparams\fR and should not be given a value. The parameter set may be +examined and modified in the usual ways (typically with "epar sparams" +or ":e sparams" from the parameter editor). The parameters are +described below. +.le + +.ce +-- GENERAL PARAMETERS -- +.ls line = INDEF, nsum = 10 +The dispersion line (line or column perpendicular to the dispersion +axis) and number of adjacent lines (half before and half after unless +at the end of the image) used in finding, resizing, +editing, and tracing operations. A line of INDEF selects the middle of the +image along the dispersion axis. +.le +.ls extras = no (apsum) +Include raw unweighted and uncleaned spectra, the background spectra, and +the estimated sigmas in a three dimensional output image format. +See the discussion in the \fBapextract\fR package for further information. +.le + +.ce +-- DEFAULT APERTURE LIMITS -- +.ls lower = -3., upper = 3. (apdefault) +Default lower and upper aperture limits relative to the aperture center. +These limits are used when the apertures are first defined. +.le + +.ce +-- AUTOMATIC APERTURE RESIZING PARAMETERS -- +.ls ylevel = 0.05 (apresize) +Fraction of the peak to set aperture limits during automatic resizing. +.le + +.ce +-- TRACE PARAMETERS -- +.ls t_step = 10 (aptrace) +Step along the dispersion axis between determination of the spectrum +positions. Note the \fInsum\fR parameter is also used to enhance the +signal-to-noise at each step. +.le +.ls t_function = "spline3", t_order = 1 (aptrace) +Default trace fitting function and order. The fitting function types are +"chebyshev" polynomial, "legendre" polynomial, "spline1" linear spline, and +"spline3" cubic spline. The order refers to the number of terms in the +polynomial functions or the number of spline pieces in the spline +functions. +.le +.ls t_niterate = 1, t_low = 3., t_high = 3. (aptrace) +Default number of rejection iterations and rejection sigma thresholds. +.le + +.ce +-- APERTURE EXTRACTION PARAMETERS -- +.ls weights = "none" (apsum) (none|variance) +Type of extraction weighting. Note that if the \fIclean\fR parameter is +set then the weights used are "variance" regardless of the weights +specified by this parameter. The choices are: +.ls "none" +The pixels are summed without weights except for partial pixels at the +ends. +.le +.ls "variance" +The extraction is weighted by the variance based on the data values +and a poisson/ccd model using the \fIgain\fR and \fIreadnoise\fR +parameters. +.le +.le +.ls pfit = "fit1d" (apsum and approfile) (fit1d|fit2d) +Type of profile fitting algorithm to use. The "fit1d" algorithm is +preferred except in cases of extreme tilt. +.le +.ls lsigma = 3., usigma = 3. (apsum) +Lower and upper rejection thresholds, given as a number of times the +estimated sigma of a pixel, for cleaning. +.le + +.ce +-- DEFAULT BACKGROUND PARAMETERS -- +.ls background = "fit" (apsum) (none|average|median|minimum|fit) +Type of background subtraction. The choices are "none" for no background +subtraction, "average" to average the background within the background +regions, "median" to use the median in the background regions, "minimum" to +use the minimum in the background regions, or "fit" to fit across the +dispersion using the background within the background regions. Note that +the "average" option does not do any medianing or bad pixel checking, +something which is recommended. The fitting option is slower than the +other options and requires additional fitting parameter. +.le +.ls b_function = "legendre", b_order = 1 (apsum) +Default background fitting function and order. The fitting function types are +"chebyshev" polynomial, "legendre" polynomial, "spline1" linear spline, and +"spline3" cubic spline. The order refers to the number of +terms in the polynomial functions or the number of spline pieces in the spline +functions. +.le +.ls b_sample = "-10:-6,6:10" (apsum) +Default background sample. The sample is given by a set of colon separated +ranges each separated by either whitespace or commas. The string "*" refers +to all points. Note that the background coordinates are relative to the +aperture center and not image pixel coordinates so the endpoints need not +be integer. It is recommended that the background regions be examined +and set interactively with the 'b' key in the interactive aperture +definition mode. This requires \fIquicklook\fR to be no. +.le +.ls b_naverage = -100 (apsum) +Default number of points to average or median. Positive numbers +average that number of sequential points to form a fitting point. +Negative numbers median that number, in absolute value, of sequential +points. A value of 1 does no averaging and each data point is used in the +fit. +.le +.ls b_niterate = 1 (apsum) +Default number of rejection iterations. If greater than zero the fit is +used to detect deviant fitting points and reject them before repeating the +fit. The number of iterations of this process is given by this parameter. +.le +.ls b_low_reject = 3., b_high_reject = 3. (apsum) +Default background lower and upper rejection sigmas. If greater than zero +points deviating from the fit below and above the fit by more than this +number of times the sigma of the residuals are rejected before refitting. +.le + +.ce +-- ARC DISPERSION FUNCTION PARAMETERS -- +.ls threshold = 10. (autoidentify/identify/reidentify) +In order for a feature center to be determined the range of pixel intensities +around the feature must exceed this threshold. +.le +.ls coordlist = "linelists$idhenear.dat" (autoidentify/identify) +Arc line list consisting of an ordered list of wavelengths. +Some standard line lists are available in the directory "linelists$". +.le +.ls match = -3. (autoidentify/identify) +The maximum difference for a match between the dispersion function computed +value and a wavelength in the coordinate list. +.le +.ls fwidth = 4. (autoidentify/identify) +Approximate full base width (in pixels) of arc lines. +.le +.ls cradius = 10. (reidentify) +Radius from previous position to reidentify arc line. +.le +.ls i_function = "spline3", i_order = 1 (autoidentify/identify) +The default function and order to be fit to the arc wavelengths as a +function of the pixel coordinate. The functions choices are "chebyshev", +"legendre", "spline1", or "spline3". +.le +.ls i_niterate = 0, i_low = 3.0, i_high = 3.0 (autoidentify/identify) +Number of rejection iterations and sigma thresholds for rejecting arc +lines from the dispersion function fits. +.le +.ls refit = yes (reidentify) +Refit the dispersion function? If yes and there is more than 1 line +and a dispersion function was defined in the initial arc reference then a new +dispersion function of the same type as in the reference image is fit +using the new pixel positions. Otherwise only a zero point shift is +determined for the revised fitted coordinates without changing the +form of the dispersion function. +.le +.ls addfeatures = no (reidentify) +Add new features from a line list during each reidentification? +This option can be used to compensate for lost features from the +reference solution. Care should be exercised that misidentified features +are not introduced. +.le + +.ce +-- AUTOMATIC ARC ASSIGNMENT PARAMETERS -- +.ls select = "interp" (refspectra) +Selection method for assigning wavelength calibration spectra. +Note that an arc assignment table may be used to override the selection +method and explicitly assign arc spectra to object spectra. +The automatic selection methods are: +.ls average +Average two reference spectra without regard to any +sort or group parameters. +If only one reference spectrum is specified then it is assigned with a +warning. If more than two reference spectra are specified then only the +first two are used and a warning is given. There is no checking of the +group values. +.le +.ls following +Select the nearest following spectrum in the reference list based on the +sort and group parameters. If there is no following spectrum use the +nearest preceding spectrum. +.le +.ls interp +Interpolate between the preceding and following spectra in the reference +list based on the sort and group parameters. If there is no preceding and +following spectrum use the nearest spectrum. The interpolation is weighted +by the relative distances of the sorting parameter (see cautions in +DESCRIPTION section). +.le +.ls match +Match each input spectrum with the reference spectrum list in order. +This overrides any group values. +.le +.ls nearest +Select the nearest spectrum in the reference list based on the sort and +group parameters. +.le +.ls preceding +Select the nearest preceding spectrum in the reference list based on the +sort and group parameters. If there is no preceding spectrum use the +nearest following spectrum. +.le +.le +.ls sort = "jd" (setjd and refspectra) +Image header keyword to be used as the sorting parameter for selection +based on order. The header parameter must be numeric but otherwise may +be anything. Common sorting parameters are times or positions. +.le +.ls group = "ljd" (setjd and refspectra) +Image header keyword to be used to group spectra. For those selection +methods which use the group parameter the reference and object +spectra must have identical values for this keyword. This can +be anything but it must be constant within a group. Common grouping +parameters are the date of observation "date-obs" (provided it does not +change over a night) or the local Julian day number. +.le +.ls time = no, timewrap = 17. (refspectra) +Is the sorting parameter a 24 hour time? If so then the time origin +for the sorting is specified by the timewrap parameter. This time +should precede the first observation and follow the last observation +in a 24 hour cycle. +.le + +.ce +-- DISPERSION CORRECTION PARAMETERS -- +.ls linearize = yes (dispcor) +Interpolate the spectra to a linear dispersion sampling? If yes the +spectra will be interpolated to a linear or log linear sampling using +the linear dispersion parameters specified by other parameters. If +no the nonlinear dispersion function(s) from the dispersion function +database are assigned to the input image world coordinate system +and the spectral data is not interpolated. Note the interpolation +function type is set by the package parameter \fIinterp\fR. +.le +.ls log = no (dispcor) +Use linear logarithmic wavelength coordinates? Linear logarithmic +wavelength coordinates have wavelength intervals which are constant +in the logarithm of the wavelength. +.le +.ls flux = yes (dispcor) +Conserve the total flux during interpolation? If \fIno\fR the output +spectrum is interpolated from the input spectrum at each output +wavelength coordinate. If \fIyes\fR the input spectrum is integrated +over the extent of each output pixel. This is slower than +simple interpolation. +.le + +.ce +-- SENSITIVITY CALIBRATION PARAMETERS -- +.ls s_function = "spline3", s_order = 1 (sensfunc) +Function and order used to fit the sensitivity data. The function types +are "chebyshev" polynomial, "legendre" polynomial, "spline3" cubic spline, +and "spline1" linear spline. Order of the sensitivity fitting function. +The value corresponds to the number of polynomial terms or the number of +spline pieces. The default values may be changed interactively. +.le +.ls fnu = no (calibrate) +The default calibration is into units of F-lambda. If \fIfnu\fR = yes then +the calibrated spectrum will be in units of F-nu. +.le + +.ce +PACKAGE PARAMETERS + +The following package parameters are used by this task. The default values +may vary depending on the package. +.ls dispaxis = 2 +Default dispersion axis. The dispersion axis is 1 for dispersion +running along image lines and 2 for dispersion running along image +columns. If the image header parameter DISPAXIS is defined it has +precedence over this parameter. The default value defers to the +package parameter of the same name. +.le +.ls extinction (standard, sensfunc, calibrate) +Extinction file for a site. There are two extinction files in the +NOAO standards library, onedstds$, for KPNO and CTIO. These extinction +files are used for extinction and flux calibration. +.le +.ls caldir (standard) +Standard star calibration directory. A directory containing standard +star data files. Note that the directory name must end with '/'. +There are a number of standard star calibrations directories in the NOAO +standards library, onedstds$. +.le +.ls observatory = "observatory" (observatory) +The default observatory to use for latitude dependent computations. +If the OBSERVAT keyword in the image header it takes precedence over +this parameter. +.le +.ls interp = "poly5" (nearest|linear|poly3|poly5|spline3|sinc) (dispcor) +Spectrum interpolation type used when spectra are resampled. The choices are: + +.nf + nearest - nearest neighbor + linear - linear + poly3 - 3rd order polynomial + poly5 - 5th order polynomial + spline3 - cubic spline + sinc - sinc function +.fi +.le +.ls database = "database" +Database name used by various tasks. This is a directory which is created +if necessary. +.le +.ls verbose = no +Verbose output? If set then almost all the information written to the +logfile is also written to the terminal except when the task is a +background or batch process. +.le +.ls logfile = "logfile" +If specified detailed text log information is written to this file. +.le +.ls plotfile = "" +If specified metacode plots are recorded in this file for later review. +Since plot information can become large this should be used only if +really desired. +.le +.ih +ENVIRONMENT PARAMETERS +The environment parameter \fIimtype\fR is used to determine the extension +of the images to be processed and created. This allows use with any +supported image extension. For STF images the extension has to be exact; +for example "d1h". +.ih +DESCRIPTION +\fBDoslit\fR extracts, sky subtracts, wavelength calibrates, and flux +calibrates simple two dimensional slit spectra which have been processed to +remove the detector characteristics; i.e. CCD images have been bias, dark +count, and flat field corrected. It is primarily intended for +spectrophotometry or radial velocities of stellar spectra with the spectra +aligned with one of the image axes; i.e. the assumption is that extractions +can be done by summing along image lines or columns. The alignment does +not have to be precise but only close enough that the wavelength difference +across the spectrum profiles is insignificant. Extended objects requiring +accurate geometric alignment over many pixels are reduced using the +\fBlongslit\fR package. + +The task is a command language script which collects and combines the +functions and parameters of many general purpose tasks to provide a single, +complete data reduction path and a degree of guidance, automation, and +record keeping. In the following description and in the parameter section +the various general tasks used are identified. Further +information about those tasks and their parameters may be found in their +documentation. \fBDoslit\fR also simplifies and consolidates parameters +from those tasks and keeps track of previous processing to avoid +duplications. + +The general organization of the task is to do the interactive setup steps, +such as the reference dispersion function +determination, first using representative calibration data and then perform +the majority of the reductions automatically, possibly as a background +process, with reference to the setup data. In addition, the task +determines which setup and processing operations have been completed in +previous executions of the task and, contingent on the \fIredo\fR and +\fIupdate\fR options, skip or repeat some or all the steps. + +The description is divided into a quick usage outline followed by details +of the parameters and algorithms. The usage outline is provided as a +checklist and a refresher for those familiar with this task and the +component tasks. It presents only the default or recommended usage +since there are many variations possible. + +\fBUsage Outline\fR + +.ls 6 [1] +The images are first processed with \fBccdproc\fR for overscan, +zero level, dark count, and flat field corrections. +.le +.ls [2] +Set the \fBdoslit\fR parameters with \fBeparam\fR. Specify the object +images to be processed, +one or more arc images, and one or more standard +star images. If there are many object, arc, or standard star images +you might prepare "@ files". Set the detector and data +specific parameters. Select the processing options desired. +Finally you might wish to review the \fIsparams\fR algorithm parameters +though the defaults are probably adequate. +.le +.ls [3] +Run the task. This may be repeated multiple times with different +observations and the task will generally only do the setup steps +once and only process new images. Queries presented during the +execution for various interactive operations may be answered with +"yes", "no", "YES", or "NO". The lower case responses apply just +to that query while the upper case responses apply to all further +such queries during the current execution and no further queries of that +type will be made. +.le +.ls [4] +Apertures are defined for all the standard and object images. This is only +done if there are no previous aperture definitions for the image. +The highest peak is found and centered and the default aperture limits +are set. If the resize option is set the aperture is resized by finding +the level which is 5% (the default) of the peak above local background. +If not using the quicklook option you now have the option +of entering the aperture editing loop to check the aperture position, +size, and background fitting parameters, and possibly add additional +apertures. This is step is highly recommended. +It is important to check the background regions with the 'b' +key. To exit the background mode and then +to exit the review mode use 'q'. + +The spectrum positions at a series of points along the dispersion are +measured and a function is fit to these positions. If not using the +quicklook option the traced positions may be examined interactively and the +fitting parameters adjusted. To exit the interactive fitting type 'q'. +.le +.ls [5] +If dispersion correction is selected the first arc in the arc list is +extracted. The dispersion function is defined using the task +\fBautoidentify\fR. The \fIcrval\fR and \fIcdelt\fR parameters are used in +the automatic identification. Whether or not the automatic identification +is successful you will be shown the result of the arc line identification. +If the automatic identification is not successful identify a few arc lines +with with 'm' and use the 'l' line list identification command to +automatically add additional lines and fit the dispersion function. Check +the quality of the dispersion function fit with 'f'. When satisfied exit +with 'q'. +.le +.ls [6] +If the flux calibration option is selected the standard star spectra are +processed (if not done previously). The images are +extracted and wavelength calibrated. The appropriate arc +calibration spectra are extracted and the dispersion function refit +using the arc reference spectrum as a starting point. The standard star +fluxes through the calibration bandpasses are compiled. You are queried +for the name of the standard star calibration data file. + +After all the standard stars are processed a sensitivity function is +determined using the interactive task \fBsensfunc\fR. Finally, the +standard star spectra are extinction corrected and flux calibrated +using the derived sensitivity function. +.le +.ls [7] +The object spectra are now automatically +extracted, wavelength calibrated, and flux calibrated. +.le +.ls [8] +The option to examine the final spectra with \fBsplot\fR may be given. +To exit type 'q'. In quicklook mode the spectra are plotted +noninteractively with \fBbplot\fR. +.le +.ls [9] +The final spectra will have the same name as the original 2D images +with a ".ms" extension added. +.le + +\fBSpectra and Data Files\fR + +The basic input consists of two dimensional slit object, standard star, and +arc calibration spectra stored as IRAF images. +The type of image format is defined by the +environment parameter \fIimtype\fR. Only images with that extension will +be processed and created. +The raw CCD images must be +processed to remove overscan, bias, dark count, and flat field effects. +This is generally done using the \fBccdred\fR package. Lines of constant +wavelength should be closely aligned with one of the image axes though a +small amount of misalignment only causes a small loss of resolution. For +large misalignments one may use the \fBrotate\fR task. More complex +geometric problems and observations of extended objects should be handled +by the \fBlongslit\fR package. + +The arc +spectra are comparison arc lamp observations (they must all be of the same +type). The assignment of arc calibration exposures to object exposures is +generally done by selecting the nearest in time and interpolating. +However, the optional \fIarc assignment table\fR may be used to explicitly +assign arc images to specific objects. The format of this file is +described in task \fBrefspectra\fR. + +The final reduced spectra are recorded in one, two or three dimensional IRAF +images. The images have the same name as the original images with an added +".ms" extension. Each line in the reduced image is a one dimensional +spectrum with associated aperture, wavelength, and identification +information. With a single aperture the image will be one dimensional +and with multiple apertures the image will be two dimensional. +When the \fIextras\fR parameter is set the images will be three +dimensional (regardless of the number of apertures) and the lines in the +third dimension contain additional information (see +\fBapsum\fR for further details). These spectral formats are accepted by the +one dimensional spectroscopy tasks such as the plotting tasks \fBsplot\fR +and \fBspecplot\fR. + +\fBPackage Parameters\fR + +The package parameters set parameters which change +infrequently and set the standard I/O functions. The extinction file +is used for making extinction corrections and the standard star +calibration directory is used for determining flux calibrations from +standard star observations. The calibration directories contain data files +with standard star fluxes and band passes. The available extinction +files and flux calibration directories may be listed using the command: +.nf + + cl> help onedstds + +.fi + +The extinction correction requires computation of an air mass using the +task \fBsetairmass\fR. The air mass computation needs information +about the observation and, in particular, the latitude of the observatory. +This is determined using the OBSERVAT image header keyword. If this +keyword is not present the observatory parameter is used. See the +task \fBobservatory\fR for more on defining the observatory parameters. + +The spectrum interpolation type is used whenever a spectrum needs to be +resampled for linearization or performing operations between spectra +with different sampling. The "sinc" interpolation may be of interest +as an alternative but see the cautions given in \fBonedspec.package\fR. + +The general direction in which the spectra run is specified by the +dispersion axis parameter. Recall that ideally it is the direction +of constant wavelength which should be aligned with an image axis and +the dispersion direction may not be exactly aligned because atmospheric +dispersion. + +The verbose parameter selects whether to print everything which goes +into the log file on the terminal. It is useful for monitoring +what the \fBdoslit\fR task does. The log and plot files are useful for +keeping a record of the processing. A log file is highly recommended. +A plot file provides a record of the apertures, traces, and extracted +spectra but can become quite large. +The plotfile is most conveniently viewed and printed with \fBgkimosaic\fR. + +\fBProcessing Parameters\fR + +The input images are specified by image lists. The lists may be +a list of explicit comma separate image names, @ files, or image +templates using pattern matching against file names in the directory. +To allow wildcard image lists to be used safely and conveniently the +image lists are checked to remove extracted images (the .ms images) +and to automatically identify object and arc spectra. Object and arc +images are identified by the keyword IMAGETYP with values of "object", +"OBJECT", "comp", or "COMPARISON" (the current practice at NOAO). +If arc images are found in the object list they are transferred to the +arc list while if object images are found in the arc list they are ignored. +All other image types, such as biases, darks, or flat fields, are +ignored. This behavior allows simply specifying all images with a wildcard +in the object list with automatic selections of arc spectra or a +wildcard in the arc list to automatically find the arc spectra. +If the data lack the identifying information it is up to the user +to explicitly set the proper lists. + +The arc assignment table is a file which may be used to assign +specific arc spectra to specific object and standard star spectra. +For more on this option see \fBrefspectra\fR. + +The next set of parameters describe the noise characteristics and +spectrum characteristics. The read out noise and gain are used when +"cleaning" cosmic rays and when using variance or optimal weighting. These +parameters must be fairly accurate. Note that these are the effective +parameters and must be adjusted if previous processing has modified the +pixel values; such as with an unnormalized flat field. +The variance +weighting and cosmic-ray cleanning are sensitive to extremely strong +cosmic-rays; ones which are hundreds of times brighter than the +spectrum. The \fIdatamax\fR is used to set an upper limit for any +real data. Any pixels above this value will be flagged as cosmic-rays +and will not affect the extractions. + +The profile width should be approximately the full width +at the profile base. This parameter is used for centering and tracing +of the spectrum profiles. + +The approximate central wavelength and dispersion are used for the +automatic identification of the arc reference. They may be specified +as image header keywords or values. The INDEF values search the +entire range of the coordinate reference file but the automatic +line identification algorithm works much better and faster if +approximate values are given. + +The next set of parameters select the processing steps and options. The +various calibration steps may be done simultaneously, that is at the same +time as the basic extractions, or in separate executions of the task. +Typically, all the desired operations are done at the same time. +Dispersion correction requires at least one arc spectrum and flux +calibration requires dispersion correction and at least one standard star +observation. + +The \fIresize\fR option resets the edges of the extraction aperture based +on the profile for each object and standard star image. The default +resizing is to the 5% point relative to the peak measured above the +background. This allows following changes in the seeing. However, one +should consider the consequences of this if attempting to flux calibrate +the observations. Except in quicklook mode, the apertures for each object +and standard star observation may be reviewed graphically and +adjustments made to the aperture width and background regions. + +The \fIclean\fR option invokes a profile +fitting and deviant point rejection algorithm as well as a variance weighting +of points in the aperture. See the next section for more about +requirements to use this option. + +Generally once a spectrum has been processed it will not be reprocessed if +specified as an input spectrum. However, changes to the underlying +calibration data can cause such spectra to be reprocessed if the +\fIupdate\fR flag is set. The changes which will cause an update are a +new arc reference image and new standard stars. If all input spectra are to be +processed regardless of previous processing the \fIredo\fR flag may be +used. Note that reprocessing clobbers the previously processed output +spectra. + +The final step is to plot the spectra if the \fIsplot\fR option is +selected. In non-quicklook mode there is a query which may be +answered either in lower or upper case. The plotting uses the interactive +task \fBsplot\fR. In quicklook mode the plot appears noninteractively +using the task \fBbplot\fR. + +The \fIquicklook\fR option provides a simpler, less interactive, mode. +In quicklook mode a single aperture is defined using default parameters +without interactive aperture review or trace fitting and +the \fIsplot\fR option selects a noninteractive plot to be +shown at the end of processing of each object and standard star +spectrum. While the algorithms used in quicklook mode are nearly the same +as in non-quicklook mode and the final results may be the same it is +recommended that the greater degree of monitoring and review in +non-quicklook mode be used for careful final reductions. + +The batch processing option allows object spectra to be processed as a +background or batch job. This will occur only if the interactive +\fIsplot\fR option is not active; either not set, turned off during +processing with "NO", or in quicklook mode. In batch processing the +terminal output is suppressed. + +The \fIlistonly\fR option prints a summary of the processing steps +which will be performed on the input spectra without actually doing +anything. This is useful for verifying which spectra will be affected +if the input list contains previously processed spectra. The listing +does not include any arc spectra which may be extracted to dispersion +calibrate an object spectrum. + +The last parameter (excluding the task mode parameter) points to +another parameter set for the algorithm parameters. The default +parameter set is called \fIsparams\fR. The algorithm parameters are +discussed further in the next section. + +\fBAlgorithms and Algorithm Parameters\fR + +This section summarizes the various algorithms used by the +\fBdoslit\fR task and the parameters which control and modify the +algorithms. The algorithm parameters available to you are +collected in the parameter set \fBsparams\fR. These parameters are +taken from the various general purpose tasks used by the \fBdoslit\fR +processing task. Additional information about these parameters and +algorithms may be found in the help for the actual +task executed. These tasks are identified below. The aim of this +parameter set organization is to collect all the algorithm parameters +in one place separate from the processing parameters and include only +those which are relevant for slit data. The parameter values +can be changed from the defaults by using the parameter editor, +.nf + +cl> epar sparams + +.fi +or simple typing \fIsparams\fR. +The parameter editor can also be entered when editing the \fBdoslit\fR +parameters by typing \fI:e\fR when positioned at the \fIsparams\fR +parameter. + +\fBAperture Definitions\fR + +The first operation is to define the extraction apertures, which include the +aperture width, background regions, and position dependence with +wavelength, for the input slit spectra and, if flux calibration is +selected, the standard star spectra. This is done only for spectra which +do not have previously defined apertures unless the \fIredo\fR option is +set to force all definitions to be redone. Thus, apertures may be +defined separately using the \fBapextract\fR tasks. This is particularly +useful if one needs to use reference images to define apertures for very +weak spectra which are not well centered or traced by themselves. + +Initially a single spectrum is found and a default aperture defined +automatically. If the \fIresize\fR parameter is set the aperture width is +adjusted to a specified point on the spectrum profile (see +\fBapresize\fR). If not in "quicklook" mode (set by the \fIquicklook\fR +parameter) a query is printed to select whether to inspect and modify the +aperture and background aperture definitions using the commands described +for \fBapedit\fR. This option allows adding +apertures for other objects on the slit and adjusting +background regions to avoid contaminating objects. The query may be +answered in lower case for a single spectrum or in upper case to +permanently set the response for the duration of the task execution. This +convention for query responses is used throughout the task. It is +recommended that quicklook only be used for initial quick extractions and +calibration and that for final reductions one at least review the aperture +definitions and traces. + +The initial spectrum finding and aperture definitions are done at a specified +line or column. The positions of the spectrum at a set of other lines or +columns is done next and a smooth function is fit to define the aperture +centers at all points in the image. In non-quicklook mode the user has the +option to review and adjust the function fitting parameters and delete bad +position determinations. As with the initial aperture review there is a +query which may be answered either in lower or upper case. + +The above steps are all performed using tasks from the \fBapextract\fR +package and parameters from the \fBsparams\fR parameters. As a quick +summary, the dispersion direction of the spectra are determined from the +package \fBdispaxis\fR parameter if not defined in the image header. The default +line or column for finding the object position on the slit and the number +of image lines or columns to sum are set by the \fIline\fR and \fInsum\fR +parameters. A line of INDEF (the default) selects the middle of the image. +The automatic finding algorithm is described for the task +\fBapfind\fR and is basically finds the strongest peak. The default +aperture size, background parameters, and resizing are described in +the tasks \fBapdefault\fR and \fBapresize\fR and the +parameters used are also described there. +The tracing is done as described in \fBaptrace\fR and consists of +stepping along the image using the specified \fIt_step\fR parameter. The +function fitting uses the \fBicfit\fR commands with the other parameters +from the tracing section. + +\fBExtraction\fR + +The actual extraction of the spectra is done by summing across the +fixed width apertures at each point along the dispersion. +The default is to simply sum the pixels using +partial pixels at the ends. There is an option to weight the +sum based on a Poisson variance model using the \fIreadnoise\fR and +\fIgain\fR detector parameters. Note that if the \fIclean\fR +option is selected the variance weighted extraction is used regardless +of the \fIweights\fR parameter. The sigma thresholds for cleaning +are also set in the \fBsparams\fR parameters. + +The cleaning and variance weighting options require knowing the effective +(i.e. accounting for any image combining) read out noise and gain. These +numbers need to be adjusted if the image has been processed such that the +intensity scale has a different origin (such as applying a separate +background subtraction operation) or scaling (such as caused by +unnormalized flat fielding). These options also require using background +subtraction if the profile does not go to zero. For optimal extraction and +cleaning to work it is recommended that any flat fielding be done using +normalized flat fields (as is done in \fBccdproc\fR) and using background +subtraction if there is any appreciable sky. For further discussion of +cleaning and variance weighted extraction see \fBapvariance\fR and +\fBapprofiles\fR as well as \fBapsum\fR. + +Background sky subtraction is done during the extraction based on +background regions and parameters defined by the default parameters or +changed during the interactive setting of the apertures. The background +subtraction options are to do no background subtraction, subtract the +average, median, or minimum of the pixels in the background regions, or to +fit a function and subtract the function from under the extracted object +pixels. The background regions are specified in pixels from +the aperture center and follow changes in center of the spectrum along the +dispersion. The syntax is colon separated ranges with multiple ranges +separated by a comma or space. The background fitting uses the \fBicfit\fR +routines which include medians, iterative rejection of deviant points, and +a choice of function types and orders. Note that it is important to use a +method which rejects cosmic rays such as using either medians over all the +background regions (\fIbackground\fR = "median") or median samples during +fitting (\fIb_naverage\fR < -1). The background subtraction algorithm and +options are described in greater detail in \fBapsum\fR and +\fBapbackground\fR. + +\fBDispersion Correction\fR + +If dispersion correction is not selected, \fIdispcor\fR=no, then the object +spectra are simply extracted. The extracted spectra may be plotted +by setting the \fIsplot\fR option. This produces a query and uses +the interactive \fBsplot\fR task in non-quicklook mode and uses the +noninteractive \fBbplot\fR task in quicklook mode. + +Dispersion corrections are applied to the extracted spectra if the +\fIdispcor\fR processing parameter is set. There are three basic steps +involved; determining the dispersion functions relating pixel position to +wavelength, assigning the appropriate dispersion function to a particular +observation, and either storing the nonlinear dispersion function in the +image headers or resampling the spectra to evenly spaced pixels in +wavelength. + +The first arc spectrum in the arc list is used to define the reference +dispersion solution. It is extracted at middle of the image with no +tracing. Note extractions of arc spectra are not background subtracted. +The task \fBautoidentify\fR is attempts to define the dispersion function +automatically using the \fIcrval\fR and \fIcdelt\fR parameters. Whether or +not it is successful the user is presented with the interactive +identification graph. The automatic identifications can be reviewed and a +new solution or corrections to the automatic solution may be performed. + +The arc dispersion function parameters are for \fBautoidentify\fR and it's +related partner \fBreidentify\fR. The parameters define a line list for +use in automatically assigning wavelengths to arc lines, a centering width +(which should match the line widths at the base of the lines), the +dispersion function type and orders, parameters to exclude bad lines from +function fits, and defining whether to refit the dispersion function as +opposed to simply determining a zero point shift. The defaults should +generally be adequate and the dispersion function fitting parameters may be +altered interactively. One should consult the help for the two tasks for +additional details of these parameters and the interactive operation of +\fBautoidentify\fR. + +The extracted reference arc spectrum is then dispersion corrected. +If the spectra are to be linearized, as set by the \fIlinearize\fR +parameter, the default linear wavelength parameters are printed and +you have the option to adjust them. The dispersion system defined at +this point will be applied automatically to all other spectra as they +are dispersion corrected. + +Once the reference dispersion function is defined other arc spectra are +extracted as required by the object spectra. The assignment of arcs is +done either explicitly with an arc assignment table (parameter +\fIarctable\fR) or based on a header parameter such as a time. +This assignments are made by the task +\fBrefspectra\fR. When two arcs are assigned to an object spectrum an +interpolation is done between the two dispersion functions. This makes an +approximate correction for steady drifts in the dispersion. + +The tasks \fBsetjd\fR and \fBsetairmass\fR are automatically run on all +spectra. This computes and adds the header parameters for the Julian date +(JD), the local Julian day number (LJD), the universal time (UTMIDDLE), and +the air mass at the middle of the exposure. The default arc assignment is +to use the Julian date grouped by the local Julian day number. The +grouping allows multiple nights of data to be correctly assigned at the +same time. + +The assigned arc spectra are then extracted using the object aperture +definitions (but without background subtraction or cleaning) so that the +same pixels on the detector are used. The extracted arc spectra are then +reidentified automatically against the reference arc spectrum. Some +statistics of the reidentification are printed (if not in batch mode) and +the user has the option of examining the lines and fits interactively if +not in quicklook mode. The task which does the reidentification is called +\fBreidentify\fR. + +The last step of dispersion correction is setting the dispersion +of the object image from the arc images. There are two choices here. +If the \fIlinearize\fR parameter is not set the nonlinear dispersion +function is stored in the image header. Other IRAF tasks interpret +this information when dispersion coordinates are needed for plotting +or analysis. This has the advantage of not requiring the spectra +to be interpolated and the disadvantage that the dispersion +information is only understood by IRAF tasks and cannot be readily +exported to other analysis software. + +If the \fIlinearize\fR parameter is set then the spectra are resampled to a +linear dispersion relation either in wavelength or the log of the +wavelength using the dispersion coordinate system defined previously +for the arc reference spectrum. + +The linearization algorithm parameters allow selecting the interpolation +function type, whether to conserve flux per pixel by integrating across the +extent of the final pixel, and whether to linearize to equal linear or +logarithmic intervals. The latter may be appropriate for radial velocity +studies. The default is to use a fifth order polynomial for interpolation, +to conserve flux, and to not use logarithmic wavelength bins. These +parameters are described fully in the help for the task \fBdispcor\fR which +performs the correction. + +\fBFlux Calibration\fR + +Flux calibration consists of an extinction correction and an instrumental +sensitivity calibration. The extinction correction only depends on the +extinction function defined by the package parameter \fIextinct\fR and +determination of the airmass from the header parameters (the air mass is +computed by \fBsetairmass\fR as mentioned earlier). The sensitivity +calibration depends on a sensitivity calibration spectrum determined from +standard star observations for which there are tabulated absolute fluxes. +The task that applies both the extinction correction and sensitivity +calibration to each extracted object spectrum is \fBcalibrate\fR. Consult +the manual page for this task for more information. + +Generation of the sensitivity calibration spectrum is done before +processing any object spectra since it has two interactive steps and +requires all the standard star observations. The first step is tabulating +the observed fluxes over the same bandpasses as the calibrated absolute +fluxes. The standard star tabulations are done after each standard star is +extracted and dispersion corrected. You are asked for the name of the +standard star as tabulated in the absolute flux data files in the directory +\fIcaldir\fR defined by the package parameters. +The tabulation of the standard star +observations over the standard bandpasses is done by the task +\fBstandard\fR. The tabulated data is stored in the file \fIstd\fR. Note +that if the \fIredo\fR flag is not set any new standard stars specified in +subsequent executions of \fBdoslit\fR are added to the previous data in +the data file, otherwise the file is first deleted. Modification of the +tabulated standard star data, such as by adding new stars, will cause any +spectra in the input list which have been previously calibrated to be +reprocessed if the \fIupdate\fR flag is set. + +After the standard star calibration bandpass fluxes are tabulated the +information from all the standard stars is combined to produce a +sensitivity function for use by \fBcalibrate\fR. The sensitivity function +determination is interactive and uses the task \fBsensfunc\fR. This task +allows fitting a smooth sensitivity function to the ratio of the observed +to calibrated fluxes verses wavelength. The types of manipulations one +needs to do include deleting bad observations, possibly removing variable +extinction (for poor data), and possibly deriving a revised extinction +function. This is a complex operation and one should consult the manual +page for \fBsensfunc\fR. The sensitivity function is saved as a one +dimensional spectrum with the name \fIsens\fR. Deletion of this image +will also cause reprocessing to occur if the \fIupdate\fR flag is set. +.ih +EXAMPLES +1. The following example uses artificial data and may be executed +at the terminal (with IRAF V2.10). This is similar to the sequence +performed by the test procedure "demos doslit". The output is with +the verbose package parameter set. Normally users use \fBeparam\fR +rather than the long command line. All parameters not shown +for \fBsparams\fR and \fBdoslit\fR are the default. + +.nf +cl> demos mkdoslit +Creating example longslit in image demoarc1 ... +Creating example longslit in image demoobj1 ... +Creating example longslit in image demostd1 ... +Creating example longslit in image demoarc2 ... +cl> doslit demoobj1 arcs=demoarc1,demoarc2 stand=demostd1 \ +>>> extcor=yes, fluxcal=yes resize=yes +Searching aperture database ... +Finding apertures ... +Jan 17 15:52: FIND - 1 apertures found for demoobj1 +Resizing apertures ... +Jan 17 15:52: APRESIZE - 1 apertures resized for demoobj1 (-3.50, 3.49) +Edit apertures for demostd1? (yes): + +Fit traced positions for demostd1 interactively? (yes): +Tracing apertures ... +Fit curve to aperture 1 of demostd1 interactively (yes): + +Searching aperture database ... +Finding apertures ... +Jan 17 15:54: FIND - 1 apertures found for demostd1 +Resizing apertures ... +Jan 17 15:54: APRESIZE - 1 apertures resized for demostd1 (-3.35, 3.79) +Edit apertures for demostd1? (yes): + +Fit traced positions for demostd1 interactively? (yes): n +Tracing apertures ... +Jan 17 15:55: TRACE - 1 apertures traced in demostd1. +Jan 17 15:55: DATABASE - 1 apertures for demostd1 written to database +Extract arc reference image demoarc1 +Searching aperture database ... +Finding apertures ... +Jan 17 15:55: FIND - 1 apertures found for demoarc1 +Jan 17 15:55: DATABASE - 1 apertures for demoarc1 written to database +Extracting apertures ... +Jan 17 15:55: EXTRACT - Aperture 1 from demoarc1 --> demoarc1.ms +Determine dispersion solution for demoarc1 + + + + + +demoarc1.ms.imh: w1 = 4204.18..., w2 = 7355.37..., dw = 6.16..., nw = 512 + Change wavelength coordinate assignments? (yes|no|NO) (no): n +Extract standard star spectrum demostd1 +Searching aperture database ... +Jan 17 15:59: DATABASE - 1 apertures read for demostd1 from database +Extracting apertures ... +Jan 17 15:59: EXTRACT - Aperture 1 from demostd1 --> demostd1.ms +Assign arc spectra for demostd1 +[demostd1] refspec1='demoarc1 0.403' +[demostd1] refspec2='demoarc2 0.597' +Extract and reidentify arc spectrum demoarc1 +Searching aperture database ... +Jan 17 15:59: DATABASE - 1 apertures read for demostd1 from database +Jan 17 15:59: DATABASE - 1 apertures for demoarc1 written to database +Extracting apertures ... +Jan 17 15:59: EXTRACT - Aperture 1 from demoarc1 --> demostd1demoarc1.ms + +REIDENTIFY: NOAO/IRAF V2.10BETA valdes@puppis Fri 15:59:21 17-Jan-92 + Reference image = demoarc1.ms, New image = demostd1..., Refit = yes +Image Data Found Fit Pix Shift User Shift Z Shift RMS +demo... 48/48 48/48 2.22E-4 0.00184 5.09E-7 0.225 +Fit dispersion function interactively? (no|yes|NO|YES) (yes): +demoarc1.ms: w1 = 4211.81, w2 = 7353.58, dw = 6.148, nw = 512, log = no + Change wavelength coordinate assignments? (yes|no|NO): N +demo... 48/48 48/48 2.22E-4 0.00184 5.09E-7 0.225 +Extract and reidentify arc spectrum demoarc2 +Searching aperture database ... +Jan 17 16:01: DATABASE - 1 apertures read for demostd1 from database +Jan 17 16:01: DATABASE - 1 apertures for demoarc2 written to database +Extracting apertures ... +Jan 17 16:01: EXTRACT - Aperture 1 from demoarc2 --> demostd1demoarc2.ms + +REIDENTIFY: NOAO/IRAF V2.10BETA valdes@puppis Fri 16:01:54 17-Jan-92 + Reference image = demoarc1.ms, New image = demostd1..., Refit = yes +Image Data Found Fit Pix Shift User Shift Z Shift RMS +demo... 48/48 48/48 0.00302 0.0191 3.82E-6 0.244 +Dispersion correct demostd1 +demostd1.ms: ap = 1, w1 = 4204.181, w2 = 7355.375, dw = 6.16..., nw = 512 +Compile standard star fluxes for demostd1 +Star name in calibration list: hz2 +demostd1.ms.imh[1]: Example artificial long slit image +Compute sensitivity function +Fit aperture 1 interactively? (no|yes|NO|YES) (no|yes|NO|YES) (yes): + +Sensitivity function for all apertures --> sens +Flux and/or extinction calibrate standard stars +[demostd1.ms.imh][1]: Example artificial long slit image + Extinction correction applied + Flux calibration applied +Extract object spectrum demoobj1 +Searching aperture database ... +Jan 17 16:05: DATABASE - 1 apertures read for demoobj1 from database +Extracting apertures ... +Jan 17 16:05: EXTRACT - Aperture 1 from demoobj1 --> demoobj1.ms +Assign arc spectra for demoobj1 +[demoobj1] refspec1='demoarc1 0.403' +[demoobj1] refspec2='demoarc2 0.597' +Extract and reidentify arc spectrum demoarc1 +Searching aperture database ... +Jan 17 16:05: DATABASE - 1 apertures read for demoobj1 from database +Jan 17 16:05: DATABASE - 1 apertures for demoarc1 written to database +Extracting apertures ... +Jan 17 16:05: EXTRACT - Aperture 1 from demoarc1 --> demoobj1demoarc1.ms + +REIDENTIFY: NOAO/IRAF V2.10BETA valdes@puppis Fri 16:05:39 17-Jan-92 + Reference image = demoarc1.ms, New image = demoobj1..., Refit = yes +Image Data Found Fit Pix Shift User Shift Z Shift RMS +demo... 48/48 48/48 -2.49E-4 -0.00109 -1.1E-7 0.227 +Extract and reidentify arc spectrum demoarc2 +Searching aperture database ... +Jan 17 16:05: DATABASE - 1 apertures read for demoobj1 from database +Jan 17 16:05: DATABASE - 1 apertures for demoarc2 written to database +Extracting apertures ... +Jan 17 16:05: EXTRACT - Aperture 1 from demoarc2 --> demoobj1demoarc2.ms + +REIDENTIFY: NOAO/IRAF V2.10BETA valdes@puppis Fri 16:05:42 17-Jan-92 + Reference image = demoarc1.ms, New image = demoobj1..., Refit = yes +Image Data Found Fit Pix Shift User Shift Z Shift RMS +demo... 48/48 48/48 0.00266 0.0169 3.46E-6 0.24 +Dispersion correct demoobj1 +demoobj1.ms: ap = 1, w1 = 4204.181, w2 = 7355.375, dw = 6.16..., nw = 512 +Extinction correct demoobj1 +Flux calibrate demoobj1 +[demoobj1.ms.imh][1]: Example artificial long slit image + Extinction correction applied + Flux calibration applied +.fi + +2. To redo the above: + +.nf +cl> doslit demoobj1 arcs=demoarc1,demoarc2 stand=demostd1 \ +>>> extcor=yes, fluxcal=yes resize=yes redo+ +.fi +.ih +REVISIONS +.ls DOSLIT V2.11 +The initial arc line identifications is done with the automatic line +identification algorithm. +.le +.ls DOSLIT V2.10.3 +The usual output WCS format is "equispec". The image format type to be +processed is selected with the \fIimtype\fR environment parameter. The +dispersion axis parameter is now a package parameter. Images will only +be processed if the have the CCDPROC keyword. A \fIdatamax\fR parameter +has been added to help improve cosmic ray rejection. The arc reference +is no longer taken from the center of the image but using the first object +aperture. A bug which alphabetized the arc list was fixed. +.le +.ih +SEE ALSO +apbackground, apedit, apfind, approfiles, aprecenter, apresize, apsum, +aptrace, apvariance, calibrate, ccdred, center1d, ctioslit, dispcor, +echelle.doecslit, icfit, autoidentify, identify, kpnocoude, kpnoslit, +specred, observatory, onedspec.package, refspectra, reidentify, sensfunc, +setairmass, setjd, splot, standard +.endhelp -- cgit