Provided by: gcx_1.3-1.1build1_amd64 bug


       gcx - astronomical image processing and photometry


       gcx [options] [files...]


       gcx  is  an  astronomical  image  processing  and data reduction tool, with an easy to use
       graphical user interface.  It provides a complete set of data reduction functions for  CCD
       photometry,  with frame WCS fitting, automatic star identification, aperture photometry of
       target and standard stars, single-frame ensemble photometry solution finding,  multi-frame
       color coefficient fitting, extinction coefficient fitting, and all-sky photometry, as well
       as general-purpose astronomical  image  processing  functions  (bias,  dark,  flat,  frame
       alignment and stacking); It can function as a FITS viewer.

       For  automating  data  reduction  of large numbers of frames, gcx implements recipe files.
       These files contain specific information about the objects measured in each field. Once  a
       recipe  file  is  created  for  a  given  field, any number of frames of that field can be
       reduced without user intervention.

       The program can control CCD cameras and telescopes, and  implement  automatic  observation
       scripting.  Cameras  are  controlled  through  a  hardware-specific  server,  to which gcx
       connects through  a  TCP  socket.  It  generates  FITS  files  with  comprehensive  header

       Telescopes  and  mounts  using  the  LX200 protocol are supported. gcx uses it's automatic
       field identification functions to refine telecope pointing accuracy.


       When invoked without arguments, the program runs in GUI  mode.  Most  functions  are  also
       accessible through command line options, descibed below.

       -h, --help
              Print command line options.

              Print all the on-line help on stdout.

              Print program version.

       -D, --debug <level>
              Set debug level to <level>; 0=quiet, 4=noisy.

       -o, --output <file_name>
              Set output file name for import, convert and frame operations.

       -r, --rcfile <config_file>
              Load configuration file.

       -S, --set <option>=<value>
              Set the value of an option overriding the configuration file.

       -i, --interactive
              Force display frames as they are being processed.

Observation Scripting, Photometry and File Conversion Options

       -p, --recipe <recipe_file>
              Load recipe file (searches rcp_path).

       -P, --phot-run <recipe_file>
              Load recipe file and run photometry in batch mode. Report in native format.

       -V, --phot-run-aavso <recipe_file>
              Load recipe file and run photometry in batch mode. Report in AAVSO format.

       If  <recipe_file>  is  set  to  one of the following three special tokens, the recipe will
       change depeding on information in the frame header:

              will create a recipe on-the-fly from Tycho catalog data (if available);

              will search the recipe path for a file with the same name  as  the  object  in  the
              frame (ending in .rcp);

       _AUTO_ will  search  for a recipe by object name, and if that is not found, create a tycho

       --import <catalog name>
              Convert a tabular catalog file to the gcx Lisp-like format. Reads  stdin.   Current
              table formats are: gcvs, gcvs-pos, landolt, henden, sumner.

       --merge <recipe_file>
              Merge  a  new  recipe file over the one loaded with the --recipe option. Checks are
              made for either positional or name duplicates.  Only stars brighter than  mag_limit
              are merged.

              Specify  a  target  object  to  be  merged into a recipe file. It will also set the
              recipe object, ra and dec fields.

       --make-tycho-rcp <radius>
              Create a recipe file for the object specified with --object using  tycho2 stars  in
              a box radius arcminutes around the object.

       --rcp-to-aavso <recipe_file>
              Convert a recipe file to the aavso db (tab-delimited) format.  If the file argument
              is '-', stdin is read.  The recipe comment and star comment fields are  interpreted
              to get some db fields.  See the --help-all output for more info.

       -T, --rep-to-table <report_file>
              Convert  a  report file to tabular format.  If an output file name is not specified
              (with the '-o' argument), stdout is used.  If the file argument is  '-',  stdin  is
              read.   The  format  of the table is specified by the value of the .file.tab_format
              option, see below.

       -O, --obsfile <obs_file>
              Load/run observation scripting file (searches obs_path).

       -n, --to-pnm
              Convert a fits file to 8-bit pnm.  If an output file name is  not  specified  (with
              the '-o' argument), stdout is used.

       -j, --object
              Specify  a target object (useful for setting an initial wcs when there isn't enough
              information present in the fits headers).

              Set a magnitude limit for the output of import and merge commands.

CCD Reduction Options

       -d, --dark <dark_frame>
              Set the dark frame / do dark subtraction.

       -b, --bias <bias_frame>
              Set the bias frame / do bias subtraction.

       -f, --flat <flat_frame>
              Set the flat field frame / flatfield.

       -G, --gaussian-blur <fwhm>
              Set blur FWHM / apply Gaussian blur.

       -a, --align <align_ref_frame>
              Set the alignment reference frame / align frames.

       -A, --add-bias <bias>
              Set the value of a constant bias to add to all frames / add a bias to frames.

       -M, --multiply <multiplier>
              Set a constant to multiply all frames with / multiply frames by a scalar.

       Multiplication is performed before addition.

       -u, --update-file
              Save reduction results overwriting the original files.

       -s, --stack
              Stack the frames using the method set in the configration file;  for  some  methods
              additive background alignment is performed.

       -F, --superflat
              Stack the frames using an multiplicative background alignment procedure; the frames
              should be already dark-substracted.

       -N, --no-reduce
              Do not run the reduction operations, just load the frame list / reduction options.

       When any of the CCD reduction options is set  and  the  -i  flag  is  not  specified,  the
       reduction  operations are run in batch mode on all the supplied fits files. When no output
       file is specified or -i is set, the files are loaded into the batch processing file  list,
       the reduction options set in the dialog, and the program starts up in gui mode

Report Converter Format String

       The report converter option converts the native gcx output to a fixed-width tabular format
       that is easy to import in other programs for further processing.  The  table's  format  is
       defined  by  the  .file.tab_format  configuration  option.   The option string consists of
       tokens separated by spaces.  There are two types of  tokens:  option  tokens,  and  column

       Options  tokens  set  global  table  options when present. They can appear anywhere in the
       format string.

              Generate a table header line containing the column titles.

              Generate a list of columns with position information at the start of the output.

              Generate a line with descriptive statistics on the stars' residuals at the  end  of
              each frame.

       Column tokens specify what information gets output in each column.  The first column token
       corresponds to the first output column,  and  so  on  in  order.  Each  column  token  can
       optionally  be  followed by a specifier of the form: width.precision. The width excludes a
       single character spacer between the columns. Supported colum tokens are:

       name [w]
              Output the star's designator.

       ra [w] Output the right ascension in h:m:s format.

       dra [w.p]
              Output the right ascension in decimal degrees format.

       dec [w]
              Output the declination in d:m:s format.

       ddec [w.p]
              Output the declination in decimal degrees format.

       smag [w.p] <band>
              Output the standard magnitude with the given name.

       serr [w.p] <band>
              Output the error of the standard magnitude with the given name.

       imag [w.p] <band>
              Output the instrumental magnitude with the given name.

       ierr [w.p] <band>
              Output the error of the instrumental magnitude with the given name.

       flags [w]
              Output reduction flags and the star type.

       observation [w]
              Output the name of the observation (a synthetic name that  can  be  used  to  group
              stars reduced from the same frame.

       airmass [w.p]
              Output the airmass of the observation.

       jdate [w.p]
              Output the Julian date of the observation.

       mjd [w.p]
              Output the modified Julian date of the observation.

       filter [w]
              Output the filter name used for the observation.

       xc/yc [w.p]
              Output the frame coordintes of the star's centroid.

       xerr/yerr [w.p]
              Output the estimated centroiding errors.

       dx/dy [w.p]
              Output  the amount the star was moved from it's catalog position when the measuring
              aperture was centered.

       residual [w.p]
              Output the star's residual in the ensemble solution.

       stderr [w.p]
              Output the star's standard error (residual divided by the estimated error).

       Fields for which data is not available are left blank.

Image Navigation and Object Selection

       Middle click or space bar
              Pan cursor.

       '='    Zoom in around cursor.

       '-'    Zoom out.

       Left button drag left/right
              Adjust brightness.

       Left button drag up/down
              Adjust contrast,

       0      Auto scale intensity.

       9      Scale Min-Max.

       1-8    Auto scale with different intensity spans 1 is sharpest, 8 is dullest.

       Left click on an object
              Select object (and deselect all others).

       Shift-left click on an object
              Add to selection.

       Ctrl-left click on a star image
              Mark star (if not too faint).

       Left click on image
              Show local image statistics.

       Right click on image
              Pop-up the main menu.

       Right click on an object
              Pop-up the star menu.

       Many useful commands have keyboard accelerators; they are displayed in the menus.


       The native image file format of gcx is FITS. The program  will  read  16-bit  integer  and
       32-bit  float  files  (BITPIX  =  16  or BITPIX = -32), and save 16-bit integer files. The
       internal representation of images is in 32-bit floating point.

       gcx supports transparent compression and decompression of fits files when  zcat and   gzip
       are available and their path is set in the corresponding options.

       Configuration  options  are  stored in ~/.gcxrc. The options can be edited in GUI mode, or
       directly in the file itself. A template configuration file can  be  created  by  selecting
       "save" in the option editing dialog.

       The  program  reads several object catalog formats. See the relevant chapter in the User's
       manual for information on how to set up catalogs.   Catalogs  are  normally  placed  under

       Documentation  files  usually reside in the "docs" directory of the source distribution or
       in  /usr/share/doc/gcx.

       Example data is distributed separately from  the  main  source.   When  installed  from  a
       package it usually goes to /usr/share/doc/gcx/examples.


       GCX UserĀ“s Manual; gnuplot(1); gzip(1); zcat(1); README.vizquery.


       gcx  was  written  by  Radu  Corlan, with valuable contributions from Alexandru Dan Corlan
       (Tycho2 searching, porting of GSC searching code); Liam Girdwood  (various  routines  from
       the  libnova  library);  Pertti Paakkonen (GUI improvements). The star search algorithm is
       similar to (and inspired by) the one in Elwood Downey's XEphem.  WCS  conversion  routines
       are  taked  from  classic  AIPS.  The  GSC  scanning  routines  are  adapted from the code
       distributed with the catalog.

                                        November 27, 2005                                  GCX(1)