fv: FITS Viewer and Editor (version 5.3)

fv is a FITS file viewer and editor developed at the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA / GSFC.

Project Scientist:
Dr. William D. Pence (William.Pence@nasa.gov)
Project Engineer:
Pan Chai (Pan.S.Chai@nasa.gov)

To learn of new releases and bug fixes, visit the fv web page at:

Please send your comments, questions or feedback via the ftools help desk web page at:

Version 5.3 July 2009

New features/Bug fixes since V5.2.1 include:

  • Bug fixed: Fix large FITS file crashing and displaying summary/header issue.
  • Bug fixed: Fix opening FITS files in read-only mode issue.
  • Bug fixed: Fix scale error on colorbar.
  • Bug fixed: Fix axial label and scale issue for image constructed from image table cells.
  • Bug fixed: Fix no plot in pow scope area when displaying/flipping contour map (on separate graph.)
  • Bug fixed: Fix grid displaying issue when flipping a plot.
  • Bug fixed: Fix crashing issue when Zoom and then Reset zoom of images constructed from an image table.
  • Bug fixed: Fix information missing when displaying movie from a 3-D image table.
  • Enhancement: Adding wcsfix routine to handle non-standard WCS keywords values in FITS header.
  • Enhancement: Change release version to 5.3.

Version 5.2.1 July 2008

New features/Bug fixes since V5.2 include:

  • Bug fixed: correct FITS Header string to WCSLib overflow 80 characters limit per card.
  • Enhancement: denote -SIP projection to its counter-part (i.e. -TAN-SIP to -TAN projection.)

Version 5.2 June 2008

New features/Bug fixes since V5.1 include:

  • Bug fixed: file selection panel not been displayed during exiting fv/pow application when the FITS file is modified during the session.
  • Bug fixed: when editing plot/image information, new title string is not been updated in the graph bug.
  • Bug fixed: zoom/unzoom of plot/image cause labels and units of the graph disappeared.
  • Bug fixed: fv/pow crashes during rendering of graph/image if the FITS file consists of inconsistence coordinates or unsupported coordinates system.
  • Bug fixed: un-necessary X and Y labels displayed in POW window (no image/plot created yet) when xspec is invoked.
  • Enhancement: allow the selection of columns panel to remain visible during plotting.
  • Enhancement: allow renaming capability of created region files when running special analysis tools in Hera.

Version 5.1 December 2007

New features/Bug fixes since V5.0 include:

  • Passing Fits Header string and cnt to client to display wcs info correctly for Hera and POWplot operation.
  • Fix zoom in and out bugs on POW image.
  • Support displaying images that straddle the 24h = 00h boundary on the sky with WCSLIB.
  • Horizontal scrolling bug of 0 rows table.
  • Release memory when deleting/closing an image in POW (on-going).
  • Fix editing graph parameter values bug.
  • Fix "Duplicate Graph" casuing seg-fault bug.
  • Fix two identical file names from two directories overwrite each other in POW bug.
  • Fix image flipping bug with FITS keyword CDn_n.
  • Fix displaying linear WCS projection and coordinates image.
  • Add 2 new icons: Hera and Student Hera during installation for Microsoft Windows and Apple Mac OS X.

Version 5.0 September 2007

New features/Bug fixes since V4.4 include:

  • Overhauling POW world coordination calculation logics. Now fV/POW use standard WCSLIB library to generate world coordinates/pixel positions.
  • Allow generating of plots that retains its world coordinate projection information.
  • Allow limited editing capability on the property of graph objects (projection, rotation, etc) of a graph/image on the fly.
  • Allow switching between multiply world coordination system (i.e. WCSa, WCSx, etc.) on the fly.
  • Allow the flipping of image/plot of direction on X or Y or Both axes.
  • Allow display of 64 bits integers in fv data table and in POW imagery.
  • Fix white-wash grey-out POW imagery on Scientific Linux platform bug.
  • Fix saving 64 bits integer data to a text file bug.
  • "Run Ftools..." option is no long available. Users are encouraged to use the new "fgui" task that is distributed with ftools.
  • "Skyview..." catalog selection is now only available via "Catalog..." option.

Version 4.4 July 2006

New features/Bug fixes since V4.3.1 include:

  • Adding capability to re-order the display of FITS columns.
  • Expand capability to sorting/modification of FITS columns parameters.
  • Tracking parent window view via vector columns in "Expand"ed view .
  • Allow user to specify path for DS9 and XPA in Windows.
  • Fix Windows platform of printing countor map on image problem.
  • Modified how the rotation angle in region files is interpreted to be consistent with DS9 (angle is w.r.t. the North direction in the image).

Version 4.3.1 May 2006

New features/Bug fixes since V4.3 include:

  • Expand capability to run fv with more than 9 parameters.

Version 4.3 April 2006

New features/Bug fixes since V4.2 include:

  • Add capability to invoke future HERA modules.
  • Add capablity to calculate Flux on region.
  • Add capability to handle "Physical" attribute in region file.
  • Add capability to center (and resize) of ROI (region of interest) when the image is zoomed.
  • Add capability to allow parameters editor to stay until user decided to cancel.
  • Fix running FTOOLS tools not copying physical par file problem.
  • Fix sorting Fits table but displaying wrong slice image problem.
  • Fix rotation of coordinates results in wrong region specification problem.
  • Fix plotting of selected rows from FITS table problem.
  • Fix ploygon region handle placement and dragging mechanisms problem.

Version 4.2 April 2005

New features/Bug fixes since V4.1.4 include:

  • Add X axis range selection utility in POW.
  • Add capablity to display 4D table and image (movie).
  • Add capablity to create/display region on image.
  • Add XPA entry points for X axis range selection and region display.
  • Fix one dimension plot/image label problem.
  • Update logic for display CAR projection.
  • Rework background backup directory cleanup logics.
  • Fix ploygon creation problem, allow right mouse button to drag the existing vertex, left mouse button for creation and move the region.
  • Add color changes capability in Edit Region Panel.
  • Change vizier/skyview/catalog file naming scheme.

Version 4.1.4 September 2004

New features/Bug fixes since V4.1.3 include:

  • Correct background backup directory cleanup process.
  • Add capability to plot to existing graph in DS9.

Version 4.1.3 July 2004

New features/Bug fixes since V4.1.2 include:

  • Update calculator, calculator expression help files.
  • Add licence.
  • Fix interface to VizieR.
  • Add A4 paper size.
  • Rework print interfac.
  • Fix preview orientation.
  • Fix preview page layout.
  • Add XPA entry points to print/save image on POW.
  • Update profile help files

Version 4.1.2 May 2004

New features since V4.1.1 include:

  • Adding support for Cartesian projection.
  • Adding record capability for profile of FITS image.
  • Enhanced capabilities for printing and saving FITS image or plot, including the ability to preview the image before printing.
  • A row selection function was added to fv. User can select/deselect row(s) by clicking on the row index in the table with the mouse's left button (or clicking left button then right button to select row range). Row(s) also can be selected using selection condition and expression.
  • fv's plot, calculator, histogram and statistics tools now can perform on the selected rows.
  • Export command can export the selected rows and columns from a table to fits file or text file.
  • Delete command will now delete the selected rows and cols.

Version 4.1.1 January 2004

New features since V3.2 include:

  • Enhanced support for ds9 image display
            User can choose to display images or plots using either 
            DS9 or POW as the primary display tool.  
  • Added more XPA points for controlling fv from external processes, including
            create: create an image or table file or extension.
            export: export hdu(s) to a Fits file or a text file.
            opentool: open skyview, catalog, vizier, or ftools dialog panel.
            preference: set up FV preferences.
            See Scripting for more information 
  • Allow user to reverse the functionality of the left and right mouse buttons within the POW display via pow's preferences setting
            default: Left mouse button  - control zoom
                     right mouse button - control brightness/contrast

Version 3.2 October 2002

New features since V3.1 include:

  • New function buttons have been added to the File Summary window to provide short cuts to common operations:
            - 'Hist' - displays a histogram image of 1 or 2 columns in a table 
            - 'Plot' - plots table columns 
            - 'Table All' and 'Table Select'
                     - The first button displays all the columns in a table, whereas the 
                       second button allows the user to select which columns to display.  
  • Vectors or images contained within a single binary table cell may be plotted.
  • When displaying Hierarchical grouping tables, a new 'OPEN' button is available at the beginning of each row which can be used to open the corresponding group member file.
  • Can display and edit images that are compressed with the new FITS 'Tile Compression' algorithm.

Version 3.1 July 2002

New features since v3.0 include:

  • Hundreds of tables available in VizieR can be queried to retrieve objects near a given position
  • Column histogram tool can be limited to a specified row range
  • New tool for editing the name, units and display format of columns
  • 'Export as text' options can print row numbers, and print a user-specified character string between each columns value
  • Double Right-clicking inside a pow graph redraws the graph with the default 1:1 zoom factor
  • If an HDU contains a 1-D image, the 'PLOT' button on the summary window plots the pixel value vs. pixel coordinate instead of displaying a long, thin image
  • The Zoom/in Zoom/out and replot buttons have been moved from the POW canvas and up into the menu bar
  • Integer columns with the TSCAL and TZERO keywords are treated as doubles to prevent data truncation
  • Rows of a vector table, either fixed or variable length, can be plotted

Version 3.0 November 2000

New features since v2.6 include:

  • Search online SkyView database for images or objects located in a given region of the sky
  • Execute an Ftool from within fv (Unix only)
  • Plot vector columns and subsets of rows
  • Smooth image extensions with a boxcar filter
  • Symlinks to files supported
  • Copy/Paste works in all table views
  • More scripting commands
  • New image analysis tools: Ruler (measure distances in an image), Profile (plot a cross-section of an image), Probe (calculate flux and centroid data of image region)
  • New DS9 region files supported

Version 2.6

New features since v2.5 include:

  • Ported to MacOS
  • Improved window management and improved design of some windows
  • Replaced Options menu with a Preferences window which brings together and categorizes all of fv's user-controlled options
  • New Auto-Plot preference
  • Can turn off the Desktop Manager
  • Expanded scripting capabilities via XPA mechanism
  • File Selection window shows file sizes and modification dates
  • POW's information/scope windows can be positioned on any side of the window or turned off altogether
  • New Histogram Equalization color table for images
  • New Text Label handling on graphs
  • Full font control over graph labels

Pages maintained by Bryan Irby
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Last modified: Thursday, 16-Jul-2009 14:09:17 EDT