### Summary of a FITS file

This window lists information about all the HDUs (Header Data Units) in the opened FITS file. It includes:

1. Index : Extension number (0 is Primary Image)
2. Extension: Name of the extension.
3. Type : Type of the extension.
   - Binary -- Binary table extension.
   - ASCII -- ASCII table extension.
   - Image -- Primary array or Image extension.
4. Dimension: Size of each extension.
5. View :
   - Header -- Display/Edit header.
   - Hist -- Displays a histogram image of 1 or 2 columns in a table
   - Image/Plot -- Display image or plot table column values. The default image display device (POW or ds9) may be selected under the Edit->Preferences->Graphs menu item.
   - Table -- Display a table. (If the extension is an image, then numerical values of the image are displayed as a table).

     All - displays all the columns in a table Select - allows the user to select which columns to display.

   By clicking each button, users are allowed to display and edit the FITS file.

#### Menus

Several menu items operate on "selected" HDUs. One selects HDU's by clicking on the checkbutton next to the HDUs' index.

- File
  - New File...: Create a new FITS file.
  - Open File...: Open another FITS file. See File Selection for details.
  - Save: Save any changes to the original file.
  - Save As...: Save file (with modifications) to a new file.
  - Export HDUs...: Save the selected HDUs into a new file.
  - Make HDU Listing...: Save Extension Name, Type and Dimension in an ASCII file.
  - Revert: Throw away any unsaved modifications and reopen the last-saved version of the file.
  - Close: Close the current Summary window and the opened file. If file has been modified, you will be given the opportunity to save the file before closing.
  - Quit: Quit fv. If any open file has been modified, you will be given the opportunity to save it before exitting.
- Edit
  - Undo: Not support in summary windows.
  - Cut HDUs: Delete the selected HDUs. The deleted HDUs go to the clipboard.
  - Copy HDUs: Copy the selected HDUs to the clipboard. Only one item (could be a list of HDUs though, as long as multiple HDUs are cut/copied at once from a file) is kept in the clipboard.
  - Paste HDUs: All the HDUs in the clipboard are appended to the current file.
  - Clear: Not supported in summary windows.
  - Clipboard: Show the contents of the clipboard.
  - New Extension: A new empty extension will be appended to the current file. You can select whether to append an image, ascii table, or binary table.
  - Preferences: Bring up a window from which fv's behavior and appearance can be modified. See the Preferences help file for details.
- Tools
  - Plot : Plot all the selected valid HDUs(images and tables).
  - Smooth Images: Smooth all the selected image HDUs. The two parameters, width and the height of the smoothing box, will be entered by users.
  - SkyView: Retrieve images of sky at all wavelengths (from Radio to Gamma-Ray) from the NASA SkyView server.
  - Catalog: Retrieve a list of objects in a region of sky from selected catalogs at the NASA SkyView server.
  - VizieR: Retrieve a list of objects in a region of sky from selected catalogs at the Strasbourg VizieR web site.
  - Run Ftool: Run a Ftool program if the HEASOFT or FTOOL packages are installed.
  - Help: A listing of all available help files.

  Go to About fv.