bgsub
-----

What it does:  Provides a quick, interactive way to perform column-based
               background subtraction as well as row-based ramping on
               FITS files.        

Controls:      Dragging the mouse with the left button in the main window
               defines a 'normal' region which the program uses to establish
               background levels to be subtracted.  Every column is treated
               separately, with the averages in that column within the normal
               region being considered the background level for that particular
               column.  The graph below the main window shows intensities
               within the 'normal' region.  For a similar graph of vertical
               intensities, drag the right mouse button to define a second, 
               vertically-oriented region, and a graph will appear to the
               left of the window displaying this information.  Vertical
               ramping is performed by entering numbers into the text fields
               at the bottom right and pressing enter.  The 'next' and
               'previous' buttons go forward or backwards through the FITS
               files in the selected directory.  'save' saves the modified
               FITS image into the 'corrected' directory inside the 'bgsub'
               directory, and advances to the next frame if there is one.

Notes:         None.

        
