How do I create a passband image?

The DATACUBE package offers two ways to create passband images: first we may use (as before) the squash shell script, this time specify more restrictive $\lambda$ limits, e.g.

   % squash -i ifu_file -o out -l 5490 -u 5690 -p

would create a two-dimensional passband image, collapsing a 200 Å-wide section of the spectral axis.

Figure: The passband script.

Alternatively, we may choose to generate our passband image interactively using the passband shell script.

   %passband
   NDF input file: ifu_file

         Input NDF:
           File: ifu_file.sdf
         Shape:
           No. of dimensions: 3
           Dimension size(s): 59 x 110 x 961
           Pixel bounds     : 1:59, 1:110, 1:961
           Total pixels     : 6236890
         Collapsing:
           White-light image: 59 x 110

     Left click to extract spectrum.

         Extracting:
           (X,Y) pixel             : 32,71
         NDF array analysed        : DATA

            Pixel sum              : 47734.279694
            Pixel mean             : 49.671466903226
            Standard deviation     : 62.703311643991
            Minimum pixel value    : -21.781915
               At pixel            : (31)
               Co-ordinate         : (4697.297)
            Maximum pixel value    : 916.4472266
               At pixel            : (174)
               Co-ordinate         : (5526.027)
            Total number of pixels : 961
            Number of pixels used  : 961 (100.0%)


   Zoom in (yes/no): yes

     Left click on lower zoom boundary.
     Left click on upper zoom boundary.

         Zooming:
           Lower Boundary: 5237.92
           Upper Boundary: 5756.03

     Left click on lower boundary.
     Left click on upper boundary.

         Passband:
           Lower Boundary: 5498.83
           Upper Boundary: 5561.82
         Collapsing:
           White-light image: 59 x 110
           Wavelength range: 5498.83--5561.82 Angstrom
         Plotting:
           Left: White-light image.
           Right: Passband image (5498.83--5561.82 Angstrom)
   %

Here the script presents us with a white-light image and prompts us to click on it to select a good signal-to-noise spectrum, it then asks us whether or not we want to zoom in on a certain part of the spectrum. Let us zoom, and then the script allows us to interactively select a region to extract to create a passband image. It then plots this next to the white-light image for comparison.

Alternatively we can again we can make direct use of the collapse application, upon which both the squash and passband have been built, as shown below.

   % collapse in=ifu_file out=out axis=3 low=5490 high=5560