Create and Display an Image

Two commonly-made plots are those showing PI vs. BETA_CORR (also known as ``banana plots'') and XDSP_CORR vs. BETA_CORR.

To create images by using the GUI:

1)

Check the square boxes to the left of the ``BETA_CORR'' and ``PI'' entries.

2)

Click on the ``Image'' button near the bottom of the page. This brings up the evselect GUI (Figure 6.3).

3)

In the ``Image'' tab in the evselect GUI, confirm that the withimageset box is checked.

4)

In the imageset box, change the output image name from image.ds to something descriptive, in this case, pi_bc.fits.

5)

Click on the ``Run'' button on the lower left corner of the evselect GUI.

Different binnings and other selections can be invoked by accessing the ``Image'' tab at the top of the GUI. The default settings are reasonable, however, for a basic image. Similarly, plots can be made comparing BETA_CORR to XDSP_CORR. These two example plots can be seen in Figure 8.1.

To create images from the Command Window, type:

evselect table=rgs1.fits withimageset=yes
$$ imageset=pi_bc.fits xcolumn=BETA_CORR ycolumn=PI
$$ imagebinning=imageSize ximagesize=600 yimagesize=600

where

table - input event table

withimageset - make an image

imageset - name of output image

xcolumn - event column for X axis

ycolumn - event column for Y axis

imagebinning - form of binning, force entire image into a given size or bin by a specified number of pixels

ximagesize - output image pixels in X

yimagesize - output image pixels in Y

Plots comparing BETA_CORR to XDSP_CORR may be made in a similar way. The output files can be viewed with fv; example plot are shown in Figure 8.1.

Figure 8.1: Plots of XDSP_CORR vs. BETA_CORR (left) and PI vs. BETA_CORR (right). The gap is due to the missing CCD7. Similarly, CCD4 is missing in RGS2.