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Display and graphic windows

In the early reduction stages it is recommended to create a display with the same number of pixels as the CCD frame, so that one can easily check for defects.

The following example is only useful on workstations:

CREATE/DISPLAY 0 520,337
CREATE/GRAPH
LOAD/LUT heat

The first command will create a display with identification 0 and axes of 520 and 337 pixels. The second command creates a graphic window with the default setting which can be used in most cases. The last command loads a look-up table, i.e. an intensity-to-color conversion table. Other graphic windows, e.g. for the final spectra, can be specified with:

CREATE/GRAPH id x0,y0,xsize,ysize

Then images are displayed by:

LOAD/IMAGE ech0011 cuts=500,2000

which loads the image ech0011 in the active channel, using cuts values 500 and 2000 to define the range of represented intensities. If the image is loaded later, the last settings will be used as default values (they are stored in descriptors LHCUTS and DISPLAY_DATA).

Perhaps the cuts are not adequate and as a consequence desired details do not appear. To measure the intensity of a few pixels, use command:

GET/CURSOR

On a workstation: with the mouse, press leftmost button to get the values, and the center one to exit.

On a DeAnza: switch a cursor on, and use ENTER button to get the values. To exit, set both cursors off and press ENTER. Make sure that RATE and TRACK switches are off.


next up previous contents
Next: On-line help Up: Echelle Reduction Previous: Reading the Data
Petra Nass
1999-06-15