Download NICMOSlook An Interactive Spectrum Extraction Program for

CHAPTER 3. USING NICMOSLOOK
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are assumed to have the extension '.ts', IRAF images '.imh', and SDAS les '.hhh'. If the
extension '.Z' or '.gz' is detected in the lename, the les are assumed to be compressed,
and will be automatically uncompressed using the appropriate utility. There are 2 images
buers, one for the direct image, and one for the grism images. Every image is loaded
into one of these buers. Therefore, at most one direct image and one grism image can be
loaded simultaneously.
3.2.2 Displaying the Images
When the program starts, a 512512 separate display window with coordinate display
will appear. The most recently loaded image will be displayed in this image. The input
image will be resized to t this window. The display window can be resized to any desired
shape using standard window resizing techniques of the used window manager. There are
a number of options to manipulate the image display.
Changing Contrast and Colors: The image contrast can be changed through the
switches labeled Display Scale: Linear , Logarithm , Square Root , and Histogram Eq. .
Changing Color Look-up table: The color look-up table and contrast can be changed
by pressing the Contrast/LUT button. This will pop-up the standard IDL xloadct
widget which presents a choice of look-up tables and display options.
Switching Images with Toggle Buttons: Selecting the Spectrum or Direct Image
toggle buttons displays the image loaded in that buer.
Switching Images with Blink: Selecting the Blink button pops up a window that al-
lows the user to select the rate in which the two images currently loaded are switched,
both in the zoom window and the separate image display.
Using the Zoom Window: Clicking any mouse button once while the cursor is within
the image display window causes the portion of the image centered on the cursor to
be displayed in the zoom window. The zoom magnication is set through the slider
bar below the zoom window.
Resetting Images: Clicking the Reset button removes the images from the display
and eectively resets the application to the initial startup state.
3.2.3 Finding Objects and Extracting Spectra
After loading both a grism image and a direct image into the tool, there are 2 main menu
buttons to produce spectra:
Objects
input le.
Creates an object list from direct image or reads coordinate list from