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The SawTooth Hot Key

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NGC 2261 - Hubble's Variable Nebula
Image of Hubble's Variable Nebula (NGC2261) taken 11 February 1997
The SawTooth Hot Key will help you examine extended images such as galaxies and nebulae by breaking up the brightness distribution into 'stages' which will show brightness contours. The total range between BLACK and WHITE is divided into the number of stages you select after pressing "S" or "s" in the Examine Mode. Each stage is then given the full range of 190 grays (if possible) and each stage will be divided by a sharp White/Black transition which will mark the contours nicely. Remember, there is an interaction between the BLACK and WHITE levels you select for the image display and the number of SawTooth levels.

Compare this photo of Hubble's Variable Nebula (NGC2261) taken 11 February 1997 to the one taken 10 March 1997 shown in the SawTooth Function description.

Upon loading a new image, the SawTooth level is set at one. The SawTooth function only affects the displayed image and not the underlying pixel values (which still can be read in the Examine mode with the cursor controls). See the SawTooth Function to actually modify the underlying data for saving to a file.