Loading the Image

The Multi-Extension FITS (MEF) file

The image of the field should be a reduced (co-added) GMOS image supplied by Gemini, or a similarly reduced image. The image should be a MEF file. More information about MEF files can be found on the data formats page.

Loading the MEF

1. Use the "File - Open" command in the menu. From the pop-up window chose the FITS file (e.g. mask.fits) and click "OK".
   
   
2. Since the image is a MEF, you will on Sun/Solaris machines be required to chose which extension you wish to open (see window below). Click on the second header unit (HDU) and then click "Open".
   
   
3. Once the image is loaded (it may take a few seconds), the image window should look similar to below.

A few points to note:

• To adjust the color scale of the image, go to "View - Cut levels" on the main menu. This will open a window in which it is possible to adjust the intensity levels of the pixels. For instance, if the intensity level is too low, then to increase the level change the "Auto set" from 100% to 98%. This changes the fraction of pixels that are within the cut levels. Then "Close" the pop-up window when all required changes are made. Also, one could use the "low" and "high" rectangle at the bottom of the right panel (above the "Auto Set Cut Levels" button).
• To zoom-in on the image, to view objects in more detail, click on the large "Z" button to the bottom-left of the screen (see above). Similarly, to zoom out of the image, click on the small "z" button.

Back to GMOS Mask Making Software Instructions

Last update April 30, 2004; Inger Jørgensen
In original form February 10, 2003; Dione Scheltus