You can only plot the slits and spectra for a single mask at a time. If you wish to make changes to objects (including priority changes) then you must go back to the catalog window, make the changes and then re-run the slit positioning algorithm, and then re-load the masks. To load and plot the slits for a particular mask:

1. From the main menu of Skycat, select "GMOS-MMS - Convert ODF FITS to catalog - Convert FITS ODF to Cat ODF (and load) ..."
2. Chose which mask file you wish to open e.g. mask_OTODF1.fits and click "OK".
3. This will bring up a window similar in appearance to the catalog window, see below. The window only contains the columns required to make the masks. Only the objects selected for this mask are displayed.
   
   
4. To display the slits and spectra for each object, click on the "Plot Slits" button. Tilted slits are represented as vertical slits - their tilts are not visualized on the image. The lines shown on the image represent important features of the mask as follows:
   • the red line outlines the field of view
   • the white box show the edge of the spectrum
   • the vertical yellow line shows the position of the slit with the horizontal yellow line going to the center of the spectrum, the edge of which is represented by the double vertical white line
5. To clear the outline of the slits, click on the "Clear Slits" button.

The other buttons function as follows:

• The "Plot GMOS Gaps" button will mark on the image the position of the gaps between the CCDs. To clear the lines representing the gaps from the image click on "Clear GMOS Gaps".
• The "Plot Bands" button will mark on the image the position of the bands if the mask is a Nod & Shuffle mask. To clear the bands from the image, click on "Clear Bands".

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