Masking out pixels one by one is tedious, how do I mask out a region more easily ?
• Download ds9poly.c: First, download my ds9poly.c program. I will explain how to use this below. But, first compile it by doing: cc -o ds9poly ds9poly.c Download fillpoly.f: Next, download my fillpoly.f program. I will explain how to use this below. But, first compile it by doing: f77 -o fillpoly fillpoly.f Download SAOimage DS9: Now download SAOimage DS9. This will let you draw polygons over the region you want to mask out without having to guess. Drawing a polygon into DS9: Click on the “Region” button, then the “Poly” button. Create a polygon by click-dragging (don’t just click — you’ll have to drag too) a square box in the image. You start out with a square, but you can add vertices by clicking and dragging on the green border. You can also delete vertices by putting your cursor carefully on a vertex and hitting the “Backspace”key (if you delete the polygon by accident, go to the “Edit” menu and hit “undo”). Saving the polygon: Once you have a polygon to your liking, output