I am a complete beginner in astronomy. While learning DS9, I came up with the following question.
Say I want to exclude a boxed region from an image FITS. The corresponding parameters according to Chandra is
- Box = (xcenter,ycenter,width,height)
- Box = (xcenter,ycenter,width,height,angle)
Although the name is self-explanatory yet I am confused about their respective units. What unit is used to label these parameters?