title: How to change the color of the circular region from green to red in ds9 through python using pyds9
body: <p>I am using pyds9 to automatically load the fits images (for astronomy-related purposes).  </p>
  
  <p>I am able to configure all the other settings like scale, color and zoom level.
  For each image what I want to do is draw a small circle in a particular location that highlights that region. By default this color is green. How do I change this color?</p>
  
  <p>Also is there a way to change the thickness of this circle? I am having issues with visibility. The green color is not clearly visible for all cmap and scale combination. Something like red would be better.</p>
  
  <p>I looked at the XPAset commands. There is a way to do it. But I can't figure out how to do it in pyds9. Here is the link for all the XPAset commands: <a href="http://ds9.si.edu/ref/xpa.html#regions" rel="nofollow">http://ds9.si.edu/ref/xpa.html#regions</a></p>
  
  <p>The xpaset command is :</p>
  
  <pre><code>*$xpaset -p ds9 regions command '{circle 100 100 20 # color=red}'*
  </code></pre>
  
  <p>How do I translate this xpaset command to pyds9's <code>d.set()</code> method ?? </p>
  
  <p>I mean something like : <code>d.set('regions','fk5; circle(100,100,20") # color=red')</code></p>
  
  <p>Following is the code that I am using:</p>
  
  <pre><code>import ds9
  
  # x is the RA and y is the DEC 
  # for describing the location of astronomical objects
  x = 200.1324
  y = 20.3441
  
  # the four FITS images to be loaded
  image_list = ['img1.fits.gz','img2.fits.gz','img3.fits.gz','img4.fits.gz']
  
  #initializing a ds9 window
  d = ds9.ds9(target='DS9:*', start=True, verify=True)
  
  for i in range(len(image_list)):
      d.set('frame ' + str(i+1))
      d.set('file ' + image_list[i])
      d.set('cmap bb')
      d.set('cmap invert')
      d.set('scale zscale')
      d.set('scale linear')
      d.set('regions','fk5; circle('+str(x)+','+str(y)+',20")')
      # This previous line draws a green circle with center at (x,y) 
      # and radius of 20 arc-sec. But the color is by default green. 
      # I want to change this to lets say red. How do I do it ???
  
  
  # arranging the 4 images in tile format
  d.set('tile') 
  for i in range(len(image_list)):
      d.set('frame ' + str(i+1))
      d.set('zoom to fit')
  
  d.set('saveimage png myimagename.png')
  
  # time to remove all the images from the frames
  # so that the some new set of images could be loaded
  for i in range(len(image_list)):
      d.set('frame delete')
  </code></pre>