DS9 capabilities  +
and goals *

Interface 
 * Run in browser
 + Control via python api
 + run locally in Jupyter environment on various TBD platforms
 + run on command line

Functionality
 +   Data:  Images, Cubes, Event files
 +  Regions: creation and interactive manipulation, save/load;  physical and WCS
 +  WCS: full support including nonstandard; WCS at cursor position
 +  Pixel data display:  conttrast, bias, colormaps
 +  Multiple image handling:  frames, RGB, cubes
 +  Overlays:  WCS grids
  +  Output:  Save as jpg, png, [pdf *], printing