The 
button and the 
button are both opening a window that allows you to parameterize many different things in the display and the algorithms of StarDust. The set of parameters that are accessible through these two buttons is more or less equivalent. The main difference between the button and the button is that the later is applying your modifications “in real-time”: i.e. You don’t have to click the 
button to see the result of your modifications: you can directly see “in real-time” all the windows of StarDust updating. Thus, the button uses more CPU resources. If you are manipulating extremely large amount of data, you should rather use the button, to minimise the stress on your CPU.