You can find this filter through
→ →This filter creates a big star reminding a super-nova. It works with RGB and GRAY images. Light effect decreases according to 1/r where r is the distance from star center.
Parameter setting results are interactively displayed in preview. Scroll bars allow you to move around the image.
You can use input boxes to set horizontal (X) and vertical (Y) coordinates of SuperNova center. You can also click and drag the SuperNova center in preview.
Show Cursor: This option brings up a reticle in preview, centered on the SuperNova.
Color: When you click on the color dwell, you bring up the usual color selector.
Radius: This is radius of the SuperNova center (1-100). When you increase the value, you increase the number of central white pixels according to r*r (1, 4, 9...).
Spokes: This is number of rays (1-1024). Each pixel in the nova center emit one pixel wide rays. All these rays are more or less superimposed resulting in this glittering effect you get when you move this slider.
Random Hue: Colours rays at random. (0-360) value seems to be a range in HSV color circle.