This filter is found in
Filters->Light Effectsender->Super Nova
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.
“Supernova” filter options
Parameter setting results are interactively displayed in preview.
Scroll bars allow you to move around the image.
Center of SuperNova
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
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 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.