Creating a Galaxy

In order to draw a galaxy lets begin with diamond gradient again, with its corner down (set the cursor in the center of the canvas and while holding Shift drag the stretching upright down).

Now apply to our gradient a filter from Filter > Distort > Glass with the following settings: texture is Thin lens, Distortion 5, softness 3, scale 100%.

Then Filter > Distort > Whirl, angle 260.

Paint our galaxy in the Hue/Saturation dialog from menu Image > Adjust, in the pop-up window set checkmark in Coloration and move sliders in the scales, changing Hue and Saturation.

That was a galaxy, top view. But you can easily obtain a sideview one by transforming the previous picture with Scale and Rotation from menu Edit > Transform.