Animated Star Galaxy Effect

Start by creating a six points star shape using polygon shape tool.

From "Filter" menu select "Distort>>Twirl". Apply settings as shown.

Double click the layer to open layer style window. Apply settings as shown.

Create a new layer and select brush as shown.

Press F5 to open brush settings. Apply settings as shown.

Apply the brush randomly as shown. Move this layer below all the layers in layer order in layer palette. Duplicate the layer. Press Ctrl+T. Right click and select Flip Vertical. Hide this layer.

Create a new layer. Select brush tool with feathered settings. Select violet as foreground color and apply brush strokes randomly as shown.

Select the star layer and change the layer mode to "color dodge".

Duplicate the layer. Press Ctrl+T and rotate it 15°.

Create two more duplicates of this layer and rotate each layer further by 15°.

Select all the twirl layers. Press Ctrl+T. Right Click and select distort. Adjust the nodes to get the shape as shown.

Open animation window. For the first frame hide three duplicates off twirl layer. Also hide one of the stars layers.

Duplicate frame. Hide the first twirl layer and unhide the second duplicate. Also hide the first stars layer and unhide the flipped one. Similarly duplicate frames and repeat the above steps to reveal the rest of the duplicates of twirl layer with stars layer hide/unhide every alternate frame.

Press Ctrl+Alt+Shift+S to save an optimized animated GIF.