Making a Sun

Start a new document about 800x800. We will intially make it large, then scale it down. It looks better that way.

- Create a new layer.

- Then use the eliptical marquee tool, and while holding down shift, create a circle selection. Make the selection almost as big as your canvas.

- Fill the selection with black.

- Now go to Filter->Render->Difference Clouds

- Press Ctrl+F two more times to reapply the filter.

Then go to Image->Adjustments->Levels.

Move the center and right slider towards the left, something similar to mine below:

Now go to Filter->Sharpen->Unsharp Mask

Amount: 500%
Radius: 3.0
Threshold: 15

Now go to Filter->Distort->Spherize:

Amount: 100%

Then Filter->Distort->Spherize again, but this time:

Amount: 50%

Then go to Image->Adjustments->Color Balance

Apply the following color levels:

Shadows: +100 | 0 | -100
Midtones: +100 | 0 | -100
Highlights: +70 | 0 | -15

Alternatively, you can use the Hue & Saturation to colorize your sun.

Now sharpen the image again. Filter->Sharpen->Unsharp Mask.

Amount: 300%
Radius: 3
Threshold: 15

Ctrl+D to deselect

If you want to learn how to create stars, see the simple stars tutorial

I add some drop shadow and inner shadow.

Download final .psd file