Before you start make sure you set your Fill color to None and Stroke color to Black or whatever color you prefer.
Step 1 Your draw a circle. The one I drew was 100 px in diameter.
Step 2 Select Window>Stoke (Ctr+F10) to bring up the Stroke Panel and click on the Show options to view all the Stroke options.
Step 3 Now increase the Stroke Weight until you get something similar to a circle. For a diameter of 100 pixels a weight of 100 pixels should do it.
Step 4 Now Click of the Dashed Line option and… tadam!!! You have your Vector Sun Rays. But what if you want to spice things up?
Step 5 You play with the Dash/Gap Values!
Let's try a 3-4-1 setting
Now a 5-3-2-1-12 setting
Make sure that before you use your customs sun rays you expand your circle by using Object>Expand from the menu bar.
As you seen you can get some real funky, retro vector sun rays for your backgrounds in less than a minute. Your Vector Sun Rays are ready to be used in your backgrounds. You can easily add a Radial Gradient in Illustrator to add a bit of dept. You now have a cool background for your next illustration.
More Vector Graphics: 
