-go to menu-edit-define pattern. call it sun and press ok. 
-now open a new document 20cmx20cm. -double click on the background layer and select ok. -again double click on the background layer to open the blending options and select pattern overlay. -choose the sun pattern (probable the last one) and scale it to 17%. 
-make a new layer and put him under the background layer. press ctrl+e to merge the layers in to one layer. -go to filter-destort-polarcoordinates. Make sure that rectangular to polar is selected an press ok. 
-If you want to change the color just go to select-select color and select black or white. put fuzziness on 200% 
and press ok -now press ctrl+x to delete the selected area. 
-double click on the layer and choose color overlay to change the color.
