I like the colors you used. Blue is my favorite color! I like how the light source seems to come from the center and move outwards. I also like how there are individual light sources in the image as well. The lighting seems to carry out lines or at least give off the illusion of lines. I like how my eyes are drawn to this movement. I think its cool how you varied the size of the stars. I'm guessing you did this to play with shape, size, or distance. This is a cool technique. I think this piece would look cool as a gif or a stamp. Have you considered, doing this and making the images twinkle? I think it would really add to the piece. It kind of looks like the center star may be going supernova! For a five minute job, this is a neat piece.
Have you thought about framing the piece in a different color to offset the image? Kind of like how the DA stamps have the jagged edges? I think it would look neat. Possibly a black or a white plain border? Or you could go with something even more detailed not too detailed because you don't want it to outshine the image itself. Just a little bit of texture to give the illusion of a frame. I was thinking too you could even do a similar purple within the vain of colors you are using for a softer frame feel as well. Oh, the possibilities!