Can your Sony change the shutter speed?

If so, leave the shutter open longer, and turn down the ISO settings so there will be less digital noise.

You will need a tri-pod, as the camera needs to be absolutely still while the shutter is open.

A lot of point and shoot cameras attempt to keep things simple, by boosting the cameras ISO (its sensitivity to light) to a high level so it can keep the shutter speed fairly quick. If you can make the shutter speed slower, and turn down the ISO, the camera will 'soak up' more light..essentially getting the same result with much less static-like digital noise.

It will make your black back drop much more rich and pure.

Your composition looks great though!!