This is fragment of old photo, slightly postprocessed. I created a mask for stars (using levels on monochrome copy of picture) and added some glow to stars with it.
Shooting stars in city like Moscow, with strong light pollution, really painful task. For this picture, i aligned and averaged stack of 10 long exposure shots (15 seconds each), choosed very clean and starry night, and take source photos on very edge of the city.