Effects of Increasing Exposure Time
on NGC 7048

NGC 7048 23 minutes (46 x 30s)
NGC 7048, 23 minutes

NGC 7048 48 minutes (96 x 30s)
NGC 7048, 48 minutes

NGC 7048 76 minutes (152 x 30s)
NGC 7048, 76 minutes

NGC 7048 152½ minutes (253 x 30s)
NGC 7048, 126.5 minutes

As you can see, the background drops away with increasing exposure. In the last image (253x30s) the image brightness was able to be increased without revealing the background.