72 minutes on Cygnus tonight, aimed at the bright star Sadr and the huge field of nebulosity that surrounds it — IC 1318, usually called the Gamma Cygni Nebula after Sadr’s other name, or the Butterfly Nebula for the wing-like lobes that spread out on either side of the star.

It’s a bit of a trick of perspective. Sadr looks like it’s sitting right in the middle of the glow, but the star and the nebula aren’t actually related at all — they just happen to line up from Earth’s point of view. Sadr is a relatively nearby supergiant, about 1,800 light-years out. The nebula behind it is roughly three times farther, at somewhere around 4,900 light-years, and Sadr isn’t even bright enough in the right part of the spectrum to be lighting it up. That job belongs to a hot O9-class star buried somewhere deeper in the dust, energetic enough to ionise hydrogen across hundreds of light-years but too obscured to actually see.

What that leaves is one of the largest emission nebula complexes visible from Earth, and one of the faintest — huge in apparent size but low in surface brightness, which is exactly why it rewards longer integration rather than a quick grab. Even at just over an hour, the wings either side of Sadr start to separate out from the surrounding star field, hydrogen-alpha structure threading through in loops and filaments that don’t show up at all to the eye.

Worth coming back to with more integration time at some point — this is very much a first pass. Full details and the 3D distance view are on the gallery card.