LDN 673 looks to me here like a human figure moving to the left and about to step out of the frame. That brought to mind one of my favourite new wave tracks, Steppin' Out (as in stepping out in NYC at night), by Joe Jackson, and thus my title. 🤓 

Beverly Lynds published her eponymous catalogue of dark nebulae (with 1802 entries!) in 1962, based on a visual inspection of red and blue prints from the National Geographic Society – Palomar Observatory Sky Survey (POSS). The smallest nebulae in her survey have areas of the order of 2 square arc-minutes, while the largest (LDN 621), with a listed area of 45 square degrees, is a segment of the Milky Way's Great Rift in the north-east corner of Serpens (I'll be looking for it the next time I'm under dark summer skies with a pair of wide-field binoculars!). Lynds also gave a ranking of the nebular opacities, ranging from 1 to 6 (least-to-greatest). @Gary Imm  has a nice compilation of LDN highlights, and digitized versions of the POSS (and successor) plates are available here.

Lynds listed #673 with an area of 720 square arc-mins, and an opacity of 6 (its major portion is roughly 40'x20', judging from the roughly one-hundred available Astrobin posts of this region and, just for fun, looking up a one-square degree red POSS plate centred on its coordinates). Since the full nebula is too large for the FOV of my system, I played with crops of wider-field images of the nebula to try to come up with a frame that would be the most interesting. But in the end, I have to give credit to @Greg Nelson, whose top-drawer rendition of LDN 673 motivated me to try this object in the first place, and that also happens to have a similar-sized FOV to mine: I could not improve on the way that Greg framed the nebula, and my frame is only a slight variation on his!  

There is a beautiful essay about this nebula in the blog Anne's Astronomy News (a personal "astronomy picture of the day") that I thoroughly enjoy re-reading (sadly, Anne passed away in 2015, but her family continues to preserve the site as she left it): Anne's essay puts this object in the expansive context of the Great Rift, and features a rendition by @Adam Block.

My image spans about 31' to a side, at a plate scale of 0.62"/pixel, and is the result of just under 19 hours of exposures, split roughly equally between luminance and RGB colour, and taken over the course of six nights in June. In processing the image stack I tried to preserve as much contrast and depth in the dark clouds as possible, while trying to retain the striking contrast with that especially brilliant blue star (which, at 6th magnitude, was more than a little tricky to manage relative to the nebula).