My fiance and I go to Big Bend every year, always through Marfa, but never have time to stop (there or at McDonald! - He's observed at McDonald in undergrad, but I've never been there myself). That's cool that you do volunteering there! We keep thinking that there would be a great potential for McDonald/Big Bend combined outreach.

Living in the desert myself now, on clear nights you can see for miles and miles.

The 1883 lights could have been, say, a lantern on a distant buggy or campfires. Or, perhaps, reflections from their own campfire/lantern.

Did you also see the Prada store in Valentine, TX?

Prada Store Marfa
(and subsequent pictures for closer views)

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[Astronomy's] one of those things that makes us more than just well-fed cows. It satisfies a really deep hunger to know, to go someplace, to explore ...a hunger that is as basic to human beings as food and shelter... -Br. Guy Consolmagno, Ph.D.