On a cold day in late November 1853, in a place called Big Timbers, in what is today southeastern Colorado, a Jewish photographer named Solomon Nunes Carvalho hoisted his ten-pound daguerreotype camera onto a tripod and aimed his lens at a pair of Cheyenne Indians. At first glance, the resulting image, scratched and faded from years of neglect, seems unremarkable. But in fact it is probably the oldest existing photograph of Native Americans taken on location in the western United …