NavList:

Don Seltzer, you wrote:
"The version that I originally received from Navlist was very dark."

Ahh, right... "received" ...meaning that you're viewing these messages in email. The image you see in email is the "thumbnail preview". If you click on it, that takes you to the full-scale image. The full image is not brighter, but because it is higher resolution, the stars are prominently visible. The magnitude limit in the image is about 6.4 (faint!) so you should be able to see a bunch of stars inside the bowl of the Big Dipper. Can you see those? Take a look at my original post on the NavList message boards here [and be sure to "click to enlarge" :) ]. Even at full-scale, you may need to "pinch to zoom" on the image to enlarge further and see some of those faint stars.

And you wrote:
"So what is that bright light on the horizon?  There do not seem to be any lighthouses or other man-made structures on that part of Papa Stour that could account for it."

I'm glad you asked. I've been ignoring that light way out on the horizon assuming it was a vessel out there that just happened to beam a light toward the photographer during the exposure. But looking very closely there's a grey band of land out there, and, checking the map, sure enough a very lonely lighthouse! It appears to be "Eshaness Lighthouse". Assuming that's right, it gives us a proper azimuth reference. I estimate its azimuth is just about 10° true from the spot by the standing stones. And that means that the star θ UMa was actually some degrees off the meridian. How much would that impact the latitude? I haven't worked it out... Anyone?? I expect it's still within reasonable error bounds on this whole thing, but probably worth doing the math (or simulating it in an app).

Frank Reed