NavList:

Antoine C., you wrote:
"about 3 hours after Sun set, in Azimuth close to 080° with Jupiter just above the horizon and Castor and Pollux above Jove: all 3 have a relative appearance extremely close from the one on the picture."

Oh, wow! That's a fascinating coincidence, I would say. But even in a digital image like this, where the depth of star brightnesses seems to collapse, and they often all look the same... if it were Jupiter it would be significantly more prominent. Your comment, though, does bring up another important point, which I probably should have mentioned in the setup for the puzzle, namely angular scale. We're so used to seeing wide views of the sky, covering a couple of large constellations, extending over 60° or more, that it's hard for us to spot regions that are smaller. In this case, my "star pattern" sixth sense kicked in right away when I spotted the little triangle that forms the top of the constellation Lyra. I should have mentioned the scale here is "narrow", as if the "photographer" was maybe 8 or 10 meters away from the "observer" in the foreground. The distance from the "double double" which David Pike correctly identified as "epsilon Lyrae" is about 2°.

There's another issue that should have occurred to me when I provided that clue to look for the "double double". This may be an anglocentric clue, and if so I apologize for that. Much of amateur astronomy, thanks to its 19th/20th century history is distinctly anglophone. Of course that's true also of celestial navigation, but I'm more aware of those cases than the examples that are pulled from broader astronomical sources.

Frank Reed

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