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    Re: apparent size of sun and moon
    From: Frank Reed
    Date: 2013 Mar 6, 06:40 -0800

    Joel, this particular image and its odd "North Pole" back-story have been making the rounds for nearly eight years. It's been posted to NavList before at least twice -- in March 2006 and again in January 2009.

    Here's a copy of some of my comments from 2009:
    "It's not a photo, or even a composite of multiple photos. It's pure digital
    art; a fantasy scene as you might find in a video game (ten points if you
    shoot down the Moon before the Giant Squid eats you!). This particular bit of
    digital art was created by a kid in Germany using software called "Terragen"
    which, IMHO, is the real 'work of art' in this story. Here's their web site:
    http://www.planetside.co.uk/terragen/. The image was picked up by the
    forward-hordes sometime back in 2005, re-labeled, and given the usual
    "forward to all your friends" chain letter treatment.

    So how can we tell it's not real? I've got three clues...

    1) The Sun is too small compared to the Moon. That's a big clue. But the image
    might be mis-labeled, so maybe we should set that aside for the moment and
    consider the possibility that it's actually an over-exposed image of a star
    or planet.

    2) If it's taken from any place on Earth, the only objects that can appear as
    crescents are the Moon and Venus. I can't think of anyway to get the water
    foreground in the same image if it's Venus, so we have to assume it's the
    Moon. We now have a scale. Figuring about 16' for the semi-diameter of the
    Moon, the altitude of the Lower Limb is about the same, 16 minutes of arc. At
    that altitude, it is physically impossible for the Moon to have a perfectly
    circular outline. It should be flattened by refraction. Yet it's perfectly
    circular. This is the killer.

    3) Finally, there are no craters. At this scale, you will always find craters
    and isolated mountain peaks visible near the Moon's terminator.

    In late spring 2006, the various "urban legend" sites wrote this up, too.
    Try here: http://www.snopes.com/photos/natural/northpole.asp
    And here: http://www.hoax-slayer.com/north-pole-moon.html
    And also NASA's APOD site here:
    http://antwrp.gsfc.nasa.gov/apod/ap060620.html
    "

    I also proposed a challenge:
    "Not even a composite. It's a pure digital fantasy. But here's an interesting
    challenge: the next time the crescent moon is very close to a bright planet,
    I propose attempting a real photo that duplicates as nearly as possible the
    appearance of this digital image. Then we start a new email forwarding game
    and see how many people happily assure us that, "as everybody knows," it's
    not a real photo. For starters, what's the range of latitude where the horns
    of the crescent moon can be exactly horizontal?"

    If you would like to read the earlier NavList posts on this image, the "custom search" function makes this easier. From 2006:
    http://www.fer3.com/arc/sort2.aspx?y=200601&y2=200604&subject=moonrise
    and from 2009:
    http://www.fer3.com/arc/sort2.aspx?y=200901&y2=200903&subject=crescent

    Another problem with this "image" even as a fantasy. On any planet with a thin crescent moon in the sky, the "dark" part of the Moon should be illuminated by "earthshine" (fantasy-planet-shine??).

    By the way, as for possible geographic locations, we can easily determine that this is not the North Pole. There are no candy canes and no reindeer. If an astronomical solution is required, note that the horns of the crescent moon can never be horizontal at any arctic (or antarctic) latitude under any circumstances.

    -FER
    PS: In my comments above, I said that the image was created by a "kid" in Germany. That was at least eight years ago. I suspect this image and its story will bounce around as "forward-fodder" long enough that I will have to re-write this and say that it was created "by a middle-aged man in Germany when he was a teenager".
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