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    Re: Mathematical prediction of "Manhattanhedge" ??
    From: Frank Reed
    Date: 2022 Jul 11, 09:25 -0700

    Joe W, you asked:
    "Is there any place or online domain where I can watch that specific show?Alway more intrigued to see an experienced navigator presenting his expertise from an vivid TV show than just plain text on a forum."

    You can find a link to it at ReedNavigation.com/vid/. You'll need a password (see PS). But I should forewarn: while it was fun being "on tv", there's very little actual celestial navigation in it. The primary interview was with Nainoa Thompson, the Polynesian navigation expert who has been sailing Hōkūleʻa, a Hawaiian reproduction of a traditional ocean-sailing waka or wa'a (a large catamaran), since the late 1970s. My job was to provide "color commentary" to accompany the primary interview and, among other things, that meant pop culture references to movies (e.g. the stars at the end of the original theatrical release of "Titanic" 25 years ago were not merely wrong, but trivially mirrored on-screen, so horribly wrong). I also talked about the basic principle of the sextant and "teased" Dava Sobel a bit regarding lunars. We filmed from just before midnight to 3:00am and only about 45 minutes made it into the show, so clearly it was the editors who crafted the emphasis of the content ...not me!

    You also asked:
    "Also very interested in the sextant that you were holding? Could you tell me a bit more about this rare breed? Never seen a sextant with such a 'lattice-like' frame. Definitely a vintage one, but as I typed 'vintage sextant' on google I came up with none that resembles this one."

    I don't know much about it. I estimate that the instrument was manufactured around 1850. It's Tyson's own. The production team had it out on the table for me to talk about in basic terms during the show. As I mentioned to him in the episode, I would call it a quintant since it has a large angular range. It's certainly an interesting instrument, but it was in rather poor condition, unusable for navigation and not much even as a collectible. Looks good on a shelf in his office though! You can browse some historical "quintants" in the collection of Royal Museums Greenwich here: https://www.rmg.co.uk/collections/objects/search/quintant. By the way, the term quintant is pedantic and un-necessary. Any device capable of measuring angles across the sky can safely be called a "sextant" whatever its angular range may be, but sometimes it's fun to pull out the stops on the old terminology just for linguistic variety. Gets people thinking! :)

    Frank Reed
    Clockwork Mapping / ReedNavigation.com
    Conanicut Island USA

    PS: The password for the video linked above consists of the first four positive-integer solutions to the equation y = x. In other words, the password is 1234.

       
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