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    Re: Lewis and Clark lunars: more 1803 Almanac data
    From: Ken Muldrew
    Date: 2004 Apr 17, 08:25 -0600

    > The rate in the almanac data is geocentric. You would have to
    > calculate the apparent topocentric rate incorporating changing
    > parallax and refraction in order to compare against the observed rate.
    You're right, of course. My thinking was that an estimate of the angle
    formed by the line connecting the moon and Aldebaran, as well as the
    line connecting the moon and the mystery star, even if it was out by 5?,
    taken together with the measured distance, would lead to one, or at
    most, two stars that could possibly be misidentified as Aldebaran (and
    even then, only with partly overcast conditions). This process would
    basically give two regions-of-interest, one North and one South of the
    ecliptic in which to search for candidate stars.
    > And:
    > "It's pretty hard to misidentify either Aldebaran or Rigel."
    > Although I don't think one can reach the conclusion that they
    > misidentified their star *yet*, it is a real possibility. For anyone
    > trained in celestial navigation in the past 75 years identifying the
    > stars is part of the game. But back then it wasn't. Stars were rarely
    > used by navigators in the 19th century *except* the nine lunars stars.
    > Bowditch and other navigation manuals included little charts and
    > descriptions for these stars and no others. Certainly many people
    > learned the constellations for their own amusement, but those who did
    > not would have a tough time picking out the right stars until they
    > accumulated some serious experience.
    This comes as quite a surprise. I would have thought that everyone
    would have at least a passing familiarity with the constellations of the
    zodiac and a few of the more obvious ones (such as Orion, Ursa Major,
    etc.) in the era before streetlights. If what you say is true, then I think it
    increases the likelihood of the hypothesis that another star was
    misidentified as Aldebaran.
    Ken Muldrew.

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