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    Star ID method
    From: Paul Hirose
    Date: 1998 Jun 23, 00:45 -0400

    I used Pub. 229 to identify the mystery star from Silicon Sea Leg 42.
    
    Latitude is 37, so we know the volume and column to search.  The
    problem says the star is a little to starboard of dead ahead, our
    course is 98 true, so I guessed 100 for the azimuth.  Azimuth angle,
    Z, is therefore 80.  Altitude was observed at 30 deg.  So we're
    looking for an entry where Hc = 30 and Z = 80.
    
    Open the book to a random page, look at the left page (dec same name
    as lat), go down the lat 37 column, locate the Hc 30.  Unless we're
    lucky, Z won't be 80.  So we try another page.  Instead of scrambling
    around hapazardly, get systematic.  Turn one page, find Hc 30 again.
    If Z is closer to 80, you're going the right way.  Eventually you'll
    find lat 37, alt 30, Z 80 all come together for LHA 70/290, dec 25
    same name.  LHA 70 would put the star to the west.  It's east, so the
    correct LHA is 290.  Convert LHA to SHA.  Nunki fits pretty well.
    
    That's how I found the star, but in retrospect it could have been done
    better.  The problem with searching for a known Hc, then checking if Z
    is correct, is that the same Hc can occur twice on the same page.
    E.g., on the LHA 70/290 "same name" page, lat 37 column, see how Hc 38
    occurs twice, once at dec 45, again at dec 87.  So you'd have to check
    Z at both places.
    
    It's more efficient to find the closest Z, then see if Hc is correct.
    In any column, Z decreases continuously as you go down the page.  You
    won't have to worry about your Z appearing twice in the same column.
    
    If you can't find your Hc and Z on the left-hand pages, then of course
    it must be on the right.
    
    Star identification by Hc and Z loses accuracy as altitude increases
    because it's hard to measure or estimate a decent Z when the body is
    way up there.
    
    Remember, just because only one of the 57 navigational stars is close
    to the expected SHA & dec, you haven't got a positive ID.  Many of
    these stars have neighbors of near-identical magnitude.  Take Nunki.
    It's part of the handle of the Sagittarius "teapot".  The other 3
    stars of the handle are almost as bright.  If you're looking through a
    hole in the clouds without being able to see the star field, you could
    easily shoot one of the neighbors by mistake.
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