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    Re: Star-star distances for arc error
    From: Bill B
    Date: 2009 Jun 28, 02:48 -0400

    douglas.denny{at}btopenworld.com
    
    > It mentions specifically measuring star distances for checking sextants.  I do
    > not think you will like the conclusions.
    
    I may not like the conclusion of the article, but I do like the repeatable
    results others and myself and get.( Some theoretical or applied scientists.)
    Also with measuring semidiamter of the Sun as an IE check. Or measurements
    with an artificial horizon.  Or exploring acuity of an eye/sextant/scope
    combination in the field with "touch and leave" observations. I also enjoy
    the findings of hundreds of rigorous to semi-rigorous articles on the topics
    of accuracy/precision with a sextant related to human eyes.
    
    I agree this "discussion" has degraded into a running gun battle in a
    corner, hopping from topic to topic, which seldom solves any question.
    Perhaps, as George likes to do, we create new titles for the various topics
    in an attempt to distinguish between beastiality/sadomasochism and beating a
    dead horse?
    
    For the moment, let's consider optics from a photographic point of view.
    Sure there are formulas to theoretically derive the light transmission of a
    lens. (Contrast is a different animal.) F-stops were originally a tab with a
    hole (aperture) slipped into the lens. After mass-produced film came along
    still photographers had the luxury of testing a lens/film/exposure/developer
    combination and adjusting for the metered contrast ratio and lens
    characteristics etc.
    
    Cine photographers did not have the luxury of developing frame by frame and
    had a lot more $$$ at stake when shooting a production. They had to know the
    transmission characteristics of a lens spot on.  Prior to multicoating etc.
    theory was laid to waste by a 5% loss per lens element and other factors.
    They derived a t-stop ("t" for transmission) that measured what the lens
    actually transmitted--theory be damned.
    
    In the mid 1900's, the quip of the  aeronautical engineers at Purdue
    University was, "Scientists proved the bumblebee cannot fly.  Not knowing
    this they fly anyway."
    
    As I have quoted before on the list, "In theory practice follows theory.  In
    practice it does not."
    
    Another old adage, "Science cannot prove anything, it can only prove what is
    not true." I endorse the scientific method and often reread Richard
    Feynman's "Cargo Cult Science" address.
    
    What the heck, if you have an article stating it cannot work, I'm giving up
    wasting my time and on star-to star distances.  No need to put sand on the
    floor of a rat maze; and I'm going back to altering the shape of the
    coconuts I am using as headphones in hopes of luring a cargo plane full of
    laptop computers to my makeshift landing strip ;-)
    
    To avoid confusion, the above paragraph may have fallen short, but *is*
    meant to be acerbic and/or sardonic wit.  We can debate the nuances between
    "sarcasm" and "sardonic wit" under a different thread name as this goat rope
    already has everything but the kitchen sink thrown in. (Our foreign readers
    may wish to Google "Goat Rope" and "Kitchen sink thrown in")
    
    Bill B.
    
    
    
    
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