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    Re: H. Hughes and son sextant pat 491
    From: Frank Reed
    Date: 2019 Dec 3, 09:30 -0800

    David Pike, you wrote:
    "Appendix F in the second edition of his book, is accompanied by a page of explanation where he goes into the effects of refraction and how to minimise it.  Moreover, the table itself is entitled ‘For Practice and Sextant Testing’, not ‘For Sextant Calibration’.  It seems to me that a lot would depend upon the length of the line joining the two stars, its tilt, and how high in the sky it is. "

    Oh Holy Fucking Shit (pardon my French). Every time someone picks up a copy of Bauer's Sextant Handbook, the practice of celestial navigation is gutted and thrown back in time to the addled, ritual-driven state that it was in three decades ago. Bauer peddled his personal habits and tastes as proper sextant procedure. Do not trust anything in that book unless you have triple-checked it from other sources (and why bother? Don't trust anything in that book!).

    Need an example? It's right there in that "page of explanation where he goes into the effects of refraction and how to minimise it" which you referenced above. That advice on refraction includes major errors. For example, he repeats a common myth that was prevalent among navigators in the US Navy, especially, in the 80s and 90s (probably earlier, too). He states: "star pairs in the horizontal plane give more accurate results because when altitudes are about the same refraction can be ignored." This is completely false.

    Frank Reed

       
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