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    Re: Nautical Almanac
    From: Paul Hirose
    Date: 2018 Aug 11, 16:40 -0700

    On 2018-08-10 23:30, Sean C wrote:
    > If you want higher precision/accuracy, I recommend the Multi-year 
    Interactive Computer Almanac or  [LINK: 
    http://www.willbell.com/almanacs/almanac_mica.htm] "MICA" by the U.S. Naval 
    Observatory. It's very slightly more expensive and 'only' good for dates 
    between 1800 and 2050, but it provides many more types of data, at higher 
    precision, than AstroNav.
    
    A disadvantage of MICA is that it displays zenith distance, not
    altitude. Also, MICA doesn't apply refraction. The only angle formats
    available are decimal degrees or degrees minutes seconds. Fortunately
    it's no great challenge to mentally convert seconds to tenths of minutes.
    
    In high precision work there's a nomenclature issue with MICA's "J2000"
    coordinates. In fact, as I confirmed with the USNO, the coordinates so
    labeled are really in the ICRS, which is skewed a few hundredths of an
    arc second from the J2000 system. If you're using MICA as a "gauge
    block" in software tests, it may appear that your code has not
    implemented the two systems properly.
    

       
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