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    Re: Additional error found in H.O. 249
    From: Brad Morris
    Date: 2009 Oct 7, 16:25 -0400

    Hi Gary
    What is the magnitude of these errors?  Several arc-seconds? An arc-minute?  
    Several arc-minutes? A degree?!!?!?!?
    My 1853 Bowditch gives a long term almanac, in which the motion or rate for 
    the stars is given for a year, and you just multiply by years and add to the 
    base value.  Surprise, it agrees quite
    readily with current values (not perfectly, but dang close).  It didn't seem 
    like a huge delta for a 156 year run (1853 -> 2009).  I can't imagine this to 
    be a huge injected error for 1982 -> 2009.
    I do understand that stars have proper motion.  Wouldn't one obtain the SHA 
    and declination of a star from the Nautical Almanac for the day in question?  
    Why would it be preferable to obtain
    this from HO 249 other than convenience?
    Best Regards
    -----Original Message-----
    From: navlist@fer3.com [mailto:navlist@fer3.com] On Behalf Of Gary LaPook
    Sent: Wednesday, October 07, 2009 3:59 PM
    To: navlist@fer3.com
    Subject: [NavList 10095] Re: Additional error found in H.O. 249
    Here is the response I received today:
    While the Navigational Stars pages may be somewhat out-of-date, this is
    not really  considered an error. Our policy is that on-line publications
    should contain the same information as their current printed editions.
    The 1982 editions of Volumes 2 and 3 are still the current issues of
    these publications.
    The Navigational Star pages will be updated when the next editions are
    Tim Doherty
    Office of Global Navigation/Technology
    National Geospatial-Intelligence Agency
    glapook@pacbell.net wrote:
    > Tim Doherty
    > Office of Global Navigation/Technology
    > National Geospatial-Intelligence Agency
    > I hate to point an error that still remains in H.O. 249. This one is
    > fairly minor. Each of the on line volumes contain a table of the
    > positions of the navigational stars. Volume 1 has the table for the
    > current positions of the stars, epoch 2010. However, volumes 2 and 3
    > have the table with the positions of the stars in 1985 which is
    > unusable this many years later. You should replace those tables with
    > the correct one from volume 1.
    > Gary LaPook
    > >
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