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    Re: Faint stars easier to find on the horizon first?
    From: Fred Hebard
    Date: 2004 Jun 1, 08:26 -0400

    You can find HO 249 online somewhere or another, to peruse it, perhaps
    at the Naval Observatory site, http://aa.usno.navy.mil/.  As I recall,
    it directly gives the altitude and azimuths of various bodies, without
    need for much interpolation.  So it is very easy to use.
    On Jun 1, 2004, at 6:12 AM, Jim Thompson wrote:
    > Just to clarify for the list -- precomputation was reasonably well
    > covered
    > in our course, and methods are handily available in most computer
    > programs
    > for CN.  But the specific point that has intrigued me is how much
    > easier it
    > is to find a star on the horizon before the naked eye can pick it up
    > in the
    > sky.  That is the trick that was not mentioned or sufficiently
    > emphasized in
    > our course work.
    > I had viewed preplanning as useful for beginners and handy for
    > professionals, but did not realize that it can be essential in order to
    > improve the odds of shooting a good set of twilight bodies when the
    > horizon
    > was optimum, early in evening twilight (or later in morning twilight).
    > As an aside, I spent a lot of time learning to use the 2102-D Star
    > Finder,
    > but even after working out its mysteries I still find it considerably
    > more
    > fussy than tapping up the predictions on a handheld or laptop
    > computer.  And
    > I have not yet learned to use 249.  The best software that I've found
    > for
    > precomputing a full set of bodies for a given time is the old DOS
    > program
    > NAVPLANNER by list member Stanley L. Klein: it generates great lists of
    > bodies sorted by magnitude, highlighted by alitude window.  It also
    > provides
    > sunrise/sunset data for the date/DR position:
    > http://jimthompson.net/boating/CelestialNav/NavsetPC.zip
    > Hopefully Stanley can find time to do up a Windows version (wink,
    > wink).
    > Jim Thompson
    > jim2@jimthompson.net
    > www.jimthompson.net
    > Outgoing mail scanned by Norton Antivirus
    > -----------------------------------------
    >> -----Original Message-----
    >> From: Henry C. Halboth
    >> You bring up a very good point - pre-computation of altitude and
    >> azimuth
    >> seems to be a neglected wrinkle in practical navigation and is barely
    >> mentioned in most navigational texts to which I have quickly
    >> referred...

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