Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Re: Calculators for Navigation
    From: Dan Allen
    Date: 1999 Mar 16, 12:28 EST

    You can easily program in the sight reduction formula into an HP19BII or any
    other HP calculator with HP Solve.  This is, of course, just the law of
    Spherical Trig Law of Cosines
    cos(a)*cos(b) + sin(a)*sin(b)*cos(ab) = cos(c)
    and then you can use it to solve both great circle distance calculations and
    sight reduction by the following use of a, b, ab, and c:
    For Great Circle Distance Computations:
    a = 90 - lat1, b = 90 - lat2, ab = lon2 - lon1: c*60 = distance in nmi
    b = c, c = b, recalc and ab = inital course
    For Celestial Nav Sight Reduction:
    a = 90 - estLat, b = 90 - decl, ab = LHA = GHA - estLong, 90-c = altitude
    b = c, c = b, recalc, and ab = azimuth (360-az if lha < 180)
    -----Original Message-----
    From: Titanium Tom [mailto:titom@XXX.XXX]
    Sent: Friday, March 12, 1999 7:29 PM
    To: Daniel K. Allen (Visual C++); Daniel K. Allen (Visual C++)
    Cc: 'Mike Wescott'; Dan Hogan; navigation@XXX.XXX
    Subject: Re: [Nml] Calculators for Navigation
    My calculator that I  presently use is an HP19BII,  Buisness  Consultant II
    which has RPN also.  Do you think that I will be able to use it for what I
    need for our purposes here on Silicon Sea II ?
    Thanks for the help.
    T Tom.
    Daniel K. Allen (Visual C++) wrote:
    > Personally I prefer to spend my time doing lots of programming on my
    > to get sight reduction to the fewest keystrokes!  The HP 48 uses very
    > power and has great built-in functionality.  It has a strange programming
    > language called RPL (Reverse Polish Lisp) but it is quite powerful.  Sadly
    > HP is doing very little with calculators any more.
    > My best nav programs are written in the C programming language and run on
    > laptops, although I am about to port them to a small HP620LX Windows CE
    > machine... which is what HP is putting its efforts to now.  At least these
    > machines can be programmed in C -- a big step forward -- but they do not
    > support much programming on the machine: you need to write the programs on
    > desktop machine running Windows 98 or NT.
    > I've begun experimenting with some nav software written as an Excel
    > spreadsheet, and it actually works quite well.  These Handheld PCs that
    > Windows CE (like the HP620LX and their newer Jornada) have a Pocket Excel
    > ROM and one CAN program on the handheld machine in Excel simply by writing
    > formulas.  (No macros or VBA yet though.)
    > One of the great advantages of using Excel for numerical calculations is
    > that you can see as much of your intermediate results as you want along
    > way.  You can change just one variable and see how it affects the answer,
    > etc.  Writing nav software using Excel is actually pretty promising!
    > Dan
    > danallen@XXX.XXX
    > -----Original Message-----
    > From: Mike Wescott [mailto:mike.wescott@XXX.XXX]
    > Sent: Friday, March 12, 1999 6:18 AM
    > To: Titanium Tom
    > Cc: Dan Hogan; navigation@XXX.XXX
    > Subject: Re: [Nml] Silicon Sea II: Show of Hands
    > > What type of calculator is the best for working the calculations, should
    > it be
    > > programable?
    > Personally, I prefer minimal computer help for doing the Silicon Sea
    > problems
    > (and maximal help on the open sea). I use a simple calculator and plotting
    > sheets. If I weren't too lazy to use an Ageton method (or one of it's
    > relatives,
    > I would do without the calculator.
    > --
    >         -Mike Wescott
    >          mike.wescott@XXX.XXX
    =-=  TO UNSUBSCRIBE, send this message to majordomo@XXX.XXX:     =-=
    =-=      unsubscribe navigation                                         =-=

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site