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Subject: Re: HP 48GX Sight Reduction Programs
From: Aubrey O'Callaghan (ocallaghan@XXX.XXX)
Date: Mon Oct 08 2001 - 08:22:12 EDT
Lee,
I agree with George, that the discussion should be kept on the board.
I have a program for the Psion III called Sightmaster 3. I am basically
want to get all the functionality of this program and a few more things
programmed into the HP49.
I am programming with User RPL - should be compatible with HP48. I believe
it takes up more space than system RPL, but I'm new to "advanced" HP
programming. My previous HP was a HP38 which was relatively simple to
program. I started trying to write the software using a line editor on my
PC but found it was easier to write straight into the HP 49. By the time I
debugged and got things to load I was loosing a lot of time. (By the way, I
have an excellent editor called Ultraedit very good for all sorts of
programming worth downloading to try it www.ultraedit.com)
At present I am working on getting the engine running and not worrying
about interfaces.
I am writing each equation as a separate routine and then calling these
from a main program.
I have successfully programmed in the sun and moon, the moon computations
are within .2' of values given in almanacs of various years - randomly
picked dates. I guess this is sufficiently accurate for our navigational
purposes. The sun is pretty well spot on.
I have completed the progamming of the stars to give me the apparent
position of a star from the proper motion. However I have not yet added
the proper motion for all the "navigational" stars.
Planets are giving me a headache, I have calculated the elements for
planetary orbits but need to get heliocentric coordinates and then to
geocentric coordinates; when you start to read Meeus you'll know what I mean.
Aubrey.
At 19:49 06/10/01, you wrote:
>Hi Aubrey,
>
>It sounds like you are going down the same track as me.
>
>My copy of Meeus is in the post on the high seas. Meanwhile I intend
>trying to get some of the almanacs and sight reduction programs on
><http://www.hpcalc.org>www.hpcalc.<http://www.hpcalc.org>org working...but
>have to build my HP to PC cable first! At first glance, these programs
>don't seem to have a friendly user interface, and its very difficult
>working through somebody elses RPL.
>
>I would certainly be interested in sharing experiences or collaborating to
>reduce work. What programming language are you using? I understand User
>RPL is basically compatible across the 48/49 range, provided care is taken
>not to use the special instructions peculiar to the later machines...ie
>User RPL is upwards compatible, but not downwards if the extended
>instruction set in later machines is used. Does your manual have any
>comments on compatibility??
>
>Perhaps we should take this discussion off List?? Others who may be
>interested can follow.
>
>Lee Martin
><mailto:glendonJLM@XXX.XXX>com
>
>
>----- Original Message -----
>From: <mailto:ocallaghan@XXX.XXX>Aubrey
><mailto:ocallaghan@XXX.XXX>O'Callaghan
>To:
><mailto:NAVIGATION-L@XXX.XXX>COM
>
>Sent: Friday, October 05, 2001 11:41 PM
>Subject: Re: HP 48GX Sight Reduction Programs
>
>Lee,
>I recently bought a HP49G and a copy of Meeus Astronomical Algorithms. I
>have been busy doing some initial programming.
>I have got almanac sorted out for sun positions and moon positions.
>I'm finding it quite a good way to learn my way around the HP programming
>language.
>Progress is quite slow as I have too many other things to do, but I'm
>happy to share my experiences with you.
>Aubrey.
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