Is there a publication revealing the algorithms so that a programmer can
avoid having to buy almanacs,etc. and instead generate his own tables
and annual almanac ?

Thank you.
--
Courtney Thomas
s/v Mutiny
lying Oriental, NC

"Courtney Thomas" wrote in message
...
Is there a publication revealing the algorithms so that a programmer can
avoid having to buy almanacs,etc. and instead generate his own tables
and annual almanac ?

Thank you.
--
Courtney Thomas
s/v Mutiny
lying Oriental, NC

Jean Meeus "Astronomical Algorithms" 2nd Ed. Willmann-Bell March 2000 is
the bible.

There is a great deal of software ( a lot of it free) available for
celestial nav calculations (sight reduction) and almanac
calculations......available for PC (laptop), PDA and calculator (mostly HP
and TI) platforms. Most of this software is based on Meeus in one form or
another.

Not much point in recreating existing software, unless you have different,
specific requirements. And if you needed to ask about the existence of
Meeus, it would seem you are well down on the learning curve for creating
applications....no offence intended, just that I asked myself the same
question you have asked, some years ago.

If you care to firm up on your requirements (is it simply sight reduction?)
and platform.... I can possibly point you towards appropriate software. If
you wish to write your own, there are many modules/routines to help you get
started, depending on your platform of choice.

Courtney,

There is a way. You need to get two items in order to do this. First is the
book "Fundamental Ephemeris Computations" by Paul J. Heafner, and the second
is the CD "JPL Planetary and Lunar Ephemerides". Both of these are available
from Willmann-Bell Co. ( www.willbell.com). If you are a clever programmer
you can roll your own almanac. Software is available on the i'net as well. A
good search with Google for "Almanac" will keep you busy for a bit.

Meeus' books are also available at WB and make a good starting point.

HTH

Vic

--
__________________________________________________ ______

Victor Fraenckel - The Windman
KC2GUI www.windsway.com

Home of the WindReader Electronic Theodolite
Read the WIND

"Victory at all costs, victory in spite of all terror, victory however long
and hard the road may be; for without victory there is no survival."
- Winston [Leonard Spencer] Churchill (1874 - 1965)

Dost thou not know, my son, with how little wisdom the world is governed?
-Count Oxenstierna (ca 1620) to the young King Gustavus Adolphus

"Courtney Thomas" wrote in message
...
| Is there a publication revealing the algorithms so that a programmer can
| avoid having to buy almanacs,etc. and instead generate his own tables
| and annual almanac ?
|
| Thank you.
| --
| Courtney Thomas
| s/v Mutiny
| lying Oriental, NC
|

The equations for a direct solution to the spherical triangle (sight
reduction) is in the big thick Bowditch book.
I programmed my HP11 calculator to do it years ago and was very pleased with
the results.

Dave Erickson


"Courtney Thomas" wrote in message
...
Is there a publication revealing the algorithms so that a programmer can
avoid having to buy almanacs,etc. and instead generate his own tables
and annual almanac ?

Thank you.
--
Courtney Thomas
s/v Mutiny
lying Oriental, NC

You should look at the US Naval Observatory's "NOVAS" code (C and
Fortran source available), and Jean Meeuse's "Astronomical Algorithms"
book. Those two sources will get you 90% of the way there (take it
from one who's done it!). For the remaining 10%, hope you were paying
attention in your math classes Actually, there's a published
"Explanatory Supplement" to the nautical almanac (jointly published by
the same two hydrographic offices that do the nautical almanac) which
contains a good bit of (quite technical) exposition. I've also found
Charles Cotter's book "History of Nautical Astronomy" quite useful
(out of print, but in many libraries). I may be mangling these titles
a bit, but I'm sure of the authors.


--
Hal Mueller Get MapTap for PalmOS!
Seattle, Washington http://www.mobilegeographics.com/maptap/

Hal, do you have a link to somewhere that has the NOVAS code?

Thanks,
Tom Dacon

"Hal Mueller" wrote in message
...
You should look at the US Naval Observatory's "NOVAS" code (C and
Fortran source available), and Jean Meeuse's "Astronomical Algorithms"
book. Those two sources will get you 90% of the way there (take it
from one who's done it!). For the remaining 10%, hope you were paying
attention in your math classes Actually, there's a published
"Explanatory Supplement" to the nautical almanac (jointly published by
the same two hydrographic offices that do the nautical almanac) which
contains a good bit of (quite technical) exposition. I've also found
Charles Cotter's book "History of Nautical Astronomy" quite useful
(out of print, but in many libraries). I may be mangling these titles
a bit, but I'm sure of the authors.


--
Hal Mueller Get MapTap for PalmOS!
Seattle, Washington http://www.mobilegeographics.com/maptap/

Tom Dacon wrote:
| Hal, do you have a link to somewhere that has the NOVAS code?

Try
http://aa.usno.navy.mil/software/novas/novas_info.html

HTH

Vic

--
__________________________________________________ ______

Victor Fraenckel - The Windman
KC2GUI www.windsway.com

Home of the WindReader Electronic Theodolite
Read the WIND

"Victory at all costs, victory in spite of all terror, victory however long
and hard the road may be; for without victory there is no survival."
- Winston [Leonard Spencer] Churchill (1874 - 1965)

Dost thou not know, my son, with how little wisdom the world is governed?
-Count Oxenstierna (ca 1620) to the young King Gustavus Adolphus

|

Outstanding! Thanks!

My implementation of Meeus's algorithms and tables from Astronomical
Algorithms is giving me positions of the celestial bodies within an
arcsecond for everything except the moon, where I'm seeing errors of over
ten arcseconds in declination in some testcases (Meeus says the error in
declination should generally be no more than four arcseconds). While ten
arcseconds is more than good enough for any celestial navigation application
(hell, 30 arcseconds would be good enough!), still I'd like to get the moon
right too. No doubt the NOVAS code will do the job.

Thanks again,
Tom Dacon

"Vic Fraenckel" wrote in message
...
Tom Dacon wrote:
| Hal, do you have a link to somewhere that has the NOVAS code?

Try
http://aa.usno.navy.mil/software/novas/novas_info.html

HTH

Vic

--
__________________________________________________ ______

Victor Fraenckel - The Windman
KC2GUI
www.windsway.com

Home of the WindReader Electronic Theodolite
Read the WIND

"Victory at all costs, victory in spite of all terror, victory however
long
and hard the road may be; for without victory there is no survival."
- Winston [Leonard Spencer] Churchill (1874 - 1965)

Dost thou not know, my son, with how little wisdom the world is governed?
-Count Oxenstierna (ca 1620) to the young King Gustavus Adolphus

|