From: kap@eng.cam.ac.uk (Kevin A. Price)
Newsgroups: alt.astrology
Subject: Re: Declination vs Latitude
Date: 12 Oct 92 16:02:10 GMT
Organization: cam.eng

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From: Rich Adams <rich@com.convergent.go_unix>
Message-Id: <9210121510.AA00042@go_unix.Convergent.COM>
Subject: Re: Declination vs Latitude
To: kap@uk.ac.cam.eng (Kevin Price)
Date: Mon, 12 Oct 92 8:10:05 PDT
X-Mailer: ELM [version 2.3 PL11]
Status: RO

I received this from Rich Adams.....

*******************************************************************************

Kevin,

I have read Walter's response to  my request and am afraid he feels I've
flamed him.  Please post this response to alt.astrology.  I for one
don't want to start any flaming, I simply want the record set straight.

Thanks again for your help.
/************************************************************************/

Walter,

Thanks for taking the time to respond to my post.  I apologize if you
felt I was flaming you, that was certainly not my intent.  I for one am
very grateful for work you have put into astrolog and for sharing it
with others. My post, as I stated, was intended to point out the problem
and help get it resolved.

I have included below the routine I wrote based upon Meeus' book for
converting planetary latitude (measured from the ecliptic) to
declination (measured from the equator). The practice of geocentric
astrlogy is by definition from the earth point of view. Determination of
parallel aspects by declination is not the same as by planetary
latitude.

In may ways, we could use the analogy of binary vs hexadecimal vs octal;
they are simply different ways of looking at the same number.  In the
same way we could draw that analogy between planetatry latitude and
declination.  However, if we compare hexadecimal with octal, they don't
look the same.  When I compare charts of other geocentric astrologers to
my own, I need a common point of reference, and the conversion between
planetary latitude and declination is not one I can do in my head.  And,
if I have a chart which says Declination, I tend to think that's what it
is.

One other point regarding accuracy, when doing progressions, an error of
only 15 minutes of arc can make an error of greater than a year in
prediction.  You can draw your own conclusions about the importance of it.
I for one prefer the accuracy.

In any event, Walter, thank you for your efforts.  I am simply sharing
with you what I have found in the spirit of what you have started.
Please accept my thanks, and here, below is the routine for converting
planetary latitude to declination.

/**********************************************************************/
/* Note: this takes the planetary latitude array: planetalt[] and     */
/* converts those values to declination in the array: decl[]          */
/* you need to declare that array globally                            */
/**********************************************************************/

void declin(int i)   /* RA & decl1ination routine */
{
double  dq, dw, dx, dy, dL, dB, dO, dG, deg;
dw = 0;  /* this will change ecliptic to equator */
	/* set w = 1 for equator to ecliptic */

  deg = planetalt[i];
  while (deg > 90.0)    /* Make sure declination value is from -90..+90 deg. */
    deg -= 180.0;
  while (deg < -90.0)
    deg += 180.0;


	dO = OB;

	dL = DTOR(planet[i]);      /* convert to radians */
	dB = DTOR(deg);

	dq = sin(dB) * cos(OB) + cos(dB) * sin(OB)*sin(dL);
	decl[i] = asin(dq)*180.0/PI;


}



regards

Rich
rich@convergent.com