49 by rob Hi, I also would like to thank Petr for clarifiying this PD. In order to get this PD in Morinus you have to set: - Placidian (Under The Pole) PD-System - ASC-MC as promissors - Opposition aspect - Aspects of Promissors to Sigs - Sun as Significator Since the promissor is the moving point and in the PD in question we want to move the MC/IC(promissor) to the Sun(significator). Rob Quote Tue Jul 20, 2010 4:39 am
50 by rob "Promissors to aspects of sigs" can also selected. In the PD- range dialog: 0-100, converse(or both). Rob Quote Tue Jul 20, 2010 5:00 am
51 by Bulletbobb This is almost off-topic, but since it's my thread.... I've been experimenting a bit with the Astro program, and thought it would be nice if I could do up a proper triwheel in SF for a particular event, the graphics in Astro being a bit primitive. I thought that, since PD's are directions, I could just measure the arc through which any one planet was directed in Astro, then enter this value in SF in the user arc section and I would have a chart I could put into a bi- or triwheel. Note that these are the positions for a given date, which is why I thought they would all be the same. Trouble is, it doesn't work. It seems that the planets in the example in Astro have been directed through arcs ranging from about 14? to 19?. Could someone offer a simple explanation of this? Bob Quote Tue Jul 20, 2010 7:16 pm
52 by Martin Gansten Bulletbobb wrote:Could someone offer a simple explanation of this? The simple explanation is that primary directions are not calculated in degrees of ecliptical longitude ('zodiac degrees'). Quote Tue Jul 20, 2010 8:50 pm
53 by Bulletbobb Right ascension, right? Back to the drawing board. Thanks, Bob Quote Wed Jul 21, 2010 12:32 am
54 by GR Bulletbobb wrote:Right ascension, right? Back to the drawing board. Thanks, Bob Well Bob, the more complete answer would be that points other than the Asc and MC would be directed by some proportional arc between the oblique and right ascensional circles; the manner of proportion is the one that is often debated. Gabe Quote Wed Jul 21, 2010 2:31 am
55 by Bulletbobb I guess the shortest form of the answer is that my idea of fooling Solar Fire into thinking the PD positions are SA positions isn't going to work. Still hard to see why it won't, however. If the heavens (or the planets/angles) wheel around as a unit, as they do in all (?) types of directions, then there should be some value I could plug into the SF user arc to get them where I want them. I guess I'll have to settle for putting my natal chart in the senter of a blank triwheel and entering the directed positions in by hand. Like the good old days before computers! Bob Quote Wed Jul 21, 2010 12:33 pm
56 by Atlantean Hello Bulletbobb, It SEEMS that it would work, but it doesn't... Those user arcs are going to be moved in longitude. The math for the user arcs is linear, not so for the Primary Directions. The Primary Directions are a spherical-geometric construct. In this case, it really is apples and oranges... Peace Atlantean Quote Wed Jul 21, 2010 1:50 pm
57 by Ed F Another way of putting it that might help is that primary arcs are along circles of declination and positions move with the earth's rotation. The ecliptic is at a roughly 23 degree angle to the equator, so when you translate primary positions to their zodiacal equivalents, the same proportional distance on two different declination circles will differ on the zodiac (same right ascension, but different declinations). Solar arc directions are just a straight addition of an arc to all positions in zodiacal measure. I'm not even sure why the two things share the label of "direction" since they're such different beasts. (Well, actually I do know why: they both supposedly ignore proper motion of the planets. But I consider that pretty weak). - Ed Quote Wed Jul 21, 2010 2:58 pm
58 by Martin Gansten Ed F wrote:Solar arc directions are just a straight addition of an arc to all positions in zodiacal measure. I'm not even sure why the two things share the label of "direction" since they're such different beasts. (Well, actually I do know why: they both supposedly ignore proper motion of the planets. But I consider that pretty weak). Very weak, and quite a recently invented distinction. It would be interesting to research the historical changes in the use of the terms 'directions' and 'progressions' (along with some others). Today's 'secondary progressions' were 'secondary directions' to Placidus (who invented them) and to several subsequent generations of astrologers. Quote Wed Jul 21, 2010 8:39 pm
Error in computational methods Topocentric Primary Direction 59 by Ursa Major I think that one of the reasons that calculation of the Topocentric Primary Directions with Morinus is, that Morinus does not give the correct Oblique Ascension: According Morinus 2.9 it will give you 23 deg 26 min 40 seconds, but it had to be 23 deg 26 min 50 seconds for the year 1940. Another example: The year 1951 according Morinus 23 deg 26 min 53 seconds, but it had to be 23 deg 26 min 44 seconds. Quote Wed Jul 28, 2010 10:21 pm
60 by Ursa Major Steven, Yes, you are right I must be obliquity of the ecliptic, but the difference is not 0.2 seconds but almost 10 seconds. The simple astronomical formulae, where T is measured in Julian centuries from 1900 23 deg 27' 8.26" - 46.84" * T - 0.004"* T^2 + 0.0018" * T^3 gives for: 1940 23 deg 26' 49.52 " 1951 23 deg 26' 44.37 " Another formules are in the sources from Morinus swephlib.c and swephlib.h ( function swi_epsiln( double J ) ) Quote Thu Jul 29, 2010 11:16 pm