Is the chart diurnal or nocturnal? 1 by Mark Like many I had always naively assumed a diurnal or nocturnal chart was simply determined by the Sun rising or falling below the ASC/DESC axis. However on a related thread a member drew my attention to this piece on Nina Gryphon's blog: I wish to clarify, though, that a chart can be diurnal even though the Sun is quite a bit below the horizon. For me, civil twilight (Sun less than 6 degrees under the horizon) is daylight. Some astrologers are even more lenient, and include nautical twilight (6-12 degrees below the horizon) as daytime. (Nina Gryphon) http://gryphonastrology.com/blog/2008/0 ... /#comments The issue of whether a chart is nocturnal or diurnal is crucial to hellenistic and medieval astrology. Would these astrologers have adopted the same approach here? Quote Wed Sep 10, 2008 1:43 pm
2 by leywand Hi Mark As for me I?m not convinced by Gryphons interpretation. I?ll stick to the "simple" approach. Nighttime chart is when sun is in house 6 below the DC, because only this approach is consistent with the planetary hours, measured from sunrise to sunset (and vice versa). Right after sunset the first planetary hour of the night begins -> nightchart. I didn?t come across any traditional sources speaking of civil or nautical twilight in determining a nightchart. Quote Wed Sep 10, 2008 2:41 pm
3 by Mark I didn?t come across any traditional sources speaking of civil or nautical twilight in determining a nightchart. Yes I guess that bit of Nina's comment is less relevant to traditional astrologers! I assume the latitude on earth of the observer will directly impact on this issue too from a visual perspective? Quote Wed Sep 10, 2008 3:13 pm
4 by Astraea Hi Mark. At an astrology conference, I asked Rob Hand at what point the chart is classically considered diurnal, and he said that it is whenever the sky lightens, because at that point the Sun's rays are visible, even though his body is not. So the Sun can be below the horizon, and the chart still be considered diurnal. Quote Wed Sep 10, 2008 3:37 pm
5 by Mark Thanks Astraea, I thought that might be the traditional outlook. That just leaves us with the tricky issue of deciding when that is from our basic astrology software? I am not sure how accurate Nina Gryphon's 6 degree rule of thumb is likely to be in reality. However, I note Leywand ties this to planetary hours so maybe this approach has some credibility? If not, does this mean hellenistic enthusiasts should be checking out good astronomy software for such charts? Quote Wed Sep 10, 2008 4:06 pm
6 by Astraea Six degrees would work out to about 24 minutes of time, so Nina's rule of thumb might be accurate in a general sort of way. On the other hand, when so much depends on whether a chart is diurnal or nocturnal, it's crucial to get it right. Some computer programs allow one to come pretty close. I use Solar Fire most of the time, and it allows me to select either "visual" or "actual" in its rise/set module for any planet. This is where I go when the Sun is close to the horizon, but not there yet. It's not a perfect solution, but still much better than guessing. Janus probably has a similar option, though I've not checked. Quote Wed Sep 10, 2008 4:29 pm
7 by Astraea Hi Steven, he gave me that information at ISAR 2000 and I don't see a discrepancy between what he said then, and the quote you provide. But I bow to you in this matter as well as in others, you are someone whose scholarship I deeply respect and appreciate. Quote Wed Sep 10, 2008 5:16 pm
8 by margherita leywand wrote: I didn?t come across any traditional sources speaking of civil or nautical twilight in determining a nightchart. Bezza writes the same about twilight. I think because they think that astrology is more than a printed chart, it is something you can see in the sky so when there is the light is a daychart, if not a nightchart. Anyway in the case of Obama I vote for a night chart, 6 degree below the horizon are a lot to me. Quote Wed Sep 10, 2008 5:30 pm
9 by Astraea Steven, thank you so much for your detailed explanation of these issues - I have learned a great deal and now have a clearer understanding of what's involved. Again, thank you! Quote Wed Sep 10, 2008 8:02 pm
10 by Mark Hello Steven, Thank you so much on that extremely detailed response. I suppose the only question that still occurs to me is what astronomical software to you recommend for this purpose? Quote Fri Sep 12, 2008 11:50 pm
11 by Gem I read the thread with much interest as someone who has natal Sun about 7degs below the AC. My chart must be technically nocturnal yet I personally find employing more flexible approaches/interpretations for natives born during the twilight hours makes good sense, as Nina did with Obama's chart. In my case, to give a couple of examples, the daytime order of tripricity rulers describes my life perfectly while the nocturnal order of Firdaria makes better sense. Gjiada wrote: astrology is more than a printed chart, it is something you can see in the sky so when there is the light is a daychart, if not a nightchart. I agree though I suppose the Sun's influence increases by the minute at dawn while at the sunset the Moon's grows stronger than the dying Sun Quote Sat Sep 13, 2008 3:29 pm
12 by Andrew Bevan I also read in one of the classic standards in my posession (can't remember off hand) that the Sun ruled the twilight or dusk, but I would stick to the conventional definition of whether the Sun was above or below the rational horizon! Great question! On the cusp of Daylight! Stephen said: Astronomical Twilight is the period when the center of the Sun is between 12 and 18 degrees below the horizon. Up beyond the Artic Circle we have extented periods of twilight due to the elognation of the equator with the rational horizon. That sure does create some interesting play of light, but assuming that the Sun did not rize above the horizon - would there still be accounted a diurnal period? Last edited by Andrew Bevan on Sun Sep 14, 2008 4:32 pm, edited 3 times in total. http://www.astronor.com Quote Sun Sep 14, 2008 4:06 pm