Hi Old Guy in Astrology:
Thanks for the link. Someone in the discussion gives a very nice simple explanation and purpose of it. I just use an old ephemeris and the rectify button to bring the Sun exact to the planet's degree.
As to what use it is, I think it either just further confirms and sets the understanding of that planet's role in life, or it can be said to add something more specific. For instance, my natal Uranus in my chart suggests upsets and communication breakdowns (Uranus rx ruling 3rd), but its persona chart (which btw in real time is when Uranus goes direct and exactly squares my Moon), has Mercury conjunct the DSC in the same sign as Uranus. To me that suggests that the chaos is meant to be expressed in the positive way of mentally intuiting from another source outside myself, listening closely to the "other". Yes, it was the positive expression of the Uranus in the 8th to begin with, but when the first chart says "oh, this could be bad", the second chart (in this case) says "don't worry, just listen closely and it will come to you".
Barbara Ybarra