Hi NR,
You ask good questions!
An aspect can't perfect if the planets have to change signs to do it; this is seen as an impediment or prohibition to perfection. The only possible exception would be the Moon, if she is in late degrees and immediately aspects a planet from the next sign; in this way she is said not to be Void of Course.
A planet having to change signs in order to perfect *can* be seen as 'a change of circumstances before it happens'. In the case of Venus and the Sun, however, since the aspect doesn't perfect for such a long time, more than halfway through the next sign, we have to ignore this 'rule' entirely: in the eyes of a horary chart, Venus and the Sun will 'never' perfect, at least for the question at hand. The conjunction is just too far away. This wouldn't be considered a fortunate aspect anyhow, as Venus loses all of her dignities in Gemini and so has no power to protect herself from the Sun.
If Planet A reaches Planet C before Planet B does, this is also prohibition. So the Moon reaches a planet before Venus does; unless there is translation of light from the Moon to Venus to the Sun. But again, a change of signs means that the aspect doesn't perfect. If it's not going to perfect in the chart in front of you, it's not going to perfect.
There is a real cautionary tale about extrapolating what will happen 'when this happens to Planet A', especially if it happens only when the planet changes signs. Horary deals with the
immediate, so the fact that a planet reaches another planet's terms in 21 degrees or so, is basically a hiding to nothing. Looking at the present moment, Planet A
isn't in Planet B's terms, and so it can't be considered as a factor.
We can't look at a horary chart like a developing movie plot, in other words. Horary is more like a still-shot than a film; it captures the essence of the situation at the moment you ask the question, because life is meant to be lived moment-by-moment, without the heavy focus (some might say obsession) with
what's going to happen next.
You can get general trends from immediately-applying or separating aspects; so in this way you can see that you will or won't get the job, for example; or that he will or won't come back to you. But reaching any further than that, to see what the job will be like a year from now, or whether he is in fact going to go back to his ex-girlfriend sometime next March, is an exercise in futility, much like 'guessing' what will happen when such-and-such planet reaches the degree of its exaltation, halfway through the next sign along; there is a great deal of Free Will at play in our lives.
Did that help?
Cheers,
AG
opposite natal
/ transit 
conjunct natal
square
inconjunct
Linear Mode
