Considerations about OrbUpdated November 30, as promised
Orb is a convenience. It helps astrologers make order among many, many degree distances. Theoretically, holistically, everything in a horoscope is in aspect with everything else, to one degree or another (no pun intended). The entire behavioral and value-judgement system of the human being works within some homeostasis, some balance and routine molded throughout the early years of life, that promises efficiency and predictability. When that balance is upset, all faculties are commandeered to set it right, or else divergent or aberrant behavior itself emerges and founds a new persona.
We astrologers find the individual best way to set up guidelines for the aspects we use. I am asked often about orbs ---and remember there is no REASON for this orb or that orb; it is entirely a personal choice for organization among myriad possibilities- and I share my personal choice here: I feel that the tighter the orbs, the fewer the aspects we record, the more reliable those recorded aspects are in guiding a rich, insightful analysis.
Specifically, I tell my computer to use 6.5 degrees for the Sun or Moon, 5 degrees for the other planets in relation to each other and to the MC and ASC; 3 degrees for the semisquare and sesquiquadrate; and 2 degrees for the quintile, the very important quindecile [see archives of "Analytical Techniques" in this website], and the quincunx.
This concept of tight orbs keeps the aspect grid uncluttered. -And, I should include here the rhetorical questions, "And just how many aspects do we need anyhow?" They all tend to say the same thing as an extension of the first impression (from Hemisphere Emphasis, keys like Saturn retrograde, etc.) [See aforementioned archives here as well.]
There are exceptions, of course. Just as there are no cusp lines in the brain, and one House spills over into the next (which really discards so much of House-system discussions, wherein the focus is only on internal House cusps since the Midheaven and Ascendant are the same in all Systems, except Equal House), so there is no barbed-wire fence between behavioral faculties and thought processes. If I want to curtail my off-the-wall tendencies in correspondence with my Uranus peregrine (just an example here), I can simply reach out, figuratively, to get my Saturn and bring it smack dab onto my Moon (even though they are natally not in aspect): I would be summoning the dignity necessary for my visit to the bank's loan office, to make the right impression there, although that's not the way I normally express myself! --This is called behavioral modification, an established therapy used by everyone in one way or another, at one level of knowing or another.
As I have been teaching for years, the concept of orb actually becomes a span of consciousness; some people can reach out and make a conjunction between Venus and Saturn, say, 10 degrees away natally, in order to affect an economy of socio/emotional energies for one reason or another. [Remember Mother Theresa built her Venus-Saturn square into a celibate, selfless altruism that eventually will earn her sainthood!] --These are astrological adjustments made through the client's reality disclosure, not through some astrology rulebook, trying to grasp the impossible.
Another concept is what I call "Time-Orb". This is the concept that reflects the gradualism that attends almost all happenings and change in our life (this side of accidents). The Time-Orb of a Solar Arc, for example, is tight: 1 degree; but that 1 degree is one year in time translation. AND, during that background arc's application-partile-separation process, we have a Time-Orb of one year that will witness the trigger transit, a transit of importance (usually to an Angle or Sun or Moon) that will bring everything to a head. The same can be said about the Secondary Progressed Moon (and, indeed, angular hits in Tertiary Progressions), a very reliable trigger.
Get the "feel" of orbs. It's a "feel" you get with experience; your orb references for your eyes are your analytical faculties expressing themselves, just as your House system of choice is! These things reflect your space-time continuum, the lens through which you see life in development. There is no law, no dogma. Relax: knowing these concepts, allow your creativity to bloom freely and individualistically within the guidelines you assimilate through your studies.Next Update: December 30