The problem with orbs is that astrologers don't generally agree on how many degrees should be allowed for each type of aspect. In The Inner Sky, astrologer Steven Forrest writes: “No orb can be defined rigidly. To attempt to nail them down is like trying to determine the exact day on which your kitten became a cat. It doesn't work.”
Astrologer Robert Hand considers smaller orbs to generally be more accurate, but is rather philosophical about the whole issue. In Horoscope Symbols, he writes: “What the question boils down to is not how far out of orb an aspect can be and still have an effect, but rather how subtle a linkage one will accept as significant.” In other words, with practice, you'll arrive at your own sense of how large or small an orb should be.
Astrologer Robert Hand tends to use relatively small orbs: five degrees for all major aspects. One of his exceptions to this rule is to use orbs wider than five degrees when a chart doesn't have many tight-orb aspects. This was his solution to the problem.
Rose Lineman and Jan Popelka, writing in Compendium of Astrology, use an eight-degree orb for conjunctions and oppositions and smaller orbs for other aspects. Steven Forrest favors orbs of up to five degrees. Although he feels that orbs of six and seven degrees should still be considered, he believes their impact is considerably less. In Forrest's opinion, orbs of eight or nine degrees hardly count. But if an aspect involves the Sun or the Moon, he recommends allowing a wider orb by one or two degrees.
Planets and Orbs
In the past, astrologers assigned particular orbs to particular planets. A Jupiter aspect, for instance, was allowed an orb of ten degrees, which is very wide, considering that the ten degrees applies on either side of the actual degree. In this system, Mercury, Venus, Mars, Saturn, Uranus, Neptune, and Pluto were permitted an eight-degree orb. The Sun got twelve degrees for an orb and the Moon eight.
Most astrology software programs work with orbs between six and eight degrees. If there aren't any tight orbs in the chart, allow orbs of five or six degrees for all aspects. Hand's orbs tend to be smaller than the norm because he uses Midpoints when interpreting a chart.
Aspects Versus Midpoints
A Midpoint is the halfway mark between any two planets. Hand, like many other astrologers, considers midpoints nearly as important as the aspects themselves. He writes: “I use midpoints because they often give information that would not otherwise be available in the chart. Without them, I have seen important characteristics of a person and events in a life completely overlooked.”
Learn about the aspects, but don't worry if it doesn't click right away. It takes time to understand these things. To simplify matters, you can choose to focus on one particular area. For example, astrologer Grant Lewi only stuck to the broad strokes in horoscope interpretation. The Sun, Moon, and major aspects were enough for him.
The bottom line is that you can talk to ten different astrologers and get ten different answers on the issue of orbs. This is one of many gray areas in astrology that your own experience will determine for you. Think of this book as a reference manual to guide you as you learn what you'll be personally comfortable with.