Every aspect between every pair of planets.

An aspect is the angular relationship between two planets in a chart, measured in degrees of the zodiac. The five major aspects are conjunction (0°, blending), sextile (60°, supportive), square (90°, tension), trine (120°, harmonious), and opposition (180°, polar). Aspects describe how two planetary functions interact — whether they cooperate, compete, blend, or stand in productive contrast.

The orb (allowable distance from exact) varies by aspect and tradition. Modern Western astrology typically uses 8-10° for conjunctions/oppositions, 6-8° for trines/squares, and 3-4° for sextiles, with personal-planet aspects (Sun, Moon, Mercury, Venus, Mars) given wider orbs than outer-planet aspects. Tighter aspects feel more pronounced; aspects within 1° of exact are read as constitutional rather than situational.

No aspect is bad, but the five major aspects do have different qualities. Squares and oppositions create tension and require integration work; trines and sextiles flow more easily. The classical reading is that 'difficult' aspects produce growth and 'easy' aspects produce comfort — both are necessary, and a chart with only easy aspects often produces less actualized people than one with productive friction. The trick is working with what each aspect asks for rather than wishing it were different.

Both. Each aspect has its own meaning that's worth understanding directly — these reference pages exist for that. But aspects don't act in isolation; they interact with the signs each planet occupies, the houses each planet rules and falls in, and the larger patterns (T-squares, grand trines, yods, stelliums) the whole chart forms. Read the individual aspect to understand the dynamic; read the whole chart to understand how that dynamic actually expresses in your life.