當行星彼此形成相位時，便稱這些行星正在形成「見證」（testimony）。以下將逐一說明各種相位。
當兩個星座之間隔著三個星座，總共涵蓋五個星座時，便形成三分相（trine）。當總共涵蓋四個星座，且不計入中間的兩個星座時，便形成四分相（square）。對分相（opposition）則是指兩個相距七個星座的星座之間所形成的相位。六分相（sextile）是由兩個相距三個位置、中間隔著一個星座的星座所形成的相位。
三分相是一種親和且有助益的相位，即使其中涉及凶星（malefic），其造成的損害也會比在其他相位中來得輕微。四分相則具有艱難、不和諧且令人困擾的影響，尤其是當它涉及凶星時。對分相會帶來衝突與競爭，而當凶星參與其中時，這些情況將變得更加嚴重。六分相則是一種力量較弱的配置。
此外，觀察相位時，也必須確認它是否為精確相位（perfect aspect），亦即行星不僅在星座層面形成相位，也在確切的度數上形成相位。三分相的精確角度是120度，四分相是90度，六分相是60度，而對分相則恰好是180度。
行星之間經常在星座層面形成相位，但在度數上卻未必形成精確相位。
When planets are making angles to one another, it is said that the planets are making a testimony. Each of the angles are illustrated hereafter. A trine is created when there are a total of five signs, with the outer two signs being separated by three signs in the middle. The square exists when there are four total signs, not including the two in the middle. An opposition means that there is an aspect coming from two signs that are seven signs apart from one another. The sextile is the angle made from two signs that are three places apart, separated by one sign in the middle. The trine is a sympathetic and helpful aspect, and if a malefic is involved, it will be less damaging than it is in other aspects. The square is a hard, discordant and annoying influence, especially when it includes a malefic. The opposition creates contention and rivalry which becomes worse when involving a malefic. The sextile is a weaker configuration. It is also essential to observe an aspect, to see whether or not it is a perfect aspect, meaning that it is making an angle not only by sign, but also by exact degree. The trine is exactly 120 degrees, the square is 90 degrees, the sextile is 60 degrees, and the opposition is exactly 180 degrees. Often the planets are in aspect to one another by sign, but not by degree.