Only the five Ptolemaic aspects are used in traditional astrology and their application also differs to modern mainstream astrology disciplines. Aspects have no quality of their own, they cannot denote whether the event that will manifest is good or bad, they simply show whether that event will occur with ease or with difficulty; aspects are the doing words of astrology, hence they are verbs. To determine the quality of the event we need to assess the dignities of the planets in question together with the receptions between the two planets.

The 5 Ptolemaic Aspects

• Conjunction: planets need to be in the same sign to form a conjunction; while technically not an aspect because the planets are joined bodily, it is viewed as one to simplify matters. 
• Sextile: planets are 60 degrees or 2 signs apart; a sextile is in essence is a weak trine and bring planets together easily.
• Square: planets are 90 degrees or 3 signs apart; these signs are of the same mode: cardinal will square cardinal.
  
• Trine: planets are 120 degrees or 4 signs apart; these signs are of the same element: fire will trine fire. A trine brings the planets together with ease.
• Opposition: planets are in signs that oppose each other, thus are 180 degrees apart.

The Opposing Signs

This sphere is 360 degrees in circumference, divided into 12 sections of 30 degrees each. Each section is allocated one of the zodiacal signs, commencing at Aries and ending with Pisces. The signs that oppose each other are: Aries - Libra; Taurus - Scorpio; Gemini - Sagittarius; Cancer - Capricorn; Leo - Aquarius; Virgo - Pisces.