The sextile and quincunx are considered as the 'border' aspects in-between major and minor ones. Most of the astrologers consider the sextile (60°) as major aspect, while quite a noticeable group uses the quincunx aspect (150°) as major, only a very small minority considers the semi-sextile (30°) as a major aspect. All major aspects, along with these three 'border' aspects, are called the 'Ptolemaic aspects'.
The quincunx (or inconjunct, abrv. Inc) is an angle of 150°, which is five-twelfths of the 360° ecliptic. A separation of 150±2° is considered a quincunx. The quincunx is said to be of moderate but somewhat unpredictable influence, bringing strain. It indicates difficulty and stress, due to incompatible elements being forced together. It can mean an area of self neglect in a person's life (especially health), or obligations being forced on a person. This aspect is also sometimes called the inconjunct, though this usage is technically incorrect.
The semi-square (abrv. SSq) is an angle of 45° (1/2 of a square [90°]). A separation of 45±2° is considered a semisquare. This aspect is considered a weaker version of the square and indicates somewhat difficult circumstance. It is sometimes known as the octile or semiquartile.
The sesquiquadrate (abrv. Ses) is an angle of 135° (a square [90°] + a semisquare [45°]). A separation of 135±2° is considered a sesquiquadrate; it indicates somewhat stressful conditions. it is considered similar in influence to the semisquare. The sesquiquadrate is sometimes called a sesquisquare, square-and-a-half, quartile-and-a-half, and/or trioctile.
The semi-sextile (abrv. SSx) is an angle of 30° (1/2 of a sextile [60°]). A separation of 30±2° is considered a semisextile. This aspect signifies a weak strain connected with making decisions, and indicates an area of life where a conscious effort to be positive will have to be made. Alternate names include confinis and inconjunct.
The quintile (abrv. QNt or Qui) is an angle of 72°, i.e. the angle for a regular pentagon. A separation of 72±2° is considered a quintile. This aspect is considered somewhat similar to a semisextile (moderately beneficial), but effort is not needed to reap its benefits. Indicates talent and vaguely fortunate circumstances.
The biquintile (abrv. BQt or BQn) is an angle of 144° (a quintile [72°] x 2 = 144°). A separation of 144±2° is considered a biquintile. This is considered similar to a quintile.