Abscission of Light

Definition

Abscission of light is one of the ways a horary chart says no. Two significators are moving toward each other, but a third planet completes its own aspect to one of them first, stepping in between the pair and "cutting off" the light that linked them. The Latin abscissio means "a cutting off" and names the blocking event itself; it belongs to the broader family of prohibition. Two close relatives differ in how they break the link: in refranation a significator turns retrograde before completing, and in frustration the slower significator perfects with a different planet first.

In Tradition

In medieval Arabic and Latin horary practice, abscission is read as one of several formal blocks to perfection that cancel or delay the matter the question is about. Bonatti and Lilly treat it together with refranation and frustration as part of one connected catalogue of impediments — the things that get in the way — on which the horary verdict of "will it come to pass?" depends.

In Practice

Once the two significators are set — Lord of the Ascendant for you, the querent, and Lord of the topical house for the quesited — and their approaching aspect identified, the astrologer scans for any faster planet that will complete its own aspect to one significator before the pair can perfect. If one exists, the matter is judged abscinded — interrupted, blocked, or redirected. The house that abscinding planet rules describes the person or circumstance behind the obstruction: a malefic (a difficult planet) in poor shape reads as a severe block, while a benefic that is in sect (working in its preferred day or night chart) reads as a softer delay that may still resolve through translation of light. Abscission is kept separate from refranation, where the original significator turns retrograde, and from frustration, where the slower significator engages a different planet first; all three are weighed alongside reception and exaltation rescues before the final judgment.

Historical Origin

The doctrine descends through the Arabic-Latin horary chain — Sahl ibn Bishr, Masha'allah, and Bonatti's Liber Astronomiae (13th century, Vol XI Part III) — into William Lilly's Christian Astrology (1647). Bonatti distinguishes abscission (cutting-off) from return-of-light (redditus luminis) and gives a worked Sun–Saturn–Jupiter example.

Etymology

Origin: Latin. Meaning: From abscissio (a cutting off), from abscindere (to cut away, tear off). The image is of light being severed mid-transmission..

Further Reading