One of the five Essential Dignities, Decan is a 10 degree subdivision of the zodiac. There are 3 Decans per zodiac sign, giving a total of 36 Decans altogether. Each Decan is assigned a planetary ruler. The Chaldean planetary sequence is the same used by planetary hour rulers, and beginning at 0° Aries is Mars, Sun, Venus, Mercury, Moon, Saturn, Jupiter, Mars, Sun, etc.
Declination is one of the measurements used to describe a planet's position in the sky using the Equatorial Co-ordinate System. It indicates a planet's position North or South of the Celestial Equator.
This is a term used to describe a horary chart cast for the onset of an illness, when the patient takes to his/her bed. The chart is consulted to determine the prognosis of the malady.
This is a small time correction used in the calculation of planetary positions. It ascertains the difference between Ephemeris Time and Universal Time (Delta T was around 61 seconds in the year 2000).
In a progressed chart the progressed Midheaven is usually linked to the secondary progressed Sun. The progressed Midheaven is then converted to sidereal time from which the progressed Ascendant is calculated and called a derived angle.
A method of house interpretation used in natal and horary astrology involving placing a house at the 1st house position and counting the other houses from this point. E.g. if the 9th house becomes the 1st house, the 10th house is the finances of the spiritual teacher. Likewise, the 11th house becomes the neighbour of the spiritual teacher.
The Descendant is where the Western Horizon intersects the Ecliptic. It is opposite the Ascendant. In most house systems the Descendant forms the 7th House Cusp. In interpretation, it describes the people an individual attracts; the partner's character; the influence others have on self (determined by sign on cusp and/or any planets near cusp).
Detriment is a term given to a planet in the opposite sign to its rulership. It is considered to be a debility and to cause the nature of the planet to be corrupted. The table below shows the signs and the planets that are in their detriment in them.
The Diamond is a mathematical point that corresponds to position of the Sun when it is at Perihelion (that point in its apparent orbit when it is closest to the Earth).
A predictive technique where all the planet positions in the natal chart are directed or advanced by the direction arc usually the secondary progressed Sun.
The dispositor of a planet is the ruler of the sign in which the planet is placed.
Example: If the Moon is in the sign of Leo then the Sun (which is the ruler of Leo) is the Moon's dispositor. However, an exception to this rule can be found if the Almuten of a planet is calculated. For example, if Saturn is at 18°AR45' the Almuten of that longitude is the Sun, not Mars, which means the Sun becomes Saturn's dispositor.
Distance refers to how far or close a planet is to the Sun or the Earth and is usually expressed in AU (astronomical units).
Diurnal is the name given to a day chart, where the Sun is above the horizon in houses 7 to 12.
Also known as Caput Draconis. The North or the Ascending Node of the Moon. The point where the Moon's orbital plane intersects the Ecliptic when the Moon is moving in a northerly direction.
Also known as Cauda Draconis. The South or the Descending Node of the Moon. The point where the Moon's orbital plane intersects the Ecliptic when the Moon is moving in a southerly direction.