The rising of a celestial body when it starts to become visible after being in conjunction with the Sun is referred to as heliacal rising.
The setting of a celestial body when it starts to become visible, after it appears to be overtaken by the Sun is referred to as heliacal setting.
Half of a sphere is a hemisphere.
The great circle on the celestial sphere 90 degrees from the zenith. The ascendant / descendant axis can also be referred to as the horizon.
There are two definitions of a house ruler. According to tradition, the house ruler is the planet that rules the sign where the house cusp is located. There is also a newer definition of a house ruler which is the planet that is associated with the sign that is associated with the house. For example: Aries is associated with Mars and the 1st house so Mars is used as the ruler of the 1st house.
A planet is referred to as being in hyleg which is interpreted as "the giver of life". The Sun and Moon can be hyleg if they are in the 1st, 7th, 9th or 11th houses. All planets can be hyleg if they're between 25 degrees below and 5 degrees above the Ascendant.
The imum coeli (IC) is exactly opposite the midheaven (MC). Apparently imum coeli translated from latin means bottom of the sky (also see the astrology angles page on the website). It's derived from the Latin "imus" which means lowest and "caelum" which can mean sky or heavens.
An inceptional chart is created for the start of an enterprise such as starting a business. It's not used to choose a favourable moment to start an enterprise because that method is used in electional astrology, but the interpretation is similar.
If the movement of a celestial body is faster that is was on the previous day it's increasing in motion.
The moment a celestial body enters a sign or house is an ingress.
Planets between the Sun and Earth are inferior planets; they are Mercury and Venus.
A planet is impeded when it's afflicted by being in a square aspect, or an opposition aspect or a conjunction aspect with the malefic planets. The Moon is impeded when in conjunction with the Sun as the influence of the Sun is stronger than the Moon.
An aspect between two astrology charts where one celestial body or angle from one chart is in aspect with a celestial body or angle with the other chart. Interaspects are interpreted for a synastry (relationship) chart.
A zodiac sign is intercepted when it's contained in one house without being located at any house cusp. The signs where house cusps are located can have a stronger influcence than an intercepted sign.
See chart patterns.
The year was divided into twelve months. Every fourth year had a day added so there were 366 days in every fourth year; the other years had 365 days. The average length of the Julian calendar year was 365.25 days, it gradually became misaligned with the seasons by over 18 hours a century. The Julian calendar year was over 11 minutes longer than the tropical year (the amount of time the Sun takes to travel from one vernal equinox to the next vernal equinox).
Julian days are listed continuously without being listed in months or years. They are listed as the number of days where noon at 1st January 4713 BC is day number 1. At January 1st 1900 noon the Julian Day from January 1st 4713 BC is 2,415,020. They can also be listed from December 31st 1899 at noon. where January 1st 1900 is Julian Day 1 and January 1st 1901 is Julian Day 366 ; this method is used to make calculations easier. For example; to find the Julian Day for January 1st 1901 from January 1st 4713 BC add 366 to 2,415,020 to give the Julian Day of 2,415,386. For astronomical use the year 1 BC is followed by the year 0 then the year 1 AD. The Julian day system is not associated with the Julian calendar, it was created by Joseph Justus Scaliger in 1582; the name 'Julian' was used in honour of his father Julius Caesar Scaliger.
Latitude is the measurement in degrees, minutes and seconds of the distance north or south of a location from the equator.
Time for a location on Earth based on the mean solar day is referred to as local time. The local time changes with longitude; 15 degrees in longitude creates 1 hour difference in local time.
Longitude is the measurement in degrees, minutes and seconds of a location east of west of 0 degrees longitude. Greenwich (UK) is at 0 degrees longitude.
A term used of the ruler of a sign or a house.
A lunar eclipse is an eclipse of the Moon by the Earth. This can only happen when the Moon is full and at or near one of its nodes.
The zodiac can be divided into 28 divisions. Each division is a lunar mansion that represents the average daily distance travelled by the Moon, which is 12 degrees 51 minutes and 26 seconds. The location of each lunar mansion is a sensitive part of the chart, they're also known as critical degrees. (Also see critical degrees).
The time between two identical phases of the Moon is a lunation.