Midheaven
The Midheaven (MC) is the highest point the ecliptic reaches over your meridian: it represents vocation, work, and public standing, and it begins house 10.
The Midheaven, or Medium Coeli, is the place in the sky the Sun passes through at noon: the degree of the ecliptic culminating over your meridian at the exact moment of birth. It is the highest point of the chart.
Unlike the Ascendant, which depends on the horizon, the MC depends on the meridian: the line running north to south through the zenith. Both move with the hour, but not at the same rate.
What the Midheaven describes
Vocation and work: not the daily job—that is house 6—but what you are known for. The place you occupy in the social structure.
Reputation: what is said about you when you are not there. The tradition also read it as dealings with authority and the favor of the powerful.
And a parental figure: Hellenistic doctrine tends to read the mother in house 10 and the father in house 4, although much of modern astrology reversed that assignment.
The MC does not always begin house 10
This is the technical point that causes the most confusion. In quadrant systems (Placidus and the like), the MC is by definition the cusp of house 10.
In whole-sign houses, it is not. The MC falls where it falls, and it can land in house 9, 10, or 11 depending on latitude and time. The Hellenistic tradition then treats it as an independent sensitive point: it still signifies vocation and public life, but it does not define a house.
That is not a flaw in the system: it is a real difference of doctrine, and it is worth knowing which one is in use before interpreting.
Frequently asked questions
What is the Midheaven in astrology?
It is the highest point the ecliptic reaches over your meridian: the place the Sun passes through at noon. It represents vocation, work, and public standing, and in quadrant systems it begins house 10.
Is the Midheaven always house 10?
Only in quadrant house systems, such as Placidus. In whole-sign houses the MC can fall in house 9, 10, or 11, and it is treated as an independent sensitive point.
What is the difference between the Midheaven and house 6 regarding work?
The Midheaven is recognition and vocation: what you are known for. House 6 is the concrete daily task: the schedule, the routine, the subordinates.