Sun lines
The four lines on your map where Sun was on an angle when you were born: overhead, underfoot, rising and setting.
Sun in astrocartography
The Sun is the part of you that wants to be recognised for who you are, and the plain energy you get up with in the morning. Its four lines are easiest to picture as times of day at your birth. The MC line runs through every place where the Sun stood at noon, the IC through every place where it was midnight, and the Ascendant and Descendant lines through the places watching it rise and set. Noon is work and reputation, midnight is home and family, sunrise is your body and the way you come across, and sunset is the people who stand opposite you: partners, patrons and rivals.
None of the Sun lines is hard going, but all of them ask you to turn up. On one you tend to become more plainly yourself, which is welcome if you like who that is and awkward if you've been avoiding the question. How brightly a line works depends on the natal Sun: its sign, its house and above all its aspects. A Sun squared by Saturn still has its lines and they still count; the recognition on them comes slower and costs more.
Sun MC line: visibility and recognition
Your Sun overhead puts you in the light. Work done here tends to be seen, named and remembered, and people treat you as someone with authority before you have earned it locally.
Sun IC line: home as the source
With the Sun beneath you, identity grows from the private side of life: a home base, family, land, the work done when nobody is watching. People settle here and build something durable.
Sun ASC line: presence and vitality
The Sun rising with you here brings energy to the surface. You come across as confident and direct, you take up room, and others follow your lead without being asked.
Sun DSC line: significant others
The Sun setting puts the light on the people you meet. Partners, clients and rivals here tend to be strong characters who shape your path; relationships become the main event.
Where the lines run
Sun's declination, how far north or south of the celestial equator it sits, decides where its rising and setting lines stop: at 90° of latitude minus the declination. For births between 1930 and 2025 it ran from 23.5° S to 23.5° N, so in some charts those lines end as close to the equator as the Arctic and Antarctic Circles, for a birthday near a solstice. Beyond that point Sun didn't rise or set at all on the day you were born, while the MC and IC lines carry on to the poles.