The Tropic of Capricorn is

The two tropics are the latitude parallels marking Earth's axial tilt (obliquity) from the equator — the northernmost and southernmost points where the Sun can stand directly overhead at solar noon. Earth's obliquity is close to 23.4° (23°26′); geography textbooks and exams conventionally round this to 231/2° (23°30′) as the tropics' latitude. Both tropics sit at this same magnitude; they differ only in which hemisphere they lie in.

The Tropic of Capricorn is the southern member of the pair: at the conventional 231/2° S south latitude, it is the parallel where the Sun is directly overhead at the December solstice. Its counterpart at the same magnitude on the other side of the equator is the Tropic of Cancer.

• A value with no hemisphere letter (just "231/2°") cannot single out one tropic, since the north-south pair shares that exact magnitude.

• A value carrying the northern letter at this magnitude ("231/2° N") names the Tropic of Cancer, the line north of the equator — not the Tropic of Capricorn asked about here.

• A value rounded to a whole number ("23° S") keeps the correct hemisphere but drops the fractional part that fixes the conventional tropic latitude.

Cross-checking against Earth's obliquity (~23.4°, rounded to 231/2° in standard usage) and against “Capricorn” naming the southern tropic confirms 231/2° S — conventional magnitude, southern hemisphere — as the Tropic of Capricorn's latitude.