Astronomy, what constellation is the vernal equinox in now?

Actual observation! The vernal equinox is still in Aries Palace.

The origin of the vernal equinox marching westward

Before Heliocentrism's time, the ancients observed the westward shift of the vernal equinox and found precession. So precession is defined as moving westward at the vernal equinox. Because Newton solved the precession on the earth's axis, precession is defined as the precession on the point. Let's see how the vernal equinox moves westward. The ancients used peepholes for astronomical observation. Point the peephole at Aries Palace (a brighter star) at the vernal equinox. On the second vernal equinox, the peephole points to the west. After 36 years, the peephole moved 0.5 to the west, which is the origin of the vernal equinox moving to the west. In the geocentric era, people think that the earth is stationary, so the phenomenon observed through the peephole is the westward shift of the vernal equinox.

Now that geocentric theory has become history, it is necessary to re-examine the astronomical records of geocentric era. The observation peephole is fixed on the crust surface. If the crust moves to the west, the observation instrument must point to the west. Newton's precession of the earth's axis explains the observation peephole pointing west in the northern hemisphere, but it is contradictory to the southern hemisphere. If the crust moves westward, there will be no contradiction between the northern and southern hemispheres. Experiments show that the earth tide can make the crust move westward.