Eclipses in the Vedic Planisphere: The Moon Above the Sun

This question addresses a key challenge in the Purāṇic cosmological model, where the Moon is often described as being situated "above" the Sun in a concentric, layered system. If this is a literal, vertical arrangement, how can the Moon pass into the Earth's shadow (Lunar Eclipse) or the Moon block the Sun (Solar Eclipse)?

The resolution lies in understanding the two distinct ways to interpret the model:

1. The Vertical Cosmos (Literal Layered Structure): In this view, "above" refers to a higher plane of existence or a more subtle dimension.

2. The Planisphere (Celestial Map): In Richard L. Thompson's view, the "above and below" is a cartographic convention on a flat projection, representing angular distance from the celestial pole (Mount Meru).

The Literal Layered Model Explanation

In the literal Purāṇic model, the orbits are not considered perfectly coplanar like in modern astronomy. The "above" and "below" do not necessarily prevent alignment because the system is three-dimensional.

A Lunar Eclipse occurs when the Moon, the Earth's shadow, and the Sun all align on a common line of sight. Even if the Moon is on a higher plane, it can still pass through the long, cone-shaped shadow cast by the Earth into space.

A Solar Eclipse is more complex. For it to occur, the Moon must pass directly between the observer on Earth and the Sun. In the literal layered model, this is explained by the concept of the Moon's path having a "descending node" where its orbit dips down to intersect the line of sight between the Earth and the Sun. The texts describe a shadow entity, Rāhu, which is responsible for causing eclipses by intermittently obscuring the Sun and Moon.

The Planisphere (Thompson's Model) Explanation

This view provides a more direct and geometrically consistent explanation. In a planisphere view, "above" and "below" are not absolute vertical positions but are positions on a 2D map.

On this celestial map:

Mount Meru at the center represents the North Celestial Pole.

The concentric rings represent lines of celestial latitude (declination). An object "higher" or closer to Meru is at a higher declination, closer to the celestial north pole.

The Sun and Moon both travel on their own off-centered circular paths (their respective ecliptics) around this central point.

In this context, eclipses are perfectly possible because:

The paths of the Sun and Moon intersect at two points called the nodes. These are the points where the two circles on the planisphere cross.

An eclipse can only occur when a New Moon (for a solar eclipse) or a Full Moon (for a lunar eclipse) happens very close to one of these nodal points. At these precise moments, the Sun, Moon, and Earth are aligned in space, and from the perspective of the 2D map, their symbols overlap.

The statement "the Moon is above the Sun" on the planisphere simply means that the Moon's average path on the celestial map is at a slightly higher average declination (closer to the polar center, Meru) than the Sun's path. It does not mean they cannot ever align from our viewpoint on Earth.

Conclusion

In both interpretations, eclipses are not only possible but are a predicted and integral part of the cosmology.

In the literal model, it is explained by the three-dimensionality of the orbits and the specific action of Rāhu at the nodes.

In the planisphere model, it is a straightforward geometric consequence of the Sun and Moon's paths intersecting on the celestial map. The "vertical" arrangement is understood as a feature of the map's coordinate system, not a physical barrier to alignment.