Analemma

Analemma

To be read in conjunction with Temple Astronomy 5 

An analemma is the figure-eight curve that traces the Sun's position in the sky at the same time of day throughout the year. It accounts for the Equation of Time (the difference between solar time and clock time) and the Sun's declination

A lunar analemma is a composite figure-8 or teardrop curve traced by the Moon in the sky when photographed from the same exact location at the same time every day for a lunar month (approximately 29.5 days

Distinction from Solar Analemma: Unlike the solar analemma, which plots the Sun's position over a year, the lunar analemma tracks the Moon over approximately one month. The photograph has to be taken 50 minutes and 29 seconds later each day to see the Moon in the same place.

 The figure 8 shape of the analemma is due to

 North-South Motion (Latitude Shift): The Moon's orbital path is tilted by about 5 degrees relative to Earth's ecliptic plane. As the Moon revolves around Earth, it wanders North and South of Earth's equator. This movement drives the vertical elongation of the figure-8 loop.

East-West Motion (The Equation of Time Shift): The Moon travels on an elliptical—rather than a perfect circle—orbit. Per Kepler's laws, the Moon accelerates when it is closer to Earth (perigee) and slows down when it is farther away (apogee). This varying speed causes the Moon to arrive slightly early or late within its designated 50-minute-delay window, creating the horizontal width of the loop.

The phases of the moon will be seen along this figure of 8. However, if we have to make an analemma of the full moon phase, then the result will not be a figure of 8 but a curve. Why?

 Seasonal Shift Full Moons are opposite the Sun; their positions perfectly invert the seasons. A summer Full Moon stays very low to the horizon (mimicking a winter Sun). Conversely, a winter Full Moon rides incredibly high in the night sky (mimicking a summer Sun). This 12-month cycle creates the vertical height of the analemma.

Tilt of the Moon’s orbit. The Moon’s orbit is tilted about 5.15 degrees relative to Earth's orbital plane (the ecliptic). Because of this tilt, the Moon doesn't follow the exact same path as the Sun. Each month's Full Moon drifts slightly East or West of the central meridian line, forming the horizontal thickness of the curve

 The size of the full moon will not be the same. It will depend upon the apogee and the perigee of the orbit. There will be 12 to 13 full moons, which gives the reason for Adhik Maas adjustments in the Hindu calendar.

The location on the Earth decides the angle of the curve of full moons. In the Northern hemisphere, the winter full moons will be high above the horizon as compared to the Summer full moons.

Therefore, at the Swarg mandap of Kopeshwar temple, the full Moon is seen on Tripoori Purnima, which is the winter full moon, high in the sky. Hence, it is visible through the Swarg Mandap.

For 2026, the full moon will be on 24 Nov 2026 at a maximum nightly altitude of 85 degrees. See diagram below

 When standing inside the structure on the Rangshila stone and looking straight up through the open ceiling, the Full Moons of 2026 will trace three distinct paths:

• The Central Axis Overlap (November 24, 2026 — Kartik Purnima): This is the precise night of the historical alignment. As the moon transits the local meridian around midnight, it passes through the absolute dead centre of the 13-foot circle. The cold moonlight falls as a clean circular beam, completely covering the Rangshila slab below.
• The Northern Shift (March 3 & September 26, 2026): During the spring and autumn equinox phases, the Moon drifts northward. It does not cross the centre point; instead, it cuts an offset path across the upper northern half of the open stone ceiling frame.
• The Southern Skim (May 31 & June 30, 2026): During the summer months, the Full Moon stays incredibly low on your southern horizon. From inside the mandap, the Moon will skim along or below the lower southern edge of the oculus beams, remaining mostly hidden from the central viewing floor.