Has a shift in the sun’s current position vis-à-vis the zodiacal constellations over thousands of years cast a doubt on astrological predictions?
Director of the Nehru Planetarium N Rathnasree says: “Yes. This can be demonstrated using the Jai Prakas instrument at the Jantar Mantar Observatory once it is renovated. We will soon obtain complete calibration measurements of these instruments.”
The Winter Solstice this year falls on December 22 at 11 am, when the day is at its shortest and the night longest and the sun has reached the maximum angular distance southward of the Equator.
A few thousand years ago the Uttarayana, or northward movement of the sun following the Winter Solstice, also coincided with the entry of the Sun into the zodiacal constellation of Capricorn.
“With time, the precession of the axis of rotation of the Earth has resulted in a shift in the relative positioning of the sun in such a way that the Winter Solstice no longer coincides with the entry of the sun into the constellation Capricorn. The sun actually enters Capricorn around mid-January,” Rathnasree said.
It is this very precession that has put a doubt on the location of zodiacal constellations on which astrological predictions depend, she added.
Volunteers from the Nehru Planetarium and the Amateur Astronomers Association, Delhi are gathering at Jantar Mantar Observatory to help visitors understand the exact usage of the Jantar Mantar instruments and measure the position of the sun and its annual movement.
The exact moment when the changeover takes place between the Dakshinayana to Uttarayana around 11:37 a.m. on December 22 can be appreciated by looking at the position of the sun’s shadow on the Niyat Chakra, she said. The position of the sun’s shadow on this scale should be 23.5 degree south of zero on the scale.