The Astrological e Magazine – July 2019

22 JULY 2019 THE ASTROLOGICAL eMAGAZINE

Twilight in the

Rig-Veda

TWILIGHT is a natural phenomenon which is

observable at all places on all parts of the earth. Fora

considerable time after the Sun has set, there exists

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is termed twilight. This is due to the atmosphere

surrounding the earth. It is explained that much dust

and water-vapour are suspended in the atmosphere

and the rays of light from the Sun which pass through

the upper layer of the atmosphere, even after the Sun

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light called twilight. Further this scattered light is

transmitted to other particles further away from

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thus further lengthen the duration of the twilight.

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has entirely disappeared or. at least has become

imperceptible. From numerous observations of the

western scientists, it has been found that the twilight

ends at any place when the Sun is at a vertical depth

of about 18 degrees below the horizon. A similar

phenomenon occurs every day just before the Sun

rises. Here too according to the western astronomers,

the morning twilight starts when the Sun arrives just

18 degrees below the horizon. Thus we have both

morning and evening twilights.

The duration of the twilight is given to be the interval

between the moments when the Sun goes below the

horizon and when all the stars (including the seventh

magnitude stars) of the celestial sphere become

visible, or the interval between the moments when

the seventh magnitude star begins to disappear and

when the Sun comes to the horizon. This duration

of twilight is the least for an equatorial observer on

the equi-noctial clay and is maximum for the same

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on different days of the year. There are certain

places on the earth wherein the twilight continues

throughout the night during certain parts of the year.

There are also certain other/ places situated within the

frigid zone, which enjoy perpetual day and perpetual

night, where there are periods of perpetual twilight

of varying lengths of days. For a north-pole observer,

whose days and nights are six months each, twilight

extends to about 48 days.

In the Yedic literature, Ushas is the name usually

given to the morning twilight and Sandhya for either

of the two twilights. The deity presiding over this

period is the usha devi. She receives great attention

at the hands of the Rig- Vedic Rishis. They describe

the Usha devi as a beautiful, highly ornamented,

young damsel, always marching in advance of the

Sun-god. When describing the evening twilight,

they describe it as a modest young. girl following

her husband’s footsteps. The Ushas or morning

| PROF. R. KRJSHNAMURTHY, M. A.