Gnomon - To observe Moon.

Gnomon - To observe Moon.

Dear ***,
Assalamu alaikum WR WB. ;

The Gnomon at the Moideen palli at the southern end of Kalpeni island in the Lakshadweep Island was first noticed by me when I visited in 1990 with Dr. Lotika Varadarajan. A historian of Jawaharlaal Nehru University in Delhi. It is about 5 centuries old and no one knew why it was built. A very old man told us that it was made by an Usthad long long ago for observing the crescents of the moon. Later in 2011, I visited the Island and studied how it could be used for moon observation.
gnomon which was used to know the meridian passage of the moon in those days

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The Gnomon is a rectangular pillar about 5 feet high. The sides of pillar are exactly facing 4 directions North. South, West and East. A rectangular pedestal is built on the North side so that the observer can sit on it facing south for observing the last crescent on the 7th day.
The observer views the moon overhead comparing with the tapering point of the pillar. The crescent will be declining towards the west on 7th and declining towards east on 8th from the central point of the pillar.
On the full moon night the moon will be on meridian at midnight.
At the observation time, sun rise or sun set, the moon cannot cast a shadow. So direct observation is necessary.

The first of the month could be known by observing on 24th or 25th. This observation is carried out just before sun rise. Such methods were in Kerala also about hundred years ago.
Modern instruments such as watches have replaced the old methods. Now the children cannot calculate without a calculator.

Wassalam.

Ali Manikfan