Hello!
On this equinox, i.e.on 23rd September, I have for the first time calculated the latitude of my location, Hyderabad, India. The trick is simple, at the time of the local noon mark the tip of the gnomon's shadow. For this you have to set your watch accurately to the GMT based time and add your local time difference to that.
Then measure the length of the shadow as well as that of the gnomon. All that you need to find is the angle made by the Sun. On the equinox day the angle made by the Sun is nothing but the latitude of the location.
To know the angle, just divide the length of the shadow by the length of the gnomon and inverse it with the angle of tangents. You get your latitude.
And how you find your longitude?
You can conduct the experiment in India to find out longitude using Gnomon on any of the following 4 dates in a year: Apr 16, Jun 14, Sept 02, Dec 25. You will need a watch set to correct and the Shortest shadow experiment setup. Just conduct the shortest shadow experiment at noon and note the time of the shortest shadow, this is the time of your local noon as well.
- On the above 4 dates, the local noon happens exactly at 12:00 noon at
the 82.5° E longitude.
- If your local noon happens after 12:00 noon, you are further east of
82.5, else you are west.
- Now simply divide the difference (in minutes) between your local noon
and 82.5 (which is 12:00 noon) by 4. You will get the difference in
longitudes.
- Subtract the difference in longitude from 82.5 if you are west. Add if
you are east.
On this equinox, i.e.on 23rd September, I have for the first time calculated the latitude of my location, Hyderabad, India. The trick is simple, at the time of the local noon mark the tip of the gnomon's shadow. For this you have to set your watch accurately to the GMT based time and add your local time difference to that.
Then measure the length of the shadow as well as that of the gnomon. All that you need to find is the angle made by the Sun. On the equinox day the angle made by the Sun is nothing but the latitude of the location.
To know the angle, just divide the length of the shadow by the length of the gnomon and inverse it with the angle of tangents. You get your latitude.
And how you find your longitude?
You can conduct the experiment in India to find out longitude using Gnomon on any of the following 4 dates in a year: Apr 16, Jun 14, Sept 02, Dec 25. You will need a watch set to correct and the Shortest shadow experiment setup. Just conduct the shortest shadow experiment at noon and note the time of the shortest shadow, this is the time of your local noon as well.
- On the above 4 dates, the local noon happens exactly at 12:00 noon at
the 82.5° E longitude.
- If your local noon happens after 12:00 noon, you are further east of
82.5, else you are west.
- Now simply divide the difference (in minutes) between your local noon
and 82.5 (which is 12:00 noon) by 4. You will get the difference in
longitudes.
- Subtract the difference in longitude from 82.5 if you are west. Add if
you are east.
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