These
are two circular instruments framed on stone pillars. Both of them are made of seven
alloys, so that different seasons do not affect the readings, and have graduated scales
from 0 degree to 360 degree. The circular instrument has the hole in the middle so that
another instrument could be placed for observations. The metallic instruments are free to
move. When we move these circular instruments, they revolve paralel to earth's axis, and
points towards the pole.
To find the Meridian Pass Time
and declinition of a particular planet, a metallic tube whose extremes are touching the
graduated circle, is placed in the middle hole of the instrument. Through this tube we see
the particular celestial object , and the position on the southern disc will be indicating
Meridian Pass Time. |
