Kind: captions
Language: en
an astrolabe has many uses
from identifying stars to finding daily
time
it may have been developed by the Greeks
but it reached its Zenith in the hands
of Islamic scientists they wanted to
make better more accurate instruments to
calculate time
this is an Islamic and this instrument
is actually a mechanical computer what
you see here is the projection of the
sky for a specific latitude this is for
Istanbul
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etched on the base plate is the horizon
line
precise altitude circles marking the
sun's height above the Horizon and the
Meridian showing midday and midnight
on top of the base plate is a movable
plate showing stars and constellations
and a ring that represents the apparent
movement of the sun throughout the year
it's labeled with dates
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it starts with one single observation
and we will actually try to maintain the
position of this this piece exactly
aligning with the Sun
I think it's now aligned
this is a perfect alignment
and we just read the the altitude from
here to here it's 54 degrees
that means the sun is 54 degrees above
the Horizon the user now turns the
astrolabe over to find the 54 degree
circle on the bottom plate
Next Step find and mark the date it's
etched on the ring that represents the
sun's path
then rotate the plate until the date
aligns with the altitude mark
if you take a piece of string from the
center of the astrolabe through the
Align points you can read the time from
the rim
the line is like the hand of a clock
it's four minutes past two in the
afternoon
once we reach that we can calculate any
time so that is not as simple to use
instrument but accurate enough for all
time keeping applications
foreign
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