It is not necessary to remove your clothes for this assignment.
You are going to build a simple instrument called a sextant, which is used for measuring the elevation of objects in the sky. Elevation is just the angle from the horizon to the object. For example, in San Diego the elevation of the North Star is 32 deg
Go to this link https://solarscience.msfc.nasa.gov/suntime/sxtnt_tchr.pdf (Links to an external site.)
and follow the instructions on the third page. You need a protractor.
The half circle type. You may have a plastic protractor around the
house. If not, you can print out a paper protractor from this link:
The
paper protractor is too flimsy by itself, so glue or tape it to a piece
of cardboard to make it stiff. Cut away the excess cardboard. You are
going to sight along the straight edge of the protractor to aim at the
sun. Ultimatley, I want you to measure the elevation of the sun over
several hours as it gets higher and higher, on its way to local noon..
To get credit, send me a photo of your sextant.
then after you send a picture of it you will use it !!!!!!
Attention,
It’s
time to do something with your sextants. The building of the sextant is
worth ten points. Using it to determine the elevation of the Sun at
local noon will also be worth ten points. The elevation of the Sun is
the angle between the horizon and the Sun.
You will make observations of the Sun over a period of about four hours, from 10 a.m. to 2 pm., on a sunny day.
Sight
along the straight edge of your sextant. Aim the straight edge at the
Sun, just as you would aim the barrel of a gun. The weighted string will
hang against one of the degree markings on the protractor. If you have
an assistant, instruct him/her/it to take note of the degree mark the
string hangs against. If no partner, try to press the string against the
protractor as soon as you have sighted in the Sun, keeping the string
in place, before you lower the sextant. Do this as fast as you can. Do
not stare at the Sun for more than a few seconds. Wear sun glasses if
possible.
The middle of the curved part of the protractor is 90
degrees. Count how many degree markings are between your string and the
90 degree mark on your protractor. That angle is the elevation of the
Sun. The Sun’s elevation reaches a maximum at local noon. So take an
elevation measurement at 10 a.m., one at 10:30, 11:00, etc., every half
hour until 2 pm. You will see the elevation numbers rise to a max, then
decrease again. That max occurs at local noon.
Your measured
elevations should fall in the range of 40 degrees to 70 degrees. I’m
going to measure it too, so don’t just make stuff up. Email me a table
of times and elevations. You must send a photo of your sextant (previous
project) to be elegible for points on this project
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