Solar elevation angle
To measure the height of the Sun in a certain moment we can use several methods. We go to speak about two basic forms to do it, based in the same principle : determine the height of the Sun from the shadow projected in a surface.
Determination of the height of the Sun from the horizontal shadow projected by a vertical Gnomon
With this method we only have to fix us in the length of the shadow projected by the Gnomon (the Gnomon has to be in a perfectly vertical position). Once we know the length of the shadow and the length of the Gnomon we do not have more than applying a simple mathematical relation to know which height is the Sun over the horizon.
With this method we only have to fix us in the length of the shadow projected by the Gnomon (the Gnomon has to be in a perfectly vertical position). Once we know the length of the shadow and the length of the Gnomon we do not have more than applying a simple mathematical relation to know which height is the Sun over the horizon.
Determination of the height of the Sun using a horizontal quadrant
Another complementary way to know which height is the Sun over the horizon is based in the quadrant and the shadow that projects a perpendicular Gnomon to it.
As wikipedia states, a quadrant is an instrument that is used to measure angles up to 90°. It was originally proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers.
To carry out this measurement we have to ensure that the quadrant is perfectly horizontal. We must to orient it to the South and step by step we must turn it until the shadow of the Gnomon is projected in the quadrant, indicating us in the grid the corresponding angle to which is the Sun over the horizon.
Another complementary way to know which height is the Sun over the horizon is based in the quadrant and the shadow that projects a perpendicular Gnomon to it.
As wikipedia states, a quadrant is an instrument that is used to measure angles up to 90°. It was originally proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers.
To carry out this measurement we have to ensure that the quadrant is perfectly horizontal. We must to orient it to the South and step by step we must turn it until the shadow of the Gnomon is projected in the quadrant, indicating us in the grid the corresponding angle to which is the Sun over the horizon.
Ptolemy's Plinth
Actually the designated as Ptolemy's Plinth is not more than a variant of the previous method. In this case also it uses a graduated quadrant but, unlike the previous case, the quadrant is holding with the hand and his upper edge must to be pointed directly to the Sun.
A rope, string or something similar, of which hangs a weight will indicate us, on the quadrant, what is the Sun elevation angle measured from the horizon.
Actually the designated as Ptolemy's Plinth is not more than a variant of the previous method. In this case also it uses a graduated quadrant but, unlike the previous case, the quadrant is holding with the hand and his upper edge must to be pointed directly to the Sun.
A rope, string or something similar, of which hangs a weight will indicate us, on the quadrant, what is the Sun elevation angle measured from the horizon.
With this instrument it is necessary to have special care to not look directly to the Sun, since it could damage us our eyes.
So, the best thing would be to use alternative methods, like proceeding to project the Sun on a surface, so that we see that the instrument is perfectly oriented.
Another option, for example, would be to use two small additional Gnomon whose shadows, once ranged, would indicate us that the plinth is in the right direction.
So, the best thing would be to use alternative methods, like proceeding to project the Sun on a surface, so that we see that the instrument is perfectly oriented.
Another option, for example, would be to use two small additional Gnomon whose shadows, once ranged, would indicate us that the plinth is in the right direction.
If you want to make a cheap Altitude Measurer why don't you give it a try a these videos ? [ More information, for example, in Hila Inclinometer. ]
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