# Calculate the difference in days from one image to

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4. Calculate the difference in days from one image to the next by subtracting the prior day count from the next day count (column 3). 5. Calculate the number of degrees moved from image to image (column 4). Note: The Moon moves in a roughly circular orbit around the Earth. A circle contains 360°. The Moon completes its orbit around the Earth in about 27.3 days. Thus, each day, the Moon moves about 13.2°around the 360° orbit. Multiply (13.2) u(number of days from col. 3) to get degrees moved from prior image. 6. Calculate the number of degrees of longitude for each image (column 5) starting at 270º. Add the degrees moved for the next image (from column 4) to the longitude determined for the prior image. When you reach 360º, start over at 0º. Round to 1 decimal place.7. Plot the Moon’s orbital position on the polar coordinate graph paper given as Figure 2. You will have to plot longitude vs. scale distance, D.On the graph paper, longitude starts at the bottom, labeled 0°, and increases counterclockwise. This will correspond to the true direction of the Moon’s orbital motion as viewed from above the Earth’s north pole.To plot the first data point, place the edge of your millimeter ruler along the line labeled 270° (longitude). Be sure that 0 mm is at the origin of the graph paper, which corresponds to the Earth’s position on this diagram. Now measure out along the 270° line and place a pencil dot at your value of Dfor a longitude of 270°. Continue in this manner for the remaining data in Table 1 (columns 5 and 7). You may have to plot some points in the margin outside of the grid lines. This is OK. When all the data points are plotted, connect the points by drawing a smooth line through them (this is your orbital path). Draw freehand (do not use the compass). 8. If you examine the plotted data on Figure 2, you can see that they are NOTcentered on the Earth. In order to draw the Moon’s orbit, you must first establish the orbit’s center. Open your compass equal to the Davecalculated in step 3. Remember to use the edge of your millimeter ruler to properly set the compass. Locate the center by placing the compass point on four or five (or more)
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