Observing the Change in the Moon’s Position and Appearance using Horizontal and Vertical Angular Measurements

The aim of this activity is to observe the change in the moon’s position and appearance using horizontal and vertical angular measurements over a period of three consecutive nights from a fixed reference point during the same time of the day.

b)    Location and description of reference point

The selected area for this activity was an open community playground. The exact area of reference for the activity was at a distinctly raised rock formation at the center of the playground which I marked using a marker pen. The vertical angle measurement reference object for the task was a raised flagpole on the far end of the open playground. The horizontal angle measurement object was the visible horizon.

c)    Observation

During the first day of observation, 29/1/2018, at 6:30 PM, the horizontal angular measurement in relation to the pole is 100, and vertical angular measurement in relation to the horizon is 480. The appearance of the moon is grey in color, humpbacked and not fully illuminated, the moon is. However, more than 75% illuminated and appearing slightly similar to a full moon.

During the second day of observation, 30/1/2018, at 6: 30 PM, the position of the moon had changed from the previous day position; the horizontal angular measurement had increased from 100 to 230 towards the East in relation to the reference point, the pole. The vertical angular measurement in relation to the horizon also increased slightly from 480 to 530. The illumination of the moon had also increased with more parts of the moon is clearly illuminated.

During the third day of observation, 31/1/2018, at 6:30 PM the position of the moon had further changed from the previous day observation. The horizontal angular measurement increased from 230 to 360 from the reference point, the pole. The vertical angle slightly changed from 530 to 600. The moon appeared full as the illumination had further increased from the previous illumination. It is also worth noting that the color of the moon had slightly changed, the moon appeared slightly blue in color away from the normal grey color.

d)    Activity Questions

i) During the three day observation, the appearance of the moon changed slightly. The illumination of the moon increased gradually, and on the final day, most parts of the moon appeared illuminated as it approached the full moon. On the final day of observation, the color of the moon also changed slightly, appearing as a blue moon.

ii) The position of the moon also changed during the observations with the horizontal position changing significantly. The moon moved towards the east in notable angles, the overall change in the horizontal angle within two days was 260. The vertical position of the moon also increased.

iii) Using the data obtained from the activity, the change in the position of the moon is about 260 in two days, and therefore the horizontal average angular difference in the position of the moon is 130 per day. The vertical angle difference is 50 per day.