Measuring your Moon images
Now measure the diameter of the Moon in each of your images.
Since you are comparing images, you can use any units you wish — pixels, inches, centimeters, etc. If the Moon is not full, you can measure between any two points that are as far apart as possible—as long as you measure between exactly the same points in both images.
How high above the horizon was the Moon for each image? To find out, use the IMAGE INFO option when you download each image, and record the value for the ALTITUDE. This tells you how far above the horizon, in degrees, the object was when the picture was taken.
TIP: Using a crescent Moon? Then just measure the distance between the two points of the crescent.