Airliners over Arden: Calibration

HOW HIGH THE MOON CALCULATION

I know something 10 feet wide and 100 feet away measures 2612 pixels across in my camera.

This is the same as saying anything 1 miles wide and 10 miles away would measure 2612 pixels across. Feet or miles, the relationship stays the same.

The moon is 2160 miles wide. Since the relationship stays the same, I know something (1 x 2160) miles wide and (10 x 2160) miles away would measure 2612 pixels. Another way of saying the same thing is this: if the moon were 21,600 miles away, it would measure 2612 pixels.

But it only measures 241 pixels, proportionately further away. It must be (2612 divided by 241) x 21,600 miles away = 234,104 miles away, at least as I measure it with my camera.

How far away is the moon actually? Actually, the distance varies from 225,744 miles to 251,966 miles (363,300 km to 405,500 km), a variance of 11%. (238,855 miles is the average.) My measurement was quite good, though it would be nice to know just how far away the moon was on Wednesday morning, July 7, at 4:00 a.m.

Click here to see a photograph of an airplane overhead.

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