Re: Possible RQ-180 sighting

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Message posted by Joerg (Webmaster) (Member since 10/17/2000) on October 31, 2021 at 14:26:49 PST:

Thanks Peter! Here is what I did to get the height/altitude equation:

I took a photo of Flat Top (north of Queen City Summit) from my house with the same camera and lens. I then measured the pixel distance in the photos of three different pairs of bushes/trees (each pair several hundred feet apart) on the slope facing my house in the photo. I measured the distance between the same bushes in Google Earth. The vegetation is sparse enough to make it easy to match the bushes. I got an average of 0.295 ft/pixel with minimal variance. I then measured the distance from my house to the slope with the bushes in Google Earth as 69,095ft. Measurements were done point-to-point, not following terrain.

I then measured the wingspan in pixels in the photo. I got 392 pixels in the x-axis and 83 pixels in the y-axis. With the Pythagorean theorem I get a wingspan of 400 pixels.

With those numbers and the rule of proportion I can say:

69,095 ft altitude
----------- = -------------
0.295 ft/px span / 400 px

and finally after rearranging the equation:

altitude = 585.55 * span

If anyone sees any errors in this, please let me know.

In Reply to: Re: Possible RQ-180 sighting posted by Peter Merlin on October 31, 2021 at 14:06:26 PST:


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