posted 03-24-2001 03:10 PM            

Rather than drifting apart in our respective opinions, it seems to me we have come to a common denominator....that these trails were most probably laid by military aircraft performing maneuvers. Now does this definitively rule out the possibility of spraying? Well, I think if anything, it may enhance that possibility because military aircraft (or aircraft that contract with the military) are what we would expect to be the culprit of chemtrails. But before we consider the unknown or more anomalous explanations like aerial spraying, I think it is important to consider the known first....and rule those out. Like I said, I think we may have ruled out the possibility of holding patterns by simple deductive reasoning...but have we really ruled out “Top Gun’s” explanation? Do we know for sure the altitude of these trails and the relative humidity and temperature that would rule out the possibility of normal contrail formation? Off hand, I would say that based on the information presented, there is no way to “ball park” the altitude. As we have shown, we do not have the trigonometric information available to guestimate altitude (for that we need at least one angle and side of a right triangle).....nor do we have radiosonde information for the day in question regarding temps and humidity aloft to prove that normal contrail formations at that altitude was not possible.

Without this relevant information....it becomes impossible to rule out “Top Gun’s” explanation. By the same token, it also becomes impossible to rule out the possibility of chemical spraying. Both scenarios could likely happen in an MOA (Military Operations Area).

posted 03-24-2001 03:31 PM            

Pilots of low performance aircraft generally use an E6B computer or electronic version to make calculations when equipment on board the aircraft is minimal and not very sophisticated. Manual trigonometric calculations are rarely required nowdays with more sophisticated equipment on board like GPS, INS (inertial navigation systems) and flight computers that take into account, wind direction, crosswind component, aircraft airspeed and fuel requirements at the pressure altitude to be flown converted to true altitude and airspeed for groundspeed and range estimation. There are also graphs in the pilot's operating handbook to accurately arrive at this information based on aircraft performance, range and fuel consumption at altitude.

Dirk was absolutely correct, by the way, as you keep failing to acknowledge...and this was an application of trigonometry that is not generally used by pilots.....but rather, more often used by surveyors with special equipment with laser range finders to find angles and accurate range.

posted 03-24-2001 03:43 PM            

could you please tell me the straight line distance from the camera to the point on the earth directly below the trail?

by the way, thanks for the suggestion about taking more trig classes, but i think i'm alright.

posted 03-24-2001 04:17 PM            

http://www.ballparks.com/baseball/general/ads/ad061.htm

in this photo there is a cloud layer above the apartment buildings on the right side of the photo. now, the apartment buildings are 200 ft tall. they are 10000 ft from the camera ( i know this because i grew up at wrigley field)

using these figures please tell me the height of the clowds.

posted 03-25-2001 04:33 PM            

did you have a chance to "do the math", as you instructed me, on my above photo.

posted 03-25-2001 05:08 PM            

ok Mark, here is another one for you.

this page has 9 pics on it. the pic all the way on the bottom and to the right shows the front of a terminal building with an ominous looking trail above the terminal. notice that the trail comes down and "touches" the terminal just as your trail "touches" the hill. so, very similar picture to your so you should be able to use the same formulas to determine the height.

here we go.

the camera is 50 ft in front of the terminal.
the terminal is 35 ft high.
what is the height of the trails?

posted 03-25-2001 06:00 PM            

3T3,

posted 03-25-2001 07:40 PM            

Now if marksky has a way to do this, then I think it would be highly useful information, so we can get a quick and dirty estimate for contrail altitude in the future.

posted 03-25-2001 08:51 PM            

"we can judge our distances and trust our powers of observation"

the point i am making is that you can not judge these distances with any sort of accuracy. this is not a slight towards you, i can not either. it is hard for me tell from the ground if an airliner is at 25,000 ft or 35,000 ft

mark sky has a picture that he claims is of low-level spraying. i believe he is mistaken. if you take that photo to "60 minutes" it will quickly be disregarded. i was trying to point this out by giving an almost identical math problem. i think if you look at it closely then you will see my point that you can not compute the height of his trail based on a hill that is in between the camera and the trail.

posted 03-25-2001 09:13 PM            

First assumption--the camera is being held five feet above the ground, so the top of the terminal is 30 feet higher than the camera lens.

Second assumption--that the contrail has formed at 35,000 feet. Top Gun says he has trailed at 20,000 feet, but we'll assume Mark's height for contrail formation is correct in this instance. The height of the camera and the height of the terminal above sea level are small fractions of 35,000 feet, so we shall ignore them. We shall also assume that the earth is flat. :-)

Visualize a right triangle. The camera is located at one of the acute angles. Call the "opposite" side of the triangle 35 feet minus 5 feet, or 30 feet long. The "adjacent" side of the triangle runs parallel to the ground, from the building to the position of the camera, and it is 50 feet long.

Visualize another, bigger, right triangle laid over the first one. The "opposite" side goes from the contrail to the ground, so it is 35,000 feet long. The "adjacent" side runs from the right angle to the position of the camera, parallel to the ground, and we'll call it "x" feet long.

Because the top of the building and the contrail overlap from the perspective of the camera, the angle where the camera is located is the same in both triangles. This makes them "similar" triangles.

posted 03-25-2001 09:41 PM            

you just proved my point. you said "Second assumption--that the contrail has formed at 35,000 feet. "

we are trying to find the height of the contrail. the contrail is the unknown. your formulas are correct but you are not using them correctly.

use the same formulas and find THE HEIGHT OF THE CONTRAIL. dont assume anything about the contrail.

in mark sky's famous "hill and low chemtrail" photo he used the known constants (distance to hill and height of hill) to determine the height of the trail. i am asking you to do the same thing with my photo. i have given you the same knowns (distance to building, height of buliling) that mark sky has given you. so you should be able to determine the height of the trail. you shouldnt have to assume antyhing. mark sky didnt assume anything.

posted 03-25-2001 09:45 PM            

I think I see what you're saying 3T3, (drew it out on paper to get the visual). But the problem with this equation is that you are still assuming facts not in evidence.

For example, you assume the height of the contrail...but this is the very thing that the equation attempts to find out!.

Now, we can divide 30 by 50 and take the inverse tangent to get the angle, but we still don't know the distance of the adjacent side of the larger right triangle to a point directly beneath the trail....and we still don't know the height of the contrail from a point directly underneath it.

posted 03-25-2001 11:38 PM            

"For these trails to be at 35000 feet elevation, they would have to be 50 to 60 miles in the distance."

What he's saying is that there is a restricted range of altitudes at which true contrails can form. He has taken 35,000 feet as a reasonable average. If you take the values at either end of the permitted range, you come up with a range of distances at which true contrails would be located. He's saying that, if these are true contrails, they must be about 50 miles away from his camera. He doubts that he would have seen that much clarity and definition in the trails if they really had been that far away.

posted 03-26-2001 01:03 AM            

remember also, that the part of the trail that "has to be 60 miles away" is almost to the horizon (the part that touches the hill).
very possible.

"they must be about 50 miles away from his camera. He doubts that he would have seen that much clarity and definition in the trails"

to give you an example. i do a lot of GA flying on the east coast of florida. on a good day you can see all the way to the other side of FLA. and this is at a relatively low altitude. this distance is roughly 110 nautical miles.