Nix frame 40, the pergola shot.

[Chris Bristow]

The 'vapor trial' in Nix 40 always looked to me like a scratch on the film. There are many previous frames that show similar markings. Like a lot of people I considered the pergola to be too close to Zapruder and never took it seriously. Those are just opinions. But after looking at the necessary trajectory of a shot to Connally it would have to pass through not over the pyrocanthus bush.
 The map on the left verifies the dimensions of the bush by bracketing the Willis 5 bush and the Nix view of it against the background. The West map is very accurate. The purple line from Nix shows Connallys location relative to the background at Nix 40. The thin red line from the pergola to Connally shows the trajectory passing the bush near its center. The overhead map shows the trajectory definitely passes over the bush or through it. The question is over, under or thru? I put the math in the last paragraph.
 
 The photo on the right shows the pergola. The little wall that comes in from the left and stops at the pergola is exactly the height of the pedestal at 430.7 HASL. For the pergola shot to clear the bush and hit JC that 2nd window has to be 78" above the top of that little wall. I have not been to the plaza but have tried to estimate the height of the 2nd window from many photographic angles. The distance from the little wall to the 1st window is maybe 32" to 36". The window may be 12" high and the gap between the windows 8". The rifle would be 3" above the window level so the rifle would be no higher than 60" above the pedestal/wall. but to clear the bush it would have to be closer to 78" above the wall according to the trajectory.
  Shooting under the bush would be a little better but is about 6" off the required trajectory. Nix 40 seems to show the vapor trial going over the bush as it is visible. I assume the theory is it went over not under. The first part of the pergola theory is the head shot came from there. That trajectory would clear the top of the bush. Not saying I endorse it. Unless I am way off on the pergola window height the pergola frame 40 theory does not work. The shot would exit the bush at about the height of the red X I put in the Nix 40 frame.

Determining the slope angle requires two assumptions. For Connally's height I start with the HASL at Nix 40. The survey map shows 418.6 for Z frame 313 and I estimate 318.0 at Connally location. Adding 3.5 ft for JC's entrance wound is, imo,  more than fair and likely too high. 418.0 + 3'6" put him at 421.6 HASL.
 The top of the bush is fairly easy to find because it is right next to the pedestal which is 430.7" per the West map. (The West map also matches google Earth when the 3d building option is off.) Multiple images from that day put the top of the bush at at  29" above the pedestal. The top of the front of the bush is 433 HASL. 
Bush is 433 HASL - JC 421.6 HASL = a rise of 11.6 ft. The dist from JC to the front of the bush is 64ft. That gives a slope angle of 10.3 deg. The important part of that is the slope angle causes the trajectory to increase in altitude by 2.17" per foot traveled. The bush is 23' from the pergola door which means the location of the rifle has to be 49" above the top of the bush to clear it. 2.17 rise per inch x 23ft is 49" of rise. Add that to the 29 " bush height above the pedestal and the rilfe has to be 78" above the pedestal for the shot to work.

Edited December 31, 2022 by Chris Bristow

[Keyvan Shahrdar]

On 5/2/2022 at 12:46 AM, Chris Bristow said:

The 'vapor trial' in Nix 40 always looked to me like a scratch on the film. There are many previous frames that show similar markings. Like a lot of people I considered the pergola to be too close to Zapruder and never took it seriously. Those are just opinions. But after looking at the necessary trajectory of a shot to Connally it would have to pass through not over the pyrocanthus bush.
 The map on the left verifies the dimensions of the bush by bracketing the Willis 5 bush and the Nix view of it against the background. The West map is very accurate. The purple line from Nix shows Connallys location relative to the background at Nix 40. The thin red line from the pergola to Connally shows the trajectory passing the bush near its center. The overhead map shows the trajectory definitely passes over the bush or through it. The question is over, under or thru? I put the math in the last paragraph.
 
 The photo on the right shows the pergola. The little wall that comes in from the left and stops at the pergola is exactly the height of the pedestal at 430.7 HASL. For the pergola shot to clear the bush and hit JC that 2nd window has to be 78" above the top of that little wall. I have not been to the plaza but have tried to estimate the height of the 2nd window from many photographic angles. The distance from the little wall to the 1st window is maybe 32" to 36". The window may be 12" high and the gap between the windows 8". The rifle would be 3" above the window level so the rifle would be no higher than 60" above the pedestal/wall. but to clear the bush it would have to be closer to 78" above the wall according to the trajectory.
  Shooting under the bush would be a little better but is about 6" off the required trajectory. Nix 40 seems to show the vapor trial going over the bush as it is visible. I assume the theory is it went over not under. The first part of the pergola theory is the head shot came from there. That trajectory would clear the top of the bush. Not saying I endorse it. Unless I am way off on the pergola window height the pergola frame 40 theory does not work. The shot would exit the bush at about the height of the red X I put in the Nix 40 frame.

Determining the slope angle requires two assumptions. For Connally's height I start with the HASL at Nix 40. The survey map shows 418.6 for Z frame 313 and I estimate 318.0 at Connally location. Adding 3.5 ft for JC's entrance wound is, imo,  more than fair and likely too high. 418.0 + 3'6" put him at 421.6 HASL.
 The top of the bush is fairly easy to find because it is right next to the pedestal which is 430.7" per the West map. (The West map also matches google Earth when the 3d building option is off.) Multiple images from that day put the top of the bush at at  29" above the pedestal. The top of the front of the bush is 433 HASL. 
Bush is 433 HASL - JC 421.6 HASL = a rise of 11.6 ft. The dist from JC to the front of the bush is 64ft. That gives a slope angle of 10.3 deg. The important part of that is the slope angle causes the trajectory to increase in altitude by 2.17" per foot traveled. The bush is 23' from the pergola door which means the location of the rifle has to be 49" above the top of the bush to clear it. 2.17 rise per inch x 23ft is 49" of rise. Add that to the 29 " bush height above the pedestal and the rilfe has to be 78" above the pedestal for the shot to work.

Hi Chris,

I have to disagree with you here. 

Once you see the vapor trail on the Nix film, you see an immediate reaction downward by JC.

In the Zapruder film zframe 331, JC moves to the middle of the car and gets hit, you see a sharp downward reaction by JC and Zapruder's camera even jiggles at zframe 331. By zframe 336 you can start seeing a discoloration on the back of JC's jacket that was not there before.