Something that always struck me as odd was the insistence of some UFO enthusiasts like Dave Falch and Marik von Rennenkampff that there was a limit on how far a FLIR camera (like an ATFLIR or a Wescam MX, or a FLIR Safire) could see a plane. I've seen specifications that give limits, but they seem to be for the laser rangefinder or target designator. Being able to see and record the heat of a plane's engine seems no harder than seeing any distant object.
This argument crops up in cases like Gimbal, where there's a plausible path of a plane about 30-35 NM from the camera, and Chilean Navy, where there's a plane visible 90 NM away. Falch claims neither are possible. Marik recognized Chile is a plane, but claims it's due to exceptionally dry air (despite there being clouds and contrails, which would actually indicate relatively humid air)
A simple counterexample is to point out that you can see the Moon. Here, for example, is the Moon videoed with a Wescam MX-20
And here it's with an ATFLIR:
We see here the videos are in WHT - White Hot. The Moon, when warmed by the sun is quite hot. So we are seeing heat from thousands of miles away.
Now the argument for distance limits seems to be atmospheric extinction - where the air blocks or scatters heat (or light), meaning you can't see that far. The Moon shots might be looking straight up, so through not that much atmopshere?
But no. The ATFLIR image is pointing up just 6°.
The Wescame imag has an elevation (upwards tilt) of 08, which I think actually should mean 80°, so is this super clear image pointing nearly straight up? No, the angle here is actually more shallow than the ATFLIR example. We can see this if we enter in the date, time, and location and look at the moon. The elevation angle is just under 2°.
https://www.metabunk.org/sitrec/?cu...amazonaws.com/1/MX_20 Moon/20250701_044614.js
But the Moon is very big. Is there something that stops us from seeing planes, which would be much smaller at a distance?
There actually seems to be a plane, which might help answer the question
It seems to be a plane because it's flying horizontally and leaving a contrail. We can also tell it's very far away. How far? The Moon, was we know, subtended about 0.5° on screen. The Moon at the start of the video is 475 pixels across. The blob (the heat signature of the distant plane) is just 3 pixels across, so it's 0.5 * 3/475 = 0.00315° long on screen.
If we take the most likely type of plane, a cruising 737, then to match the video, we have to place it 130 miles away, and to be at a reasonable speed, it would be flying away from the camera (so hot parts facing the camera)
(notice also here, the motion of the Moon itself is the same in video and sim, one more confirmation that it's correct).
A large plane would mean a greater distance. We could put in a smaller plane and pull it closer, but we also know it's at contrail altitude, so at least 25,000 feet. Pulling it back to an F/A-18 30 miles away gives us something at 7,000 feet. To get something reasonble with an F/A-18 at 25,000 feet, it has to be 95 miles away.
But it's white hot! So why would a plane be black (cold)? It's actually grey. But that still seems to indicate it's not that hot. Are we seeing a diluted mix of the plane body and exhaust? Or is this actually something else?
This argument crops up in cases like Gimbal, where there's a plausible path of a plane about 30-35 NM from the camera, and Chilean Navy, where there's a plane visible 90 NM away. Falch claims neither are possible. Marik recognized Chile is a plane, but claims it's due to exceptionally dry air (despite there being clouds and contrails, which would actually indicate relatively humid air)
A simple counterexample is to point out that you can see the Moon. Here, for example, is the Moon videoed with a Wescam MX-20
And here it's with an ATFLIR:
We see here the videos are in WHT - White Hot. The Moon, when warmed by the sun is quite hot. So we are seeing heat from thousands of miles away.
Now the argument for distance limits seems to be atmospheric extinction - where the air blocks or scatters heat (or light), meaning you can't see that far. The Moon shots might be looking straight up, so through not that much atmopshere?
But no. The ATFLIR image is pointing up just 6°.
The Wescame imag has an elevation (upwards tilt) of 08, which I think actually should mean 80°, so is this super clear image pointing nearly straight up? No, the angle here is actually more shallow than the ATFLIR example. We can see this if we enter in the date, time, and location and look at the moon. The elevation angle is just under 2°.
https://www.metabunk.org/sitrec/?cu...amazonaws.com/1/MX_20 Moon/20250701_044614.js
But the Moon is very big. Is there something that stops us from seeing planes, which would be much smaller at a distance?
There actually seems to be a plane, which might help answer the question
It seems to be a plane because it's flying horizontally and leaving a contrail. We can also tell it's very far away. How far? The Moon, was we know, subtended about 0.5° on screen. The Moon at the start of the video is 475 pixels across. The blob (the heat signature of the distant plane) is just 3 pixels across, so it's 0.5 * 3/475 = 0.00315° long on screen.
If we take the most likely type of plane, a cruising 737, then to match the video, we have to place it 130 miles away, and to be at a reasonable speed, it would be flying away from the camera (so hot parts facing the camera)
(notice also here, the motion of the Moon itself is the same in video and sim, one more confirmation that it's correct).
A large plane would mean a greater distance. We could put in a smaller plane and pull it closer, but we also know it's at contrail altitude, so at least 25,000 feet. Pulling it back to an F/A-18 30 miles away gives us something at 7,000 feet. To get something reasonble with an F/A-18 at 25,000 feet, it has to be 95 miles away.
But it's white hot! So why would a plane be black (cold)? It's actually grey. But that still seems to indicate it's not that hot. Are we seeing a diluted mix of the plane body and exhaust? Or is this actually something else?
