The following pdf file contains the IMPACO analysis now housed on the NICAP site:

The major responses to the analysis are provided below:


Date: Sun, 18 Aug 2013 16:00:32 -0400 (EDT)
Subject: Re: [Current Encounters] Latest analysis of McMinnville pictures

I have read their most recent including the string suspension analysis which is quite clever.
Of course I still stand on my original work of many years ago and my "discovery" that
the photo evidence itself could not prove the case because one can always assume
a "perfect" fake. Truth or falsity would then depend upon the witnesses themselves with
the photos only acting as an aid to the memories of the witnesses.

I do commend them for taking the time to do this.  Most skeptics just assume it was a
model or some object (most recently-10 years ago-a truck mirror) and quickly call it
a hoax with no more than a hand wave at the circumstantial evidence that includes the
character/life style of the witnesses.

Regarding the photogrammetric analysis,  I showed that the sighting lines did not
cross under the wires and they did not refute this.  Thus, if a model, the two views of the object
must have resulted from swinging (pendulum motion) and/or moving the suspension along the (lower) wire
between the pictures.

Regarding the photometric analysis (originally done by Hartmann [which Condon attempted to cover up
by saying the photogrammetric analysis was useless] and repeated by me with corrections), they
used measurements from a print to get relative brightnesses. (I used the negatives themselves
with a gamma curve for development of the negatives.)  They used as their basis for "dark" the
relative brightness of the overhead wires.  The roblem with this is that the width of the image of
the wire, unlike the width of the image of the UFO, was not great enough to "overcome" the
brightening effect of the short range veiling glare (which they mentioned) caused by the brightness of
the sky surrounding the wire.  Thus their conclusion that the UFO was no more than
200 ft away is not necessarily correct.  My own conclusion is presented in the
1976 CUFOS symposium paper at my web site.

In their most recent work they are going for the "Holy Grail for skeptics:" finding a string
above the Trent UFO.  They have introduced a new method of analysis for finding suspending
strings (or linear features) in noisy surrounds.  This new method is quite clever and requires
some modern computer power to accomplish (could not have been done 35 years
ago without a large research computer).  Their computer program essentially allows them to
create an average brightness level along any line of image pixels starting at any (lowest) point
and moving along at any constant tilt angle (-30 to   +30 relative to vertical on the picture).  The idea
is that if a thread is darker (or brighter) than the average surrounding (sky) brightness then the average
brightness level along the pixel line that contains the string image will be darker (brighter) than the
average brightness along other lines that start at the same (bottom) point and have different
tilts or that start at other points and have similar or different tilts.
Using this techique they have discovered a line of pixels starting
at the top of the UFO and going upward at an 11 deg slant which is, on the average,
a bit darker than lines of pixels going upwards at other slant angles.  They conclude that
they have discovered "the" suspending thread which was darker than the sky.  They
have found this sort of line of pixels in prints TRNT1 and 2  but not in a second
set of prints.
Is this convincing?  It could be if they could show that the "string line" is unique in the
sense that they don't get the same sort of result if they start the analysis at any other
point in the picture and scan the tilt over the same range of angles.
If this "dark line" is unique yet there is no string (not a hoax) one would have to ask
how such a line got there in both prints.
One should also ask whether or not it makes sense for the string to be tilted about
11 deg in each picture.  We the supposed model swinging left and right as it
also moved forward (toward the camera) and back?


From: Brad Sparks
Date: Mon, 19 Aug 2013 06:56:32 -0400 (EDT)

The IPACO Debunkers Attack the Trent Photos (McMinnville, Oregon, May 11, 1950)
The IPACO team has jerry-rigged its case and cherry-picked its figures to coincide with its convenient but grossly contradictory hoax model.  Contradictory modeling is IPACO's number one fault violating the laws of physics, optics and geometry -- and they do claim to use "mathematics and physics" (p. 3).  They have thrown together so many simplistic "simplifications" (p. 11) or bald assumptions to streamline and "clarify" the case that their patchwork of questionable parameters hide gross errors.  They conveniently assert that these self-serving simplifications "do not impact significantly upon the results" (p. 11).

This points up the fundamental error in their overall methodology:  Instead of creating a comprehensive and integrated computer 3-D reconstruction model of the Trent backyard site and postulated objects where every adjustment of a parameter is automatically adjusted throughout the reconstruction, they have created a patch-work "tool" that allows gross errors to creep in and get taken advantage of in order to debunk the UFO case.

For those needing a refresher on the famous McMinnville photo case read my summary below, or else skip to the next section.

CASE SUMMARY (from BB Unknowns Catalog)  May 11, 1950.  8 miles SW of McMinnville, Oregon (UFO at 45.1043° N, 123.3335° W).  7:20 p.m. (PST).  Evelyn Trent was feeding the rabbits in her backyard just before sunset when she spotted an object to the N in the distance and called out to her husband Paul Trent, who was in the house at the back door, asking him to retrieve their camera.  She went into the garage to look for the camera but Paul found it in the house, ran out into the yard toward where his wife had been standing, then he saw the rapidly approaching large metallic object to the N heading almost directly towards them, “tipped up” its flat underside towards them, felt a gust of wind seemingly from the object, snapped a photo of the object at azimuth 335° (about NNW) elevation 14°, angular size 1.67°.  Paul Trent was at 45.1007° N, 123.3335° W, in his back yard between the house and garage.  Then as the object turned on a W heading he walked 5 ft to his right to compensate for object's motion to the left, snapped a 2nd photo about 30 secs after the 1st, which shows a metallic pie-pan shaped object 1.46° angular size with a large off-center tilted antenna or pole projecting from the top, at azimuth ~317.5° (about NW) 12° elevation.  Evelyn had joined Paul by the time he started taking pictures and later described the arc covered between photos as about 15° (close to actual figure ~17.5°).  Distance and size of object estimated by the witnesses as about 1/4 mile distance and 20-30 ft diameter, or "parachute-sized" (about 24-28 ft), which size/distance figures translate to a maximum angular size 1.3° (close to the photographically measured 1.46°-1.67°).  AF Colorado Project and Bruce Maccabee estimated distance about 1 mile and object diameter about 100 ft but methodology is mistakenly based on excess brightness of what was supposed to be dark shadow of the bottom of the object (in fact the bottom was not in shadow but caught bright near-sun sunset sky illumination at near grazing angle 2° off of direct sunlight).  Several other witnesses reportedly saw the object.  (Sparks;  Condon Report pp. 396-407;  Bruce Maccabee;  Hynek UFO Rpt pp. 244-5;  etc.)   Duration 2-3 mins

The Fatal Flaw -- The Dilemma of the 5-inch Hoax Model versus the 6-inch Model

The IPACO debunkers never consistently follow through on a numerical result throughout the rest of their analysis to see if it fits and is physically consistent.  They cannot make up their collective minds whether the UFO hoax model is 0.4 ft or 0.5 ft (about 5 inches or 6 inches).  It cannot be both!  It is a crucially important parameter and it is based on the most accurately determined parameters in all of the two photos, namely the angular diameters of the UFO's base (1.67° and 1.46° in Photos 1 and 2, respectively).  If the hoax object was 5 inches in diameter then the closest distance to camera, which is in Photo 1, must be about 14 ft according to the geometry of the angular size (angular size is roughly the size-to-distance ratio).  This is mathematically locked and cannot be fudged or adjusted or obscured -- as IPACO attempts to do.  (I will call these debunkers collectively as "IPACO," and in the singular or the plural regardless of grammar, for ease of reference.)

TECH NOTE:  Angular size is approximately the size to distance ratio, as I mentioned above.  That means the object -- no matter what it is whether a pie tin, a UFO or a planet in space -- must exactly fit mathematical laws of geometry.  If it is 1.67° is angular size then it must be exactly 34.3 times farther away than its size (1 / [2 tan 1.67°/2]).(to the three-digit precision I am using).  If it is 1 ft in size then it must be exactly 34.3 feet in distance.  If 1/2 foot in size then its distance must be ~17.15 feet.  These are exact mathematical rules and cannot be broken at the whim of those who find it inconvenient.  Similarly, in Photo 2 the angular size is 1.46° and hence the distance must be 39.2 times its size.  If 1/2 foot in size then the distance must be exactly 19.6 feet.

Since the wire that IPACO claims the hoax object was hung from (by a thread) was about 14 feet from Trent's camera (p. 9) the 14-foot distance set by the 5-inch diameter of the hoax model would seem to fit just about perfectly.  So why do they bother to keep bringing up the 0.5 ft (6-inch) figure for the UFO hoax object when that would result in distances of about 17 feet and 20 feet?

The reason is that the UFO increases distance from the first to the second photo by a very exactly determined amount of about 14%, established mathematically by the object becoming smaller in apparent (angular) size.  IPACO points out that that would mean the hoax model had to increase in distance 2 ft, going from 14 ft (where the wire was located) to a distance of 16 ft in the second photo.  But the height of the wire above the object, and thus the approximate length of the alleged suspension thread, is only about 2 feet.

This 2 foot distance increase is about the same as the purported length of the 2 ft pendulum thread!   If the alleged hoax model was "swaying" on a pendulum thread it would have to swing so violently that the model would be suspended horizontally and away from Trent's camera in Photo 2.  Imagine if you were swinging in a children's swing and you managed to get as high as the bar holding up the swing!  It would be very unstable from a dynamic physics standpoint and a geometrically impossible position because the UFO model would also be about 2 feet higher above the ground too and it is manifestly not.  (The angular space between the UFO and the wire above, which are supposed to be about the length of the suspension thread, are about 9° to 8° in the two photos but this 2 foot swing away would reduce the spacing to about 0° in the second pic and it obviously is not!  See IPACO p. 8 for diagrams and angular figures.)

This is why IPACO fudges the numbers throughout by injecting the 6-inch hoax object diameter where it does not belong, since it increases the scale of dimensions and thus the length of the suspension thread to almost 3 feet.  A 2 ft swing backwards on a 3 ft long thread is not so enormous and violent.  IPACO insists throughout that there was only gentle "swaying" of the hoax object in a "light wind."
But IPACO can't have it both ways!  The UFO model can't be 5 inches in diameter for some situations and 6 inches for others!

So why doesn't IPACO just stick with a 6-inch diameter for the UFO model and use that throughout?  Because it would run into the same problem of a 3-foot thread swinging backwards by about 3 feet and worst of all, it would be 3 to 6 feet away from the wire it is supposed to be hanging from!  (The wire at about 14 feet and the 6-inch object at about 17-20 feet.)  Obviously it cannot possibly be 6 feet away while connected with a 3-foot thread!  Maybe the hoax model was capable of sustained flight -- like a UFO!

So why doesn't IPACO get rid of the 6-inch diameter figure altogether?  Because they need to slip it in whenever there is a problem with the 5-inch model swinging too wide and high, and they just obfuscate the more severe problems with the 6-inch model by not running through all the logical consequences of that bigger size.

Here is a classic example of IPACO obfuscation where they mix inconsistent numbers from the 5-inch model with the numbers from the 6-inch model in their General Conclusions:

Revised IPACO Report, June 2013 (released Aug 2013, p. 23, emphasis added):

"Explanation 1
"The UFO is a model hanging ca. 3 ft under the lower power wire, at a distance of ca. 14 ft from the camera.
"Its size (diameter of its circular base) is ca. 0.5 ft.....
"Between both shots, its distance from the camera increases by 2 ft."
The 3 ft and 0.5 ft (6-inch) figures belong to the 6 inch model's parameters, of course.  The 14 ft and 2 ft figures only apply to the 5-inch diameter object.  IPACO has slyly mixed inconsistent numbers from two different scenarios and size scales.

TECH NOTE:  If as stated it was really a 6-inch diameter (0.5 ft), then the distances from camera would be 17 to 20 ft not 14 feet and the increase in distance (from 17 to 20 ft) would of course be 3 ft not 2 ft.  (20 - 17 = 3 ft.)

IPACO is caught on the horns of a dilemma.  A 5-inch would have to swing up too high and too violently and it simply is not seen in that position in the photographs.  A 6-inch model would be much too far away, so far away that it would not even be connected to the thread!

Could the violent swing be reduced to more manageable and viable proportions by splitting the total swing between a swing towards the camera in Photo 1 and a swing away in Photo 2 -- as IPACO seems to obscurely be reaching for at one point in their almost unintelligible discourse (p. 11)?  No, because the 5-inch model would be at about the same distance as the overhead wire, 14 ft, in Photo 1, and thus hanging directly below the wire not swung towards the camera.

IPACO Claims to Discover a "Thread" in the McMinnville Photos -- But it would be Nearly 1 Inch Thick!

The IPACO debunkers claim to have discovered something -- a purported thread above the UFO -- that no one else has been able to see in 63 years, including high-tech image processing by the Jet Propulsion Lab director Robert Nathan, by Bruce Maccabee and others, that never found a thing.  Naturally, IPACO did not conduct a control study to see if this was just noise in the film or photoanalysis.  They checked only 60° or 1/6th of a full 360° circle.  They did not check underneath the UFO -- because obviously they know it's a hoax and so it cannot be something absurd like a thread below the object.  But that's how one makes scientific checks.  If an absurd result emerges then it tells you the analysis is wrong.  I can already see other "threads" in their data, which would make nonsense of their findings.

But worst of all, the purported IPACO "thread" -- which cannot be seen visually -- would be almost 1 inch in thickness (using the half-value width as a rough thread width; it is about 0.2° in angular width or about 1/7 or 1/8 of the width of the supposedly 5 or 6-inch object).  What kind of "thread" is that and why wouldn't a 1-inch thick line -- more like a rope or heavy cord -- not be painfully obvious in the photos?

Another Typical Example of Error in IPACO Assumptions -- The Two Power Wires are Not Vertically Stacked

IPACO's assumptions from the very start are in error.  Early in their report they say:

Revised IPACO Report, June 2013 (released Aug 2013, p. 5, emphasis added except bold-only is in original):

"In the first steps of the analysis, we concentrated on the following elements of the scene:
 The UFO, localized in space by the center of its base, which is assumed to be nearly circular (seen as nearly an ellipse from the camera),
 The two power wires above the UFO, assumed to be motionless.
"It was possible to check, from the already mentioned detailed map of the site established by Maccabee, and from a picture published in Condon report’s Plate 25 (Hartmann 1967), that these two power wires were one above the other (i.e. in the same vertical plane). Therefore, if the UFO is effectively a model, it should logically be hanging from the lower power wire."

The two wires in fact are not vertical except at the back of the house.  LIFE magazine photographer Loomis Dean visited the Trents and took dozens of photos in mid-June 1950.  Dean's photos show that the two wires twist in the air gradually to attach almost horizontally (not vertically) to the roof edge of the garage at the south end.  The lower wire is attached about a foot down and east from the peak of the garage roof where the top wire is attached.  That means that in the middle of the gap between the house and the garage the wires are not situated directly above each other in a "vertical plane" but are rotated and offset by roughly 30° from vertical.  That makes the lower wire closer to the camera and still more distant from the sighting line crossing point, and thus makes a hoax model even more difficult.  You can even see in Condon project astronomer William Hartmann's photo of the backyard that the two wires immediately narrow as you follow them from the house into the space to the garage, which space is where the UFO was photographed.

Debunker "Science" -- Confusing Thermal Physics with Optical Physics

These French debunkers have incomprehensibly asserted that the UFO and wires are "black bodies" to which they apply "radiometry" -- which is the science of measurement of heat.  They claim to derive an estimate of distance from this.  They apparently have no idea what they are talking about.  Yeah, the Trent farm and nearby objects are "black bodies" but at around room temperature emitting heat in the far infrared (about 9,000 nm) invisible to the eye and invisible to the ordinary camera and thus unseen on visible-light optical photographs (visible light is about 300 to 700 nm wavelength).  Visible light "radiometry" would be at about the temperature of the sun ~ 5,000° C and a camera is not a radiometer!  They have confused photometry (light measurements) with radiometry (heat measurements from black body heat radiation, thermal emissions).

But this goes far beyond a simple confusion of terminology since they repeatedly invoke "black body" radiation (p. 17; see original IPACO March 2013 report, pp. 19, 23 "behaved approximately like a black body," etc.) as somehow involved in reflection and absorption of light (not infrared) at roughly room temperatures and that they are able to determine "distances from the camera" because, you see, "a lower radiometry roughly corresponds to a lower distance from the camera" (p. 17)!!!  No it doesn't!

Revised IPACO Report, June 2013 (released Aug 2013, emphasis added):

"If we assume that these elements are dark enough to be considered as sort of “black bodies” (i.e absorbing all the light they receive), we may compare their respective radiometric levels and infer a classification of their respective distances from the camera: a lower radiometry roughly corresponds to a lower distance from the camera.

This must be on the order of saying "if I like the object it must be closer to me and the more I like it, the closer it is!!"  ROTFL.  (Normally if there is a lower radiometric power received from an object -- less heat radiation -- it indicates a greater distance not a "lower distance," but hey this is trying to make some sense out of nonsense, to extract the science from pseudoscience.)

IPACO's "physics" is very much like that of William Spaulding who used to announce that he could determine the "thickness" in feet or inches of the UFO in a photograph, using "computer analysis."  He confused x-rays with visible light photos.  X-rays are beamed through objects and can be used to determine the linear thickness of an object, in feet or meters.  But visible light photos involve light reflecting or scattering off the surface and thus cannot possibly determine the thickness of the object below the surface.

Remember, IFO's must obey the laws of physics.  Unfortunately, debunkers don't care about whether their hoax or IFO scenarios grossly violate the laws of physics -- that's a problem for someone else to solve, if anyone still cares after they succeed in destroying the hated UFO case.

Brad Sparks