1994 Nellis / Tonopah Test Range UFO (Sightings / Hard Copy)

[LorentzHall]

Apologies if this has been posted before. I searched with every possible term but couldn't find it.

Amateur astronomer Martin J Powell's website contains a detailed, thorough analysis of a seemingly-peculiar unidentified flying object tracked at the Nellis Test Range in 1994.

Part 1: Location
https://www.aenigmatis.com/nellis-ufo-video/part-one/nellis-1.htm

In February 1995 the American TV show 'Hard Copy' broadcast a videotape showing an unidentified object flying over a North American military test range. Further footage was shown the following December on the 'Sightings' TV show. The videotape had apparently been filmed by a high-tech Air Force surveillance camera at an undisclosed location within the Nellis Air Force Base Bombing and Gunnery Range Complex, Nevada (often referred to simply as the Nellis Test Range).

The videotape is said to have been smuggled out by contractor personnel who had operated tracking stations on the Nellis range. Copies of the videotape were sold to Paramount Studios (producers of 'Hard Copy' and 'Sightings') by a former Air Force employee who worked on the range, although apparently he had not witnessed the object himself.

Figure 1 The Nellis UFO, shown in two different views from the S-30 footage.

Two sections of videotape showing the UFO have come to light. The first section was filmed from a location known as S-30, according to the camera's data display. This shows the object initially as an indistinct 'blob' flying in front of a distant mountain range, before it turns and heads towards the camera location. The camera operator struggles to keep the object within shot as it approaches, and it soon becomes clear that it cannot be identified. It looks similar to a blimp, but with four light-coloured 'lobes' and a dark region at the front. As it nears, it turns to face the tracking station for several seconds, as if performing some kind of surveillance, before it turns away and departs. The footage is of special importance because the voices of the camera operators at the tracking station can be heard on the noisy soundtrack. Their bewilderment at the unexpected appearance of the UFO is clearly audible. "What the hell is it?" one of them exclaims; "Where's it come from?" asks another.

Figure 2 The tracking camera display as it appears in the S-30 footage. The S-13 display is similar, but with the additional letters 'CG' and 'LAU' at the lower part of the screen.

The second section of footage was filmed some 40 minutes later, from camera location S-13. This shows the UFO as a small dot on the horizon, moving away from the tracking camera. Although it has less visual impact, the soundtrack to this section is important because the controllers are heard to simulate a missile launch on the object. It remains visible, however, eventually disappearing into the realm of mystery and speculation that surrounds the Nellis Range.

Figure 3 (Top) Black Mountain, Nevada, as it appears from tracking station S-30, in the early part of the Nellis UFO footage (click on image to enlarge). This image is a montage of numerous screen shots taken over a period of about half a minute. (Bottom) The author's computer-generated profile of Black Mountain, as it would appear from a location 21.4 miles to the North-east of the summit. The radar domes have been omitted from the profile. The lower image was composed using USGS map data.

Radar domes on Black Mountain, Nevada. These are the same domes that appear at the start of the S-30 footage

Having taken place inside the range, the most likely explanation for the UFO would seem to be that it was a top secret 'black project' which for some reason was allowed to fly in full view of the surveillance cameras. However, according to one anonymous source in the 'Sightings' programme, the camera operators are not exposed to such tests of new technologies, the camera lenses being capped and the equipment turned off during such occasions.

Part 2: Appearance
https://www.aenigmatis.com/nellis-ufo-video/part-two/nellis-2.htm

Figure 2 In this and the Figures which follow, the original Nellis UFO image is shown on the left and the author's model on the right. Times are shown in UTC in each case.

The side lobes are seen to involve semicircular structures which line their perimeters, and the two projections are seen to originate from the trailing edges. The port projection looks to be deployed at a lower angle than that on the starboard side. The front and tail units are now much clearer and their relationship to the rest of the body can be discerned.

Figure 5 (Upper) As the UFO rotates, the starboard lobe projection can briefly be seen. (Lower) The frontal unit rotates to its fullest extent, so that the 'shield' is facing fully forward.

Although much has been said about the object's changing shape throughout the footage, the model, together with careful frame by frame analysis, suggests that this is partly a misperception. Abrupt changes in the camera exposure often give the misleading impression of a shape change. In addition, poor image contrast causes the depth perspective to be lost on many occasions, as the various features of the object appear to merge into one.

Part 3: Performance
https://www.aenigmatis.com/nellis-ufo-video/part-three/nellis-3.htm

Between 23:20:45 and 23:20:53 (UTC) it descends slightly, then it levels out and starts climbing (Figure 1). Its velocity appears fairly constant throughout this period, although this is difficult to determine because the object's relative approach angle to the camera is uncertain.

Figure 1 A montage of the Nellis UFO's movement in front of the distant mountain range during the early part of the S-30 footage. The UFO's position is shown at 2 second intervals.

Two sections of the early footage give an indication of the object's manoeuvrability. Judging by the position of the dark 'frontal unit' and the discernible 'tail unit' (see Part 2) the object appears to move sideways on two occasions; from 23:20:56 to 23:21:18 and from 23:21:21 to 23:21:29. The second period is of greater importance because of the object's better clarity, and a montage of its movement is shown in Figure 2. The object initially travels front forward, but it rotates to starboard (right) of track at 23:21:20. It then rises (at least, relative to the line of sight) before moving sideways (to port) for five seconds after 23:21:23. This motion can clearly be seen against the dark layers of cloud. It then sways back to port and regains forward-facing flight. Evidently the object is capable of rotating (yawing) during forward flight, and of moving sideways; techniques it seems to use in order to adjust its flight path.

Figure 2 Montage showing the UFO's second period of sideways motion

Any attempts to estimate the object's size are complicated because of the uncertainty of its distance throughout most of the S-30 footage. However, for the purposes of this exercise it is reasonable to assume that the range data is accurate when the object is between 12795m and 11705m from the tracking station. Since this occurs before the camera zooms in, and the width of one degree in azimuth is known, the object's height can be estimated by triangulation, and is found to be 8.7m ± 2.5.

Transcript
https://www.aenigmatis.com/nellis-ufo-video/transcript.htm

E = External Controller M = Male Controller F = Female Controller

M: "Its a helicopter!"
F: "Aaah!"
M: "That's why its so slow."
F: "Might be some kind of debris."
F: "It's not much more than a round dot, but it looks different to most dots."
E: "[unintelligible] ..two zero...one one zero level, okay...heading North at this time."
F: "Got any ideas what it is?"
M: "I got a helo?"
F: "You've got a helicopter?"
M: "Yeah - can't get a result on these things!"
E: "[unintelligible]... two five two ...[unintelligible]"
M: "I don't know what the hell that is - that's a helo, isn't it?"
M: "[chuckle] ... What is that? I don't know! ... I've no idea!"
E: "[unintelligible] ... flight level ... [unintelligible simultaneous talking]"
F: "Looks like one. Right up high now, goin' like .. straight up!"
M: "Its a balloon, ain't it? I don't know what the hell that is, man!"
F: "I think it's a helicopter."
M: "[unintelligible] ... forget it! ... data on him."
F: "Straight up, boy!"
M: "I'm outta here!"
F: "Oh, okay."
M: "What the hell is it? ... I'm gonna lose it in the sun, [unintelligible]"
F: "Call sign?"
M: "Err ... I don't even know what it is!"
M: "Must be at eleven thousand feet a minute." (?)
F: "It's weird-lookin'!"
E: "[unintelligible] .. non-FLIR!" (?)
E: "Non-FLIR!" (?)
F: "See him?" (?)
E: "[unintelligible] ... non-FLIR, non-FLIR!" (?)
F: "See him?" (?)


Video

A decade or so ago there were high quality rips of the VHS available online. I regret not saving them. Unfortunately, all the copies I can find online today suffer heavily from generation loss. This is, as far as I'm aware, the highest quality public version:



However, it is interlaced. There is a slightly lower quality, but de-interlaced, version here:

 

[LorentzHall]

Anyone have ideas on this one? Maybe some kind of strangely shaped targeting balloon moving in extremely unusual wind conditions?

(Only problem is of course: aren't targeting balloons fairly common around the Nellis Test Range? Why wouldn't tracking station operators with all this equipment, in daytime, recognize one?)

 

[Mick West]

The movement seems very consistent with a balloon, so that's my immediate #1 hypothesis. Helicopter would be #2.

The shape is odd, it looks more like a bunch of balloons than a single balloon.

Nellis air force range is large, but it does not seem implausible that a bunch of ballons might have drifted in from outside.

 

[Domzh]

to me it looks like 3 balloons or 3 chutes and a light payload underneath.

the form is changing sometimes and what i believe could be a light payload is sometimes not under but horizontal to the balloons / chutes.

my money is actually on chutes because when the wingload is not high enough, they can easily be dragged around in the wind and change their formfactor.

 

[ParanoidSkeptic2]

he movement seems very consistent with a balloon, so that's my immediate #1 hypothesis. Helicopter would be #2.

I agree with that, but just to clarify, the erratic movement (the really quick jolts) are just the camera moving to it right? It seems a lot of people think the erratic movement is made by the object.

 

[Mick West]

the erratic movement (the really quick jolts) are just the camera moving to it right

It looks like camera movement to me.

 

[ParanoidSkeptic2]

It looks like camera movement to me.

Agreed.

 

[getcaughrandom]

(reposting my post from another website).

https://www.aenigmatis.com/nellis-ufo-video/part-two/nellis-2.htm
The white-hot and black-cold parts of the the IR return is not something that can be just merely traced over. Much of the IR signature can blend in with the sky and be pretty much invisible in the IR camera, so an IR image is in no way representative of what objects actually look like in the visible spectrum.



Source: https://www.youtube.com/watch?v=Z9WlCpMnlZM


From 3:37 until the end of the video, you can see the black dot get larger and larger as it gets closer to the camera, and bank away at the end of the video (6:00+).


Keep that in mind.


From 5:50 until the end of the video (more apparent from 6:00 on), you can clearly see the hot jet exhaust plume of two jet turboprops (low-bypass turbofans generate significantly larger plumes; so I can easily identify this as twin turboprops with the white-hot twin nacelles of the aircraft). This is clearly shown at 6:00 on as the object banks away.


The white hot hot signature blobs is either an IR jammer, or just a reflection off the hot sun radiating from the object, as both will have the same effect at longer distances.


The only aircraft that fits this description that I can think of is the odd-looking OV-10 Bronco (https://en.wikipedia.org/wiki/North_American_Rockwell_OV-10_Bronco) with the AN/ALQ-144 IR jammer (https://en.wikipedia.org/wiki/AN/ALQ-144). This aircraft has one of the best low-speed flight characteristics of any military fixed-wing aircraft; yet can be quite a performer in the low-to-mid subsonic flight regimes (can go slow, then go relatively fast at a moments notice - Excellent characteristics for an observation and light-attack aircraft).


That cold dark spot? It has a large airconditioned crew cabin relative to its size (for a aircrew of 2). That black dark cold spot is its large bulbous cockpit nice and cool inside. Also, the undercarraige of the aircraft away from the jammer and/or the hot desert sun beating on the topside of the aircraft.


However, active squadrons of the OV-10 has been disbanded right around Desert Storm (~1991). This video takes place in 1995. I do know they continued to use these in test squadrons, and have been reactivated from time to time to assist in special operations to this day.

In the clearer video:

Source: https://www.youtube.com/watch?v=yD5eTCaBAcg

From 2:55 and on, you can REALLY see the twin engine nacelles and their exhaust plume of the turboprops.

 

[SkepticSteve]

Stabilized footage.

 

[JMartJr]

Te shape is certainly suggestive of a radar reflector, but you'd think they'd notice and video whatever it is dangling under were that the case.
ANd he match is only very approximate to any design I can find in a quick google search.


The shape is also very reminiscent of a "UFO Rotor Kite," but those kites fly through the Magnus Effect, which means they only fly when spinning rapidly, which this object is not doing. But as a point of reference, here is what one looks like. The size/shape of the lobes can vary quite a bit, as can the size f the kite. But spinning is the sine qua non of this design, so rule it out.

 

[Rocky]

Could it be a fan powered paraglider? Longshot guess.

 

[RatkingDBK]

I'd like to revisit this one because it doesn't seem to have been solved and has been reposted on reddit recently. Here is stabilized footage that was produced following the release of the UFO video. My first thoughts were that this was a group of balloons, as users have previously suggested.

https://www.dailymotion.com/video/x4tyze0

Chip Peterson (aerospace engineer) is the source of the stabilized video. He appears in this TV segment and shows the stabilized footage as well as a 3D representation of the object flight path throughout the course of the video.


Source: https://youtu.be/T7mEAuzHBXg?t=349


Chip goes on to say that the abrupt movement at the beginning of the simulation could not be the result of wind. He also says that the object remains at a constant distance from the camera as if it were observing the camera itself. Does this mean that it can't be a group of balloons? Is it possible that Chip Peterson produced a faulty 3D simulation?

 

[FatPhil]

Source: https://youtu.be/T7mEAuzHBXg?t=349

A debunking of that would contain 5 times as many lines as were spoken in it, as almost every thing said in it was wrong, or logically unsound. They don't seem to understand glare, for a start, or occultation thereof. "Changing shape", I don't know whether to laugh or cry.

 

[ideamug]

This one is a good one to bump.

 

[john.phil]

This one is a good one to bump.

It's just an insect. I have tweaked the video a bit, cropped and selected a section where the insect's features are more noticeable. At moments, the little wiggling legs and antennae are visible. The wings are just a blur on the right hand side for most of the video, depending on the orientation of the body in respect to the camera.

 

[ideamug]

It's just an insect. I have tweaked the video a bit, cropped and selected a section where the insect's features are more noticeable. At moments, the little wiggling legs and antennae are visible. The wings are just a blur on the right hand side for most of the video, depending on the orientation of the body in respect to the camera.

Did they not pick it up on radar showing 10k feet elevation? Couldn’t be an insect, no?

 

[MapperGuy]

Did they not pick it up on radar showing 10k feet elevation? Couldn’t be an insect, no?

I don't see any mention of 10k feet in this thread, is it in one of the videos?

At first glance it looks to me like a large insect. Changes in apparent shape and irregular flight path are certainly what you would expect in a video of a bug in flight.

It is possible for there to have been two things in the area, an airplane at 10k feet and a bug 10 feet from the camera.

 

[Mick West]

Marik suggested I put this one into Sitrec. I like that Peterson had a Sitrec-like recreation back in the 1990s



It would be good to A) verify this, and B) extract more info, like size, and speed.

At a minimum, I need the first frame for each unique AZ, EL, and RNG value. This should be in a spreadsheet, one sheet each for each of AZ, EL, and RNG

e.g. AZ is
0, 354
106, 355
346, 357
470 358

I'd suggest using this one with frame number overlaid
https://www.dropbox.com/scl/fi/eg0f....mp4?rlkey=93n4fjxpxmemqra1unerj5tjs&e=1&dl=0

And you can start at frame 5400, as that's when there's the first clear shot of the object so only half the video. But they seem to be tracking it the entire video, so maybe do it all.

 

[john.phil]

At a minimum, I need the first frame for each unique AZ, EL, and RNG value. This should be in a spreadsheet, one sheet each for each of AZ, EL, and RNG

I'm attaching the information extracted from the frames in CSV format. Some of the numbers in the footage can be hard to tell apart such as 3, 5, 6, 8 and 9, so I have stacked and enhanced the best related frames to improve readability (also attached).

 

[flarkey]

It's just an insect. I have tweaked the video a bit, cropped and selected a section where the insect's features are more noticeable. At moments, the little wiggling legs and antennae are visible. The wings are just a blur on the right hand side for most of the video, depending on the orientation of the body in respect to the camera.

This is a good segment @john.phil , very interesting. - I hadn't noticed this before but it does look very like an insect in that part of the video. The question then is - could an insect close to the camera & zoomed in look like it does in the other parts of the video due to glare from the sun on translucent and rapidly flapping wings, blur, lens flares, bokeh etc, - ie all the known phenomena that we know occur in cameras? Plus we'd have to assume an error in the RNG data, or that the RNG value was for something else (or at max).

 

[Max Phalange]

The range data does freeze from some point near the end of the video, so does not reflect the actual range estimate during that segment. But otherwise the range is in the thousands of meters, which would rule out a small object such as an insect.

https://www.aenigmatis.com/nellis-ufo-video/part-three/nellis-3.htm

At 23:21:35 the range display freezes at 9135 metres. Previous researchers have concluded from this that the UFO kept a fixed distance from the camera from this point onwards, whilst continuing to move forward at high speed. If this were correct, the object's ground track during this period would be perfectly circular, and its flight profile would be very peculiar. Figure 3 (upper) shows the cumulative flight profile of the object based on the range data shown in the footage. The first section of the profile covers a very large distance and it shows a gentle climb followed by a gradual descent. According to the range data, the object would have turned abruptly on many occasions during this part of the plot, covering very large distances in short periods of time. When the range finally settles on 9135m, i.e. when the object commences its wide arc, it is seen to climb sharply, gradually levelling off as it passes the station.

Figure 3 (Upper) The flight profile of the UFO according to the range data displayed in the S-30 footage, and (Lower) the flight profile of the UFO according to the author's straight-line ground track hypothesis. Note the vastly differing distances for each profile.

Having studied the footage closely, I believe the entire upper profile in Figure 3 is incorrect, for the following reasons. Firstly, the fixed range figure does not seem to reflect the increasing apparent size of the object, which is clearly getting closer to the station

 

[flarkey]

The range data does freeze from some point near the end of the video, so does not reflect the actual range estimate during that segment. But otherwise the range is in the thousands of meters, which would rule out a small object such as an insect.

https://www.aenigmatis.com/nellis-ufo-video/part-three/nellis-3.htm

It would only rule out an insect if the range data is correct. The range data could be giving the range to whatever is behind the small object, such as a distant hill.

@john.phil 's attachment Full.csv looks like the following graphs when Distance to UFO, Azimuth and Elevation are plotted. I haven't fully digested what they mean yet. I suppose the RNG data could suggest that the object is showing instantaneous acceleration to high velocities away from and then back towards the camera, and then maintaining an exact 9135m distance away from the camera, which shows it was sentient and aware that it was being observed. Or, the RNG data is either inaccurate, inconsistent, or wrong.

(Horizontal axis is frame number.)

 

[john.phil]

Full.csv looks like the following graphs when Distance to UFO, Azimuth and Elevation are plotted

There are two separate pieces of footage on the tape. One shows a bright dot, has a clear radar return and presumably accurate range, and the other is just an insect, possibly a hornet. The second piece of footage starts at Frame 5035. The timestamps for the first part range from 00:06:36 to 00:10:06, and for the second part: 23:20:31 to 23:23:18, thus clearly unrelated (23 hours apart plus the number of days, if any).

I have enhanced the first part of the footage to show the airborne target more clearly. Note that the apparent sudden movement of the airborne target happens when the camera goes to manual tracking mode, thus it's unlikely to be the movement of the target itself.

Now, the insect:

could an insect close to the camera & zoomed in look like it does in the other parts of the video due to glare from the sun on translucent and rapidly flapping wings

Yes, the four wings are clearly visible later in the footage, similar to the example below:

 

[Mick West]

I'm attaching the information extracted from the frames in CSV format. Some of the numbers in the footage can be hard to tell apart such as 3, 5, 6, 8 and 9, so I have stacked and enhanced the best related frames to improve readability (also attached).

Thanks! I shall put it into Sitrec later today.

BTW, I've set up Sitrec so anyone can create a sitch. It's somewhat hampered by the lack of documentation, but I'm gradually improving it.

https://github.com/MickWest/sitrec/blob/main/docs/CustomSitches.md

 

[Mick West]

First pass Sitrec:
https://www.metabunk.org/sitrec/?sitch=nellis

The location of the camera was suggested by Marik. I'm not sure how accurate it is.

There's a new menu option: "Segment" which lets you highlight portions of the track. The first one (0-4404) is a straight line at constant speed. That's not something that can happen by accident while the Azimuth is sweeping across.

So that appears to be real: an object at 16000 feet, moving at 100 knots ground speed (air speed is unknown, as it depends on the wind)



Then there's a segment where the camera swings around, not locked on anything. The object appears towards the end of this, so the last swinging segment is probably wrong (not too important)


Then there's the apparent rising up into the air. Very noisy, and the constant RNG suggest it's inaccurate.


The rather dramatic spike in RNG before that also seems to be a glitch.



We don't know the FOV, and the offset of the object in the frame is not considered, but it won't make a big difference to the big picture.

 

[john.phil]

10k feet elevation

The operator reads the range in km.

(02:00 - 02:07) "18 degrees, 18.6 degrees elevation, 10.8 degrees...err...kilometers range." <- At this moment the screen reads AZ 19A, EL +18A, RNG 010875A.

 

[john.phil]

Then there's a segment where the camera swings around, not locked on anything. The object appears towards the end of this, so the last swinging segment is probably wrong (not too important)

This is after the simulated "kill", the operator then switches to manual mode and rotates the camera abruptly, away from the airborne target.

Then there's a segment where the camera swings around, not locked on anything. The object appears towards the end of this, so the last swinging segment is probably wrong (not too important)

There are two objects, as the second part of the footage is unrelated to the first, it starts 23 hours later (plus any number of days, and if you assume the timestamps in the footage to be accurate). The second object is an insect. The first object can be seen as a bright dot. Enhanced footage in Post #23 highlights the first object and its apparent movement when the tracking is switched to manual.

It might be worth splitting into two sitches to avoid confusion between the different sightings (as a suggestion: first footage ending at 5034, second footage starting at 5183).

EDIT: From the post below, S-13 (1st footage) and S-30 are two separate locations, thus we definitely should have two sitches in Sitrec.

 

[flarkey]

First pass Sitrec:
https://www.metabunk.org/sitrec/?sitch=nellis

The location of the camera was suggested by Marik. I'm not sure how accurate it is.

This video has footage from two locations, called S-13 and S-30, indicated by the text on the lower left of the screen. I haven't found anyofficial or unofficial list of where the S sites are in the Nellis Complex. The only one thats known is S-4 (Not the one made famous by Bob Lazar). https://www.lazygranch.com/s4.htm



We don't know where S-13 is. But the analysis website linked above (link) has a page regarding the S-30 location. It uses an image in the video that shows the bearing to a known peak - Black Mountain - and uses a reciprocal bearing to determine a location.

This is the image:


This is where the S-30 site is determined to be.

Consequently it would appear that the most likely filming location of the S-30 footage (and by implication, the location of S-30 itself) lies at a distance of 21.2 ± 2.1 statute miles North-east of Black Mountain, i.e. within a 4.2 mile NE-SW line centred on co-ordinates N 37º 31'.26, W 116º 23'.99. This is marked as a red line on the map in Figure 4.

I have checked this in Google earth by drawing my own reciprocal lines back from Black Mountain and its not too far off.

37.521000 -116.399833


There are a number of small installations around this area, presumably used for monitoring range activities. the nearest one is about 4km North of the suggested S-30 location




This is a close up in Google Earth - the shadows seem to suggest some sort of Radar or Turreted Camera on top of the building on the left. Remember that this UFO video is nearly 30 Years old and the range has undoubtedly been upgraded by then, plus we dont have Google Earth Imagery from 1994.

 

[flarkey]

First pass Sitrec:
https://www.metabunk.org/sitrec/?sitch=nellis

Hmm, something doest seem quite right to me here.

At Frame 5623 (bottom right of next image) we can see the peak of Black Mountain on a camera bearing of 219, but the camera in sitrec seems to be on the reciprocal bearing of about 040.



Here's the view above recreated in Google Earth for comparison.

 

[Mick West]

Hmm, something doest seem quite right to me here.

At Frame 5623 (bottom right of next image) we can see the peak of Black Mountain on a camera bearing of 219, but the camera in sitrec seems to be on the reciprocal bearing of about 040.

Fixed, I think (09:44). I also added a compass.
https://www.metabunk.org/sitrec/?sitch=nellis

 

[Mick West]

There are a number of small installations around this area, presumably used for monitoring range activities. the nearest one is about 4km North of the suggested S-30 location

I'll try that in a bit. Off for a walk!

 

[Mick West]

https://www.metabunk.org/sitrec/?sitch=nellis

So I chopped it down to just the S-30 portion. Added the radomes exactly where they should be, and the mountain profile is a good match.

It's very obvious that the range value is not working, because when the range changes rapidly, the object and the cloud bands don't change size. The clouds not changing size means the zoom remains constant. The tripling of the range value with no change in object size means it's not the range to the object

Then when the range value is constant, the object seems to get closer - there is some zooming here (we can see the cloud bands expand). However the path here is an oddly geometric arc, so again it seems like the range indicator is not working.

I'm not sold on the insect hypothesis, as later in the video it looks a lot more like some balloons rotating.

 

[Mick West]

Keep in mind the Sitrec recreation is based on very low resolution data (Az and El) which does not capture:

A) The precise angles the camera - the field of view is about 2° vertically, and Az and El are only accurate to about 1°, which is half the screen.
B) The movement of the object in the frame - which is often considerable. (this could be tracked and used to refine the LOS)
C) The changes in FOV which are very hard to determine. This affects B.

When hills are visible, we see motion of the camera that is not reflected in A (the Az/El angles), and then we see motion of the object in the frame. So we get the earlier manual composites that should be much more accurate for this portion.