Within Size Errors
The Better Way To Describe A UFO
Reports are stronger when witnesses describe angles, timing, direction, and reference points before estimating size or speed.
On this page
- Angular size versus physical size
- Angular speed versus claimed miles per hour
- Reference points that improve later identification
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Introduction
When people report a UFO, the most valuable information is often not a guess about how large, fast or distant the object was. Those estimates depend on knowing the range to the object, and range is usually the least certain part of a sky observation. A report becomes much more useful when it preserves what was directly seen: how much sky the object covered, where it appeared relative to landmarks, how long it remained visible, and how it moved against known reference points. Investigators from Allan Hendry’s classic UFO fieldwork through modern UAP studies by NASA and the All-domain Anomaly Resolution Office (AARO) have repeatedly stressed that angular observations are often more reliable than witness estimates of physical size or speed. [Skeptical Inquirer]skepticalinquirer.orgSkeptical InquirerUFO Identification ProcessNovember 1, 2018 — As UFO investigator Allan Hendry (1979, 6) aptly noted, “We only get to st… [AARO]aaro.milParallax effects cause the object to be.Read moreAAROEffect of Forced Perspective and Parallax View on UAP…As the airborne observer moves from position 1 to 2 to 3 in the air, they vi…
In the context of sincere UFO reports, angular measurements help separate observation from interpretation. They preserve evidence that can later be compared with aircraft tracks, astronomical objects, balloons, satellites and other potential explanations.
The Difference Between What Was Seen And What Was Inferred
A witness sees an object as an angle in the sky. The eye does not directly measure metres, kilometres or miles per hour. Those quantities are inferred after the observer makes assumptions about distance.
This distinction is crucial because a mistaken distance estimate automatically distorts size and speed estimates. A small nearby object and a large distant object can occupy the same angular size in the observer’s field of view. Likewise, a slow object nearby can appear to cross the sky as quickly as a much faster object farther away. Investigators have long noted that distance, size and speed estimates are tightly linked, making them unreliable when range is unknown. [Skeptical Inquirer]skepticalinquirer.orgSkeptical InquirerUFO Identification ProcessNovember 1, 2018 — As UFO investigator Allan Hendry (1979, 6) aptly noted, “We only get to st…
A stronger report therefore begins with statements such as:
- “The object appeared about half the width of the Moon.”
- “It moved from the church steeple to a point above the water tower.”
- “It crossed that distance in roughly eight seconds.”
- “It disappeared behind the tree line.”
These observations can be checked later. Claims such as “it was the size of a football pitch” or “it was travelling 5,000 mph” usually cannot.
Angular Size Versus Physical Size
Angular size describes how large an object appears from the observer’s position. It does not require knowing the distance.
Astronomers routinely use angular measurements because they are directly observable. The Moon, for example, appears about half a degree wide in the sky. Witnesses can often estimate an unknown object’s angular size by comparing it with familiar references:
- The Moon.
- A fingertip held at arm’s length.
- The width of a nearby building.
- The spacing between visible stars.
AARO’s discussion of forced perspective highlights why this matters. An object with a fixed angular appearance can correspond to dramatically different physical sizes depending on its true range. The farther away the observer assumes it is, the larger the inferred object becomes. [AARO]aaro.milAARO2025 UAP Workshop: Narrative Data, Infrastructures, and…February 12, 2026 — Ask witnesses to explain how they estimated size, dist…
Consider two witness statements:
- “It was as big as a house.”
- “It appeared roughly one-quarter the width of the full Moon.”
The second statement is generally more useful. Future investigators can combine that angular estimate with radar data, photographs, astronomical records or other information. The first statement already contains an uncertain distance assumption.
Simple Ways Witnesses Can Record Angular Size
Useful descriptions include:
- Comparison with the Moon.
- Comparison with a finger held at arm’s length.
- Apparent size relative to nearby structures.
- Whether the object appeared point-like or showed visible shape.
Even rough angular estimates are often more valuable than confident physical-size claims.
Angular Speed Versus Claimed Miles Per Hour
The same principle applies to motion.
Observers do not directly see miles per hour. They see an object move through an angle across the sky over a period of time.
A report stating that a light crossed “30 degrees of sky in ten seconds” contains measurable information. A report stating that it travelled “thousands of miles per hour” usually depends on an uncertain assumption about distance. [Skeptical Inquirer]skepticalinquirer.orgSkeptical InquirerUFO Identification ProcessNovember 1, 2018 — As UFO investigator Allan Hendry (1979, 6) aptly noted, “We only get to st…
This issue appears repeatedly in modern UAP investigations. AARO has emphasised that forced perspective and parallax can make stationary or slow-moving objects appear extremely fast. From a moving aircraft, for example, a distant object can seem to race across the background because of changing viewing geometry rather than actual extraordinary speed. [AARO]aaro.orgAssociation of Americans Resident Overseas: AAROThe Association of Americans Resident Overseas (AARO), founded in 1973 is a global, non-p… [The Black Vault]theblackvault.comaaro explores forced perspective and parallax in new uap analysis paperWhen viewed from a moving vantage point, a stationary…Read more…
The practical lesson is straightforward. Witnesses should describe:
- Start and end positions.
- Duration of movement.
- Whether motion was smooth, erratic or intermittent.
- Any visible changes in direction.
- Whether the observer was stationary or moving.
These details allow later calculations. A speed estimate made on the spot often cannot be independently checked.
Timing Matters More Than Speed Estimates
A stopwatch reading, phone timestamp or even a careful count of seconds can greatly improve a report.
For example:
- “Visible for approximately 45 seconds.”
- “Hovered for about two minutes.”
- “Crossed from west to east in ten seconds.”
Timing data can later be compared with aircraft, satellite and meteor databases. Estimated miles per hour usually cannot.
Reference Points That Improve Later Identification
One of the most useful habits is describing the object’s position relative to fixed landmarks.
A witness might record that the object:
- Appeared above a radio mast.
- Passed beneath a bright star.
- Moved between two hills.
- Vanished behind a building.
- Remained fixed relative to a distant tower.
These references provide geometric context that survives long after the event.
NASA’s UAP study stressed the importance of collecting better observational data because many reports lack the information needed for rigorous analysis. Precise positional descriptions help preserve information that can later be reconstructed or tested. [NASA Science]science.nasa.govNASA ScienceIndependent Study Team ReportThe study of Unidentified Anomalous Phenomena (UAP) presents a unique scientific opportunity tha…
Direction Of Travel
Direction is often overlooked but can be extremely valuable.
Instead of saying “it moved quickly”, a stronger report records:
- North to south.
- West to east.
- Towards the observer.
- Away from the observer. [aaro.mil]aaro.milParallax effects cause the object to be.Read moreAAROEffect of Forced Perspective and Parallax View on UAP…As the airborne observer moves from position 1 to 2 to 3 in the air, they vi…
- Parallel to a visible horizon.
Combined with timing and angular movement, direction can help investigators compare a sighting with known flight paths, satellite passes or astronomical objects.
Elevation In The Sky
Witnesses can also note approximate elevation:
- Near the horizon.
- Halfway between horizon and zenith.
- Directly overhead.
Even rough estimates help reconstruct what was actually observed. They are often more useful than guesses about altitude.
Why Investigators Prefer Angular Data
Modern UAP researchers increasingly emphasise structured reporting because eyewitness testimony is most valuable when it preserves observations rather than interpretations. AARO workshop recommendations released in 2025 specifically encouraged collecting information about how witnesses arrived at estimates of size, distance and speed rather than simply recording those estimates themselves. [AARO]aaro.milAARO HomeWelcome to the website for the All-domain Anomaly Resolution Office (AARO). Our team of experts leads the U.S. government's effo…
The reason is practical. Angular observations can later be combined with:
- Radar data.
- Flight records.
- Astronomical databases.
- Satellite tracking information.
- Photographs and video.
- Additional witness accounts.
Distance guesses made during a surprising event are much harder to verify.
For sincere witnesses, this is not about doubting what they saw. It is about preserving the strongest evidence. A report that carefully records angles, timing, direction and reference points gives later investigators a chance to determine whether an unusual sighting was a balloon, aircraft, satellite, astronomical object, atmospheric phenomenon or something that remains unexplained. By keeping observation separate from interpretation, angular descriptions turn a fleeting visual experience into information that can actually be analysed.
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Endnotes
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Source: aaro.mil
Title: Parallax effects cause the object to be.Read more
Link: https://www.aaro.mil/Portals/136/PDFs/Information%20Papers/AARO_Effect_of_Forced_Perspective_and_Parallax_View_on_UAP_Observations_2024.pdfSource snippet
AAROEffect of Forced Perspective and Parallax View on UAP...As the airborne observer moves from position 1 to 2 to 3 in the air, they vi...
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Source: science.nasa.gov
Link: https://science.nasa.gov/wp-content/uploads/2023/09/uap-independent-study-team-final-report.pdfSource snippet
NASA ScienceIndependent Study Team ReportThe study of Unidentified Anomalous Phenomena (UAP) presents a unique scientific opportunity tha...
-
Source: aaro.mil
Link: https://www.aaro.mil/Portals/136/PDFs/Information%20Papers/2025_UAP_Workshop_Paper.pdfSource snippet
AARO2025 UAP Workshop: Narrative Data, Infrastructures, and...February 12, 2026 — Ask witnesses to explain how they estimated size, dist...
Published: February 12, 2026
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Source: aaro.org
Link: https://aaro.org/Source snippet
Association of Americans Resident Overseas: AAROThe Association of Americans Resident Overseas (AARO), founded in 1973 is a global, non-p...
-
Source: aaro.mil
Link: https://www.aaro.mil/Source snippet
AARO HomeWelcome to the website for the All-domain Anomaly Resolution Office (AARO). Our team of experts leads the U.S. government's effo...
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Source: aaro.mil
Link: https://www.aaro.mil/Resources/Source snippet
ResourcesEffect of Forced Perspective and Parallax View on UAP Observations · Correlations of [Starlink]({{ 'starlink/' | relative_url }}) Satellite Flaring with UAP Observa...
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Source: aaro.com
Title: Your Partner in Group Reporting | CPM software & more
Link: https://aaro.com/en/Source snippet
Complete software, wide range of services, online support...Read more...
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Source: skepticalinquirer.org
Link: https://skepticalinquirer.org/2018/11/ufo-identification-process/Source snippet
Skeptical InquirerUFO Identification ProcessNovember 1, 2018 — As UFO investigator Allan Hendry (1979, 6) aptly noted, “We only get to st...
Published: November 1, 2018
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Source: skepticalinquirer.org
Title: Skeptical Inquirer UFO Identification Process Why Humanoid Aliens?
Link: https://skepticalinquirer.org/wp-content/uploads/sites/29/2019/03/SI-ND-18.pdfSource snippet
UFO investigator Allan. Hendry (1979, 6) aptly noted, “We only get to study reports of UFOs—not the UFOs themselves.” There i...
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Source: theblackvault.com
Title: aaro explores forced perspective and parallax in new uap analysis paper
Link: https://www.theblackvault.com/documentarchive/aaro-explores-forced-perspective-and-parallax-in-new-uap-analysis-paper/Source snippet
When viewed from a moving vantage point, a stationary...Read more...
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Source: documents.theblackvault.com
Link: https://documents.theblackvault.com/documents/ufos/Brazil/CENDOC_ENVELOPE_12_1979.pdfSource snippet
UFOS. SPA. VE. New. Zed visitors? AIK FURUE. Indignant [pilots]({{ 'pilots/' | relative_url }}) say. UFO report. Cover-up. PUT ON UF. ERT. Experts. Doubt. UFO. Claim. UFO写...
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Source: dvidshub.net
Link: https://www.dvidshub.net/video/992262/pr-013-unresolved-uap-report-europe-2022Source snippet
PR-013, Unresolved UAP Report, Europe 2022This unresolved report contributes to AARO's historical and locational trend analyses. VIDEO IN...
Additional References
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Link: https://www.researchgate.net/publication/341443875_Aliens_and_Unidentified_Aerial_PhenomenaSource snippet
(PDF) Aliens and Unidentified Aerial PhenomenaThe key similarities between UFO sightings and their long and continuous history recorded b...
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Source: academia.edu
Link: https://www.academia.edu/32089490/UFO_Reports_by_Time_of_the_DaySource snippet
(PDF) UFO Reports by Time of the DayA brief research note on the frequency of UFO reports plotted by time of the day in the FOTOCAT database...
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Source: reddit.com
Link: https://www.reddit.com/r/UFOs/comments/1gv8xak/aaro_has_resolved_the_go_fast_uap/Source snippet
AARO has resolved the "Go Fast" UAP: r/UFOsGo Fast explanation: paralax Object altitude 13.000 ft, speed 45mph / 39 knots. Wind speed at...
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Source: cufos.org
Link: https://cufos.org/PDFs/IUR%20issues/IUR%20Vol.%205%20No.%201%20Jan.%201980.pdfSource snippet
INTERNATIONAT REPORTERHOIY WE LEARN OF UFOS: UFO reoorts reach us from news departm'ents, civilian organizations and individuals all over...
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Link: https://www.researchgate.net/profile/Tim-Lomas/publication/390980555_The_UAP_Assessment_Matrix_A_proposed_framework_for_evaluating_evidence_and_understanding_regarding_Unidentified_Anomalous_Phenomena/links/681e7cc9df0e3f544f533a8f/The-UAP-Assessment-Matrix-A-proposed-framework-for-evaluating-evidence-and-understanding-regarding-Unidentified-Anomalous-Phenomena.pdfSource snippet
The UAP Assessment MatrixIn its latest report in November 2024, AARO stated that it has studied 1652 reports in total, with the report it...
Published: November 2024
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Source: space.com
Title: pentagon ufo chief tells senate very anomalous objects need careful study video
Link: https://www.space.com/space-exploration/search-for-life/pentagon-ufo-chief-tells-senate-very-anomalous-objects-need-careful-study-videoSource snippet
Pentagon UFO chief tells Senate 'very anomalous objects'...19 Nov 2024 — In that case, the object's apparent speed in the video was actu...
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Source: theforestawakening.com
Title: effect of forced perspective and parallax view on uap observations 35a2093a
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Effect of Forced Perspective and Parallax View on UAP...1 Jan 2024 — AARO explains how forced perspective and parallax effects can accou...
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Title: a new calculation on the fly to the nasa uap study 2dacaf860cac
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New Calculation on the Fly to the NASA UAP Study - Avi LoebA New Calculation on the Fly to the NASA UAP Study This morning, the weather f...
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Link: https://www.rev.com/transcripts/unidentified-anomalous-phenomena-independent-study-report-from-nasa-transcriptSource snippet
ile NASA is still working to evaluate the report and to assess...Read more...
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eye), I calculated its size to be 3 to 5 ft. for a height of 6-12 thousand feet, and a zenith an;le of about 450. This size estimate coul...
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