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Air-France flight 3532 sighting, January 28, 1994

Note: This page relates only to the question of the angular size of the observed phenomenon. It is in no way an overall representation of the incident.

Angular size of the observed phenomenon:

1. Sources:

2. Summary Table:

Ref.: Type of source: J.-C. Duboc: V. Chauffour: J.-J. Vélasco: Others:
ta1 Form. 1/2 of the diameter of the moon. N/A. N/A. N/A.
ta2 Form. N/A. Nothing. N/A. N/A.
ta3 Paris-Match magazine. Nothing. Nothing. N/A. Nothing.
ta4 Article in the scientific journal JSE. Nothing. Nothing. Nothing. Nothing.
ta5 VSD OVNIS Magazine. Nothing. Nothing. N/A. Nothing.
ta19 Facteur X ufology magazine. Nothing. Nothing. N/A. N/A.
ta6 Web page by Eric Maillot. N/A. N/A. N/A. Nothing.
ta7 COMETA report. Nothing. Nothing. N/A. Nothing.
ta8 Witness interview by ufologist. Nothing. N/A. N/A. N/A.
ta9 Witness interview on TV. Nothing. N/A. N/A. N/A.
ta10 Witness interview on TV. N/A. N/A. N/A. N/A.
ta11 Witness interview on TV. Nothing. N/A. N/A. N/A.
ta12 Witness interview on TV documentary. Nothing. N/A. N/A. N/A.
ta13 Book by investigator JJV. Uncertain, small finger at arm's length. Uncertain, small finger at arm's length. Small finger at arm's length. Uncertain, small finger at arm's length.
ta14 Witness interview, ufology radio show. Nothing. N/A. N/A. N/A.
ta15 Witness interview, ufology radio show. Nothing. N/A. N/A. N/A.
ta16 TV show. Nothing. N/A. The thumb at arm's length. N/A.
ta17 Eric Maillot. N/A. N/A. N/A. 1/2 of the moon.
ta18 Web page indicated by witness. 6mm, a quarter of the thumb at arm's length." N/A N/A N/A
ta21 GEIPAN web page. Nothing. Nothing. N/A. Nothing.

3. List of Issues:

Id: Topic: Severity: Date noted: Raised by: Noted by: Description: Proposal: Status:
1 Data Severe May 5, 2007 Patrick Gross Patrick Gross No investigation report available. Help needed. Open.
2 Ufology Severe May 5, 2007 Patrick Gross Patrick Gross Among 3 witnesses, only 1 provides an angular size. Help needed. Open.
3 Ufology Severe May 5, 2007 Patrick Gross Patrick Gross No information on method of estimate of angular size. Help needed. Open.

4. Synthesis:

Mr. Jean-Charles Duboc indicated an angular size twice: the first time by filling an official ufology sighting report form, indicating a size equivalent to that of half of the apparent size of the moon [ta1], the second time by quoting a web page about the sighting as indicating an angular size corresponding to the apparent size of a quarter of the thickness of the thumb at arm's length, approximately 6 millimeters [ta18], which is consistent with his first indication. I did not find any contradictory statement of the witness on this matter.

No angular size was indicated directly by the two other witnesses, in the sources that are available to me, which is very unfortunate. A case with multiple witnesses is not really a multiple witnesses case if only one witness provides information.

To get witnesses to fill a "Dimension:" field on a form is in no way a valid method. Here, only Jean-Charles Duboc realized that an angular size was the only information that makes sense, the copilot providing as answer "very big", which is quantitatively meaningless.

Mr. Jean-Jacques Vélasco, at the time of the SEPRA within the CNES, indicated in his 2004 book an angular size corresponding to the apparent size of a small finger at arm's length, i.e. approximately 18 millimeters. In a general public TV show in 2007, in the presence of the witness Jean-Charles Duboc, he indicates in an angular size corresponding to the apparent size of a thumb at arm's length, i.e. approximately 25 mm.

This is a rather odd situation, in which the angular size given initially by the witness had been tripled, then quadrupled.

The manner in which the size angular was measured, or estimated, is indicated nowhere by anybody. A request that I made on this matter did not receive an effective answer.

At the best of what can be deduced on the matter, it seems that the angular size of the UFO was about that of half of full moon, that is to say about 15 arc minutes.

If the UFO were indeed at a 46 kilometers distance, it corresponds to a real width of 200,70 meters. This is a figure which appears in several sources, but itself prone to variations from one source to another.

The following table gives various examples of an approximate real dimension of a 15 arc minute at various distances:

For a distance of: The object's width would be at:
100 meters 45 centimeters
1 kilometer 4.30 meters
5 kilomètre 21 meters
10 kilometers 43 meters
15 kilometers 65 meters
20 kilometers 87 meters
30 kilometers 130 meters
40 kilometers 175 meters
46 kilometers 200 meters
50 kilometers 218 meters
80 kilometers 350 meters
100 kilometers 436 meters

5. Document History:

Version: Created/changed by: Date: Change description:
0.1 Draft Patrick Gross March 27, 2007 Creation: [ta1] to [ta9] and [ta11] to [ta17]
0.1 Draft Patrick Gross March 27, 2007 Communicated to the members of the Internet discussion list "L'Observatoire Zététique" for comments, corrections, possible additional information.
0.2b Draft Patrick Gross March 28, 2007 Addition for [ta1] and [ta2] of the paragraph: "The date of filling of the form is undoubtedly after 1997. The form is said to be a part of a "Synthesis of the report of investigation for the SEPRA" by Dominique Weinstein and Patrick Leprevost for the SEPRA, dated '2001 Weinstein/SEPRA'." Addition of [ta18]. Addition of [ta19] as unavailable source. All these additions were made following information by Eric Maillot after the day before communication to the members of the discussion list "L'Observatoire Zététique".
0.2c Draft Patrick Gross March 28, 2007 Addition de [ta20].
0.2d Draft Patrick Gross April 1, 2007 Addition of content for [ta19].
0.2e Draft Patrick Gross April 29, 2007 Addition of the original version in English for [ta4], and addition of [ta21].
0.2f Draft Patrick Gross May 6, 2007 Addition of the Summary Table, the List of Issue and the Synthesis. Creation of the English version of the document.
0.3 Productive Patrick Gross May 6, 2007 First announced publication on the author's website www.ufologie.net in the "site updates" section and publication URL defined. Information thereof sent to the discussion list "L'Observatoire Zététique" for possible late comments.
1.0 Productive Patrick Gross June 21, 2007 Conversion from HTML4 to XHTML strict.

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