Résumé

Le négatif d'origine du film du Costa Rica d'un objet ovale aérien en forme de disque a été obtenu et analysé avec soin. Non seulement il n'y avait aucun indice de défauts optiques, canular délibéré ou autre élement soutenant d'autres explications prosaïques de l'image du disque, mais également d'intéressants nouveaux détails de surface ont été trouvés, tous possédant la même orientation oblique. L'objet en forme de disque reste non-identifié.

Dans notre article d'origine, "Analyse photo d'un disque aérien au-dessus du Costa Rica" s1(Vol. 3, No. 2, p. 113-131), nous avons conclu en disant que nous essayions d'obtenir le négatif d'origine de l'objet non-identifié, photographié par chance lors d'une mission de cartographie aérienne pour étude ultérieure. De fait, nous étions préoccupés par le fait que certaines suggestions de nos relecteurs pourraient nécessiter des tests plus stricts que nous pouvions en mener sur un négatif de 2^nde génération. Nous sommes ravis d'indiquer qu'à travers les efforts de Peter Sturrock, Jacques Vallée et Ricardo Vilchez de San Jose, au Costa Rica, nous avons reçu 3 images reliées (n° 299 à 301) du négatif noir et blanc d'origine le 11 février 1990.

Comme on pourrait s'y attendre, plus de détails fins sont visibles sur le négatif d'origine que sur la copie et ces détails sont particulièrement intéressants. Plusieurs points méritent un commentaire plus poussé sur la base d'une inspection visuelle minutieuse unaided and magnified de ce nouveau négatif et d'aggrandissements de tirages positifs de contrastes différents qui furent réalisés. La figure 1 est un aggrandissement à fort contraste du disque effectué à partir du négatif d'origine.

1. The oval disc image is present in the same relative location on frame 300 as already described in our first article. Also, the entire film plane on frames 299, 300, and 301 is flat with absolutely no protrusions or depressions anywhere. The thoughtful comments by our original reviewer in this regard were shown to be unsupported.
2. The emulsion side of frames 299 and 301 possessed several small, irregularly shaped developer stains which only affected the specular reflectivity of the emulsion, but did not in any way influence the transmissivity of the film. These stains were completely invisible except when the film was viewed against a diffuse, glancing, reflecting light source. No stains were found at any place on frame 300, the frame on which the image of the disc was located.
3. There are a number of long linear scratches (mostly on the non emulsion side) running parallel to the edge labelled with the Kodak Safety Film markings running east-west. It is apparent that the negative has received rough usage over the years. There are three very thin parallel scratches running through the image of the disc as well that are visible in Figure 1.
4. The individual film grains were somewhat more apparent on this original negative throughout all three frames as compared with the second generation negative, as would be expected. They appeared to be randomly spaced and possessed random diameters as well.
5. Our examination of the original negative confirms our initial speculation that the image of the disc is not the result of a double exposure, a reflection, a deliberate paste-up, or other kind of hoax.
6. There appears to be a very interesting obliquely oriented micro- and macrostructure detail on the image of the object itself. Figure 2 is a drawing of the disc that indicates the location of this detail.

Referring to Figure 2, the left-hand edge (L) consists of dozens of thin, parallel fingers of light that originate in the "body" of the object and fade off into the background luminance. The tips of these fingers end approximately along a curved line that corresponds to the oval shaped outline of the disc's form. The right-hand edge (R) possesses a much more regular (smooth) contour than the left but also possesses many very short jagged lines of light, each of which is oriented in the same direction as the longer fingers discussed above. The line labelled X-Y is the orientation of all of this microstructure just described. There are even some very short jagged lines with this orientation found along the inner edge labeled (z).

Three other details having this same orientation are also of note. They are (a) the upper and lower edges of the disc labelled (d') and (d), respectively, (b) a relatively long, thin, dark line that originates at the central dark region, which is labelled (n), and (c) the alignment of the two dark regions near the middle of the disc. We have no clear understanding of the origin or meaning of this oblique orientation effect seen in so many of its surface details.

On the basis of a very careful examination of the preceding and following frame, under different levels of magnification, it is clear that a second image of this aerial disc is not present in either one (unless it is concealed behind a dense cloud). Therefore, it must have flown into and then out of the field of view of frame 300 within a 20 second period of time or otherwise become invisible. Assuming that the object did not simply disappear, but travelled in a straight line, it is possible to calculate its maximum speed of travel. Assuming that the disc flew along a straight west to east path at ground level, it would have had to travel at about 1,988 miles per hour to traverse the entire distance from its current image location on frame 300 to just beyond the eastern edge of frame 299 (a distance equivalent to 11.04 miles). Likewise,