By Andres Duarte and Mark Gonzalez (Group Canopus)
a couple of months ago came to the Canopus box The rare photograph shown above. The image, sent by a biochemistry student, was caught in the river Trancura in Pucón (Ninth Region). The intention of the photographer was to capture a group of people practicing rafting. With difficulty can be seen from a distance the rafts that move over the waters of Trancura. However, this circumstance was pushed into the background when the image then watched as the sky appeared a dark plate-shaped object that no one saw the place. A UFO ghost! Regarding UFO obvious an awkward detail that should trigger our alarms: The object is very dark. As is known, the scattering of light in the atmosphere depends on the distance between the observer and an object sighted. The farther you are an opaque body (which does not have its own light), brighter be seen in a photographic record. On the contrary, the closer the object is found, the darker it will look, due to low light scattering produced there. Judging by showing a snapshot, it seems to be the case.
A closer look at the picture, played by Andres Duarte (Canopus analyst) not only confirms this suspicion, but also to know an estimated value of the camera-object distance and size of it:
Data
photography
According to the EXIF \u200b\u200b(specifications for image file formats used by digital cameras, embedded within them), here are some relevant data we can draw from the picture:
number f (N ) = 4.50 ( is the ratio of the focal length effective aperture diameter )
Focal Length (f ) = 25.10 mm ( is the distance between the focal point and the surface of the lens )
EXIF Image Height = 2,272 pixels
The dimensions of the camera sensor are: 5.27 x 3.96 mm. Then use the value of the width of sensor ( d ).
Determining a value for the camera-object distance
The circle of confusion is the blurred image of a point source of light. The blurred image is a convolution between the image sharp, and the circle of confusion, then the latter is obtained by deconvolution. In this case, the diameter of the circle of confusion (coc ) is about 20 pixels. Using this data we can obtain a new value for this variable ( Coc), but expressed in millimeters :
Coc = (coc xd) / Height image = (20 pix x 5.27 mm) / 2272 = 0.046 mm pix
Since the picture is focused at infinity, we use the formula circle of confusion for pictures focused at infinity and obtain the distance (S ) between the object and the camera:
S = f ^ 2 / (N x Coc) = (25.10 mm) ^ 2 / (4.50 x 0.046 mm) = 3040 mm (about 3 meters)
Once restored image, you can argue that the alleged UFO has a length in the photograph ( L ) of about 40 pixels.
Determining a value for the length of the object
Then, from the width of the sensor we get the horizontal visual field of the photo ( field of view):
FOV = 2 x atan (d/2f) tie = 2 x [5.27 mm / (2 x 25.10 mm)] = 12 °
angular size (t ) the object is:
t = (L x FOV) / Height image = (40 pix x 12 °) / 2272 = 0.2 °
pix
Then, the linear size of the body is:
2 x S x tan ( t / 2) = 2 x 3,040 mm x tan (0.2 º / 2) = 11 mm
According to the camera-object distance (3 meters) and the angular size of (0.2 º ), the alleged UFO has a length of about 1 cm.
From this analysis it is possible to infer that the purpose of photography is probably just a bug.
If you wish to contact Grouping Canopus, write email: acanopus@gmail.com
