R e s e a r c h
Martin SHOUGH & Wim VAN UTRECHT
A photo of a possible mirage of a mountain was published on p. 157 of the June 1987 issue of the UK Journal of Meteorology. The photo is part of an article written by Edinburgh-based science and UFO writer Steuart CAMPBELL. The contents of the article is reprinted below. Because of its poor quality, we replaced the photo from the JoM article with a scan from a print of the same image published in CAMPBELL's book The UFO Mystery Solved (Explicit Books, Edinburgh, 1994, p. 57, Plate 3:3). In our quote, we mention the name of the principal witness/photographer in full. Other witnesses are only referred to by their initials.
Mirage of a Mountain?
On 19 December 1979, at 0845 GMT, Bransby Clarke, then of Archbank, Moffat (Dumfries and Galloway), was about to take his daughters to school when one of them drew his attention to a bright object in the southern sky. He described it as a stationary elongated oval, sharper than a contrail but not hard-edged, and almost as bright as Venus. The sky was otherwise absolutely clear, with no cloud. Through binoculars (7 x 50) he could see no sign of an aircraft or any other familiar object. He thought that the object was at an altitude of 30° (but observers usually exaggerate this).
The aerial phenomenon seen from Moffat on December 19, 1979 [© Bransby CLARKE]. Inserted is Steuart CAMPBELL's sketch of the phenomenon "made after further (x2) enlargement of the original photograph".
After fetching a camera he took three pictures in about 10 seconds [all three are similar to the one published here]. The camera was a Ricoh Auto-half (half-frame 35mm) with a 10mm lens of focal length 25mm. The shutter speed was 0.02 s, and the film was Ilford FP4 (ASA 200). He notes that although the object appears dark in the pictures it was certainly bright to the eye. It is in fact a "line of objects", as is made clearer by the sketch drawn from an enlargement of the photograph of Fig. 1. After about 5 minutes the object appeared to shrink as if receding. the outside temperature was 'cool', with no wind.
The object was also seen by witnesses at Hightae, 27km further south. Schoolboy Brian Patterson (13) described it as a shiny cigar-shaped object as bright as the Moon. It neither moved nor made any sound. Two schoolteachers (Elspeth Currie and Morag Johnstone) saw the object as they drove towards their school. Their descriptions agree with each other's, and with those of Clarke and Patterson, except that they saw a detached part on the left move towards the large object. At this point the phenomenon disappeared. Several other reports are known.
In order to identify the object an attempt was made to determine its exact altitude and azimuth. Since a half-frame negative is about 23.5 x 16.5mm, the camera's angles of view must be about 50° x 36°. With Clarke's help (this year) it was established that the object's azimuth must have been about 165°. The distant hills below the objet are about the same height as the camera (about 167 m OOD). Therefore, it can be calculated that the object's altitude is about 5°.
No visible astronomical object lay at that position at that time and date (as seen from Moffat). Venus was below the horizon and Mercury was at 8° altitude on an azimuth of 146° (just on the extreme left of the picture, but invisible). The sun was at 0° altitude on an azimuth of 134°. It has been suggested that the object was a patch of orographic Cu Fractus, but there are three objections to this idea. There are no mountains in that direction for over 90km, there was no wind, and the object is brighter if anything on the west not the east side.
It was noticed that the bearing of 165° leads directly across the Solway valley to Helvellyn (950m high), the second highest peak in the Cumberland Mountains, although at a distance of 95km. This suggested that the object was a mirage of Helvellyn, which, at that time of the year, must have been covered in snow. Furthermore, the mountain must have been well illuminated by the rising sun. Helvellyn's normal altitude from Moffat is about 0.5°. Therefore, if the object is a mirage of the mountain the image is elevated about 4.5°!
No temperature lapse data for the Solway valley are available (at any time), but with little wind and low overnight temperature an inversion in the valley is very probable. Such an inversion can produce a superior mirage, with elevation of the image proportional to the strength of the inversion. Not only is the image of a superior mirage elevated, it is enlarged, brightened and distorted. The image is also confined to a horizontal layer (the refracting layer), although it can spread in this layer. Over a distance of 95km the refracting layer must have been at least 190m thick.
Comment - A mirage of snowy Cumbrian peaks at an elevation of 5° would be very exceptional (notwithstanding the unproven assertion that Helvellyn "must have been" capped with snow in December). Alternative explanations would be a backlit/underlit irridescent cloud or contrail observed against a twilit sky, with the Sun just below the local horizon. Sea level sunrise around Moffat that morning would have been around 08:46 GMT.
It isn't clear, but we infer that CAMPBELL only saw a print enlargement, not an original negative. Perhaps the positive copy was printed at excessively high contrast to bring the object out from the background sky, so that one shadowed/denser part of the cloud/trail came out much darker than it had appeared to the eye?
Visually bright clouds that show up dark in photographs are not an uncommon to an experienced sky photographer. The effect is most noticeable for clouds that form on the lee wave side of mountains (the orographic Cu Fractus mentioned by CAMPBELL). With the Sun in the background, the ice crystals in the transparent edges of the clouds can reflect the sunlight so intensely that the clouds are visible only as patches or dots of a blinding yellow-white light with no further detail. When photographed with a short exposure time - the standard setting for daylight pictures -, the photos will only show the bright outline of the cloud patches with a dark nuclei where the cloud is more dense.
Visually bright clouds that show up dark in a photograph are not uncommon to an experienced sky photographer. The effect is most noticeable for contrails and (relatively) small ragged-edged Cumulus Fractus. When the Sun's position in the sky is close to that of the cloudlets, the sunlight will be reflected so intensely that the clouds are visible only as patches or dots of a blinding yellow-white light with no further detail. When photographed with a short exposure time, which is the standard setting for daylight pictures, the photos will only show the bright outline of the cloud with a dark nuclei where the cloud is more dense.
Two photos of a group of sunlit clouds taken by one of the authors in Monthey, Switzerland, in July 2012. The setting sun was just below the mountain and to the right of the clouds. The image on the left is a fair representation of what the scene looked like to the naked eye (because of the blinding intensity of the reflected light little more than uniformly-lit patches of light could be discerned). The image on the right is the same scene shot with a shorter exposure time. The main cloud now appears as a bright patch with a dark nuclei where the cloud is more dense. [© Wim VAN UTRECHT/CAELESTIA]
An explanation in terms of a string of cloudlets would also not conflict with the statements of schoolteachers CURRIE and JOHNSTONE who saw “a detached part on the left move towards the large object”. This is indeed consistent with the way these cloud strings constantly change size, making it look as if they continuously merge with neighbouring cloudlets then split up again. The witnesses being in a moving vehicle and viewing the objects from a continuously changing angle may have enhanced this illusion of one object moving closer to the other. Stueart CAMPBELL's objections to this idea are easily overruled: (a) there are plenty of mountains in the area that may have created standing waves in the direction the objects were seen, (b) although there may have been little or no wind at ground level, winds may have been strong at higher altitudes and (c) the fact that the object was “brighter if anything on the west not the east side” may have been the result of the cloud being more dense on the east side, thus obstructing the light of the Sun to reach the camera from that area of the cloud.
We contacted photographer Bransbey CLARKE in an attempt to obtain either the original negatives or high-quality digital scans of his photos. Unfortunately, our request was left unanswered.