National UFO Reporting Center Case Brief
July 23, 2002 - West Hills, California

NUFORC Home Page


Three family members witnessed large extending chevron formation of lights traveling silently north to south at 10:05 pm 23rd July 2002, looking East from back yard patio in West Hills, California.

Conditions at the time

Clear sky, Moon rising (95% full), Stars visible at elevations above about 40 degrees. 

Event description 

At approximately 10:05 pm on the evening of the 23rd July 2002, primary observer sees what appears to be single white light appear in north east view: (definite perceived diameter, indistinct edges, slightly diffuse, brightness similar to 1st magnitude star or small plane headlight at a few miles range). Movement directly north to south, apparent angular velocity similar to small plane at same brightness-distance; similar to 90-120 minute polar-orbit satellite. Observer became interested as no additional navigation lights seen, no engine noise audible, light several tens of degrees below Earth umbra (initially considered it to be a satellite).

Observer now joined by wife after strangeness of the event became apparent. As watched, the white light was joined first by one, then over several seconds, many other lights, these being very bright red and slowly-flashing point-sources. After about a minute, these red lights, which appeared as they developed to grow further away from the white light, made a chevron shape, the white light leading, with the red lights tailing at almost exactly 45 degrees backwards. By the time the development had stopped, there were approximately five red lights "below" the line of motion, and two red lights "above" the line of motion and the white light.

The event was watched for about 2 minutes, with the shape of the formation (angle of the chevron) unchanging, as was the mean velocity of the north-south motion of the ensemble. The elevation of the object throughout was a straight line about 30 degrees above the horizon (the elevation below 20 degrees blocked by adjacent buildings and trees). No engine sound was heard throughout the event, even though small planes at the same velocity-white light brightness are regularly heard from this location.

About half way through the event, the observer called his son to observe. His son had a medium-quality set of small binoculars available (8x21mm). The primary observer played these over the object, but could discern no additional navigation or "wing" lights, nor could any structure be seen between the lights, even though as the object moved to the south, before disappearing, it passed beneath the almost full bright Moon. (Previous and later observations of small planes with the same binoculars showed distinct wing shape illuminated by both Moon and ground-light scatter, as well as clear red/green nav lights as required by FAA). From observer's reference point, the maximum angular dimension subtended by the object was approximately three Moon diameters (or about 1.5 degrees) "tip" to "tip". Shortly before the object went out of sight, it appeared to develop an additional lobe in the leading white light, as seen from "behind". There was no occlusion of any of the lights even as the aspect angle must have been changing, again indicating lack of opaque structure. The object finally disappeared below buildings to the south east. There were no other aircraft in the vicinity during the two minutes of passage, although about 15 minutes after the event, two high-flying single-engine military-style jets flew very fast in the same north-south track (seen clearly in binoculars, including wings and navigation lights). The following drawing illustrates the development and passage from north east to south east.


Analysis 1

1) Another reporting observer was apparently located in Reseda, stating that the object went directly over him. Knowing the approximate distance between this observer's house and Reseda, this information was used to develop a geometric triangulation of the event. Knowing the difficulty of exact estimation, an uncertainty analysis has been applied to the dimensions involved. The following assumption ranges have been computed: Elevation angle 20 to 30 degrees; horizontal range (West Hills to Reseda) 3 to 5 miles; Subtended angle of the object 2 to 3 Moon diameters.

Based on these assumptions, observer calculates :

(a) The mean altitude above sea level of the object to be 13,200 ft (after taking observer's GPS elevation of 900 ft into account). (Possible range 7,000 to 16,000 ft altitude taking uncertainties into acount);

(b) Mean size of the object (tip to tip) 169 yards (Possible range 98 to 270 yards).

Analysis 2

Identical observations were received ranging from somewhere in Sequoia national park (campers), to Avalon area on Catalina island. A more detailed report came in from Tehachapi, followed by more (Valencia, Santa Clarita, Santa Monica, Marina Del Rey), all indicating the same object, and all with timings that indicate that the object travelled in a direct unwavering approximate north to south line. The reported timing of the observations indicate that the approximate linear distance between Tehachapi and Avalon ( 130 miles) was traversed in about 40 minutes, giving a linear velocity of about 190 mph, which is not inconsistent with the observation that the object appeared to be travelling at the same approximate ANGULAR speed as a small plane (which are normally a little lower and a little slower). Possible explanations: In the 40+ years of astronomical and aeronautical observations carried out by this primary observer, nothing like this has ever been seen before. The apparent geometrical rigidity and size of the formation implied significant structure, not observed at all. The silent passage of the object cannot be explained by normal engines experienced by the observer, and yet the velocity is inconsistent with any known dirigible. Anyone who has seen a small plane towing a sign knows that in the airstream, the trail flaps out linearly backwards, not rigidly in chevron formation. The thing that mimics the observation (but impossibly) is a very high-flying flock of Canada geese with super-bright red navigation beacons tied to their tails. If the observer were to try to mimic the data (as for a hoax) with a construction needed to match the observation, he would conceive of a relatively high-flying private plane or helicopter, with normal nav lights extiguished, reeling out a string of bright "radio-tower" red beacons on a cable whose weight is supported by aerofoils to maintain altitude (avoiding catenary-shaped drag). Such a venture would be illegal (no nav lights, flying across commercial airspace at right angles to heavy traffic routes into Burbank airport), and moreover extremely expensive to execute.

(i) The only man-made structure known to the observer that could mimic the size, altitude and velocity of the observation is a possible variant of the unmanned AeroVironment Helios electric airplane, implemented with translucent wing material. However, published data on these type of craft so far have shown only linear wings (not chevron), and a night-flying version of this type of craft, to be fitted with fuel cells, and presumably navigation lights, for night-time operation (instead of the purely solar-powered current models), is not predicted for investigatory development until next year sometime. It could of course be that the military is advancing such development in light of the current international situation, but countering this is the unlikelihood of such a developmental craft being "exhibited" openly over the San Fernando valley at prime time on a clear summer evening !

(ii) For those escapist afficionados, it would similarly strike one as very embarrassing for any self-respecting "visitor" (should they possibly exist) to choose to outfit his vehicle with gaudy flashing super-bright red beacons and flaunt his presence so boringly to a jaded citizenry. Observer's conclusion: Definitely an "Unidentified Flying Object", and very annoying for the observer that who can't instantaneously generate a practical design to mimic the data at hand.

Observer experience: Masters Degree in Physics; Working in aerospace engineering for 30 years; Member of an amateur astronomical society for 35 years; regular amateur astronomical observation in same West Hills location for more than 15 years, including observations of many natural (meteors, comets etc.) and man-made objects (satellites, rocket stages etc.).