Solarized image from frame-grab of object near the Moon.

   Subject: U092196  to avi file link During routine scans of the lunar surface with the 16" scope equipped with a CCD camera, The Lunascan Project team tracked an unknown object near the SE lunar limb for twenty seconds. The Moon was under HPS Mode (High-Power Scanning) at 400 power, putting the surface at less than 600 miles. The scope/camera system had been in manual control to the limb, then used the Earth's rotation to slowly scan to the terminator. Once in the darkness of the lunar night the system was manually pulled back to the limb for another scan, each slice slightly different.

At the BOS (Beginning Of Session, 7:00 PM) the numbers for auto track had been routinely punched into the DOB Driver II computer. However, since the auto-track mode causes short L-shaped jerky movements during taping, the computer is placed in Pan which is manual. As team members watched the outside monitor, they noticed in the blackness of space to the right of the Moon, a very brief bright speck. Due to deterioration of the weather the session was terminated at 10:00 PM and the datatapes rewound.

At 00H26m CUT, queued on the tape, was the object. At first glance it looked somewhat like a satellite of Jupiter. In fact, the object was about that size. But no star, let alone any moon of Jupiter, had ever survived the glare of the lunar limb. Not once during the last year and 23 other sessions had the scope picked up anything that close. Immediately the facility's main computer was booted up and EZ Cosmos was loaded. The status screen read the current date and time. The exact time of the incident was punched in and the sky chart was put onscreen. Upon zooming in on the Moon and sky sector, to see if there was a bright star or planet nearby that could account for the object, it was determined that nothing conspicuous was anywhere near the Moon. Before the end of the hour a frame-grabbed image had been placed on The Lunascan Project web site. By Monday afternoon a complete report was filed.

Lan Fleming: Trajectories could be envisioned that could make such an object appear stationary relative to the moon for 20 seconds to an Earth-based observer, but the data now appears to be more in favor of an object in lunar orbit. A maximum speed of about 3400mph for something in lunar orbit translates into an angular velocity as viewed from Earth of .0002 degrees per second. In the 20 second time span in which the object was in view, that would produce an angular displacement relative to the moon of only .004 degrees, or about 6% of the .06 degree FOV. But this is only for objects orbiting near the surface of the moon. The speed decreases rapidly with altitude, which would make the motion increasingly difficult to detect. As for non-orbiting meteoroids, trajectories could again be envisioned that would hide the true motion of the object in the lunar reference frame from an Earth-based observer. But the set of possible paths that would do this is going to be larger for a slow-moving orbiter than for a faster-moving non-orbiter. This seems to favor the interpretation of the object as being a lunar orbiter. It is also unlikely that astronomers would miss a 2-mile long asteroid that got this close to Earth! Lan Fleming: The lack of apparent motion relative to the moon could be most easily explained by an orbiter. While the low-altitude orbital speed at the moon is such that an object would move a maximum distance of 5% of the telescope FOV in the 20-second observation time, there are two points in a lunar orbit at which the object would appear to be motionless relative to the moon as observed from Earth: the point in the orbit where the object is moving directly toward the Earth and the point where it is moving directly away. The two points would be close to the positions where the object was farthest from the moon's limb and are the only places where the object would likely be seen at all. Assuming the object was at the apparent 45-mile altitude above the moon in the video image and had a two-hour orbital period, there would only be a period of 11 minutes between when the object emerged from behind the moon and when it moved across the moon's disk where it would be lost in the direct moon light. Within that 11-minute time span, the object might be visible for only a few seconds at its farthest distance from the moon's limb before it became lost in the bright moonlight diffused though the Earth's atmosphere close to the limb. (The image that Francis has on his web site shows this atmospheric haze around the moon.) Such an object might therefore appear suddenly and disappear just as suddenly after the 20-second period that Mr. Ridge observed the object. That would make an object orbiting the moon a more likely explanation than an asteroid travelling straight toward Earth. The only problem with the orbiter hypothesis is that the chances of the moon capturing an asteroid seem to be close to nil. It's low gravitation would make captures rare, and the orbit would quickly degrade due to the the gravitional anomalies associated with mascons. The estimate I've heard is that any orbiting object will either escape the moon or impact it within about a year.

Lan Fleming: I wrote: there are two points in a lunar orbit at which the object would appear to be motionless relative to the moon as observed from Earth: the point in the orbit where the object is moving directly toward the Earth and the point where it is moving directly away. The two points would be close to the positions where the object was farthest from the moon's limb and are the only places where the object would likely be seen at all. I should have qualified that a bit. This would only apply for an object in a lunar orbit if the orbital plane were perpendicular to the the plane of the telescope field of view. If the orbital plane were instead parallel to the FOV plane, the object would appear to be circling the moon at more-or-less constant altitude and speed. The orbital plane would probably be somewhere between the two extremes. However, most asteroids travel in the ecliptic plane, so if one happened to get captured by the moon, its orbital plane would be in the ecliptic. Since the ecliptic is very nearly perpendicular to the plane of a telescope FOV, the orbiting object would appear nearly motionless from Earth at its maximum distance from the moon's limb. A second possibility might be some tank on some probe venting for some reason. The resulting gas cloud could be visible from Earth before it disappeared after a matter of seconds. And, in fact, the report reminds me the cloud people saw when Apollo 13's tank gave way -- a spot of light that was gone again in seconds. (That one was easily visible to the naked eye, I think I remember ... but it was 100,000 miles away, not 250,000 miles.)

One-hour video documentary with report and footage on U092196 available. Shipped Priority Mail. Send money order for $23 to:

The Lunascan Project
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