It's Genuine: China Denies Copying NASA Moon Photo

Rumors have been circulating online that a photo released by the Chinese government and attributed to the country's first Moon probe is actually a copy of an image from the US defense department's Clementine probe of the mid-1990s.

"The first publicly released photo from China's Chang'e 1 Moon probe is genuine, but it has been modified to make it more pleasing to the eye," the chief scientist of China's lunar probe program has been forced to defend the authenticity of its first published photograph after internet moon-gazers suggested it might be a copy.

China has insisted the image it released really is from Chang'e 1. This is confirmed by a new analysis by Planetary Society blogger Emily Lakdawalla.

Clementine did image the part of the Moon that appears in the Chang'e 1 image. But the two images have differences that show the Chang'e 1 image is not merely a copy. As Lakdawalla points out, sunlight illuminates the scene from different angles in the two images, and the Chang'e 1 image reveals more detail (see images above - the top one is Chang'e 1, the bottom Clementine).

"My personal opinion, based upon the evidence I was able to dig up, is that the Chinese do have an orbiter at the Moon, and that it is producing really beautiful images that are a great improvement over Clementine," Lakdawalla writes.

But she also notes that the image released to the public is actually a composite made by stitching together 19 images, each of which shows a small part of the scene. The edges where the images were joined together have been smoothed to make them less apparent, Lakdawalla says.

The stitching together process also provides an explanation for an "extra" crater seen in the Chang'e 1 image (top right) that does not appear in the Clementine view of the same area (top left). The Chang'e 1 chief scientist has suggested that either Clementine's camera was not sensitive enough to see the crater or that it was gouged out by an impact after Clementine made its observations.

But Lakdawalla says flaws in the stitching-together process simply created an illusory duplicate of a real crater in the image. When she re-aligned the border between the images in the composite (bottom right), it became a close match to the Clementine image (bottom left), without the extra crater.

"However, because of the blending of the seams, this is not a product that should be used for scientific research - including looking for new craters," she adds. "Some of this problem should go away once the Chang'e team improves their knowledge of their spacecraft's orbit and of the shape of the Moon; with more precise positional information, their mosaics will automatically improve, having less obvious seams with smaller offsets."

The 3-dimensional view released by CNSA shows there is only one crater in that location:


Source: Newscientist
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