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CNSA via Reuters / Xinhua

A detail from China’s Chang’e lunar orbiter shows cratered terrain on the moon. A yellow circle has been added to highlight craters that show evidence of botched photo retouching.

Some dogged sleuthing by a fellow space blogger has tracked down the truth behind the controversial first photo from China’s moon orbiter.

In the week since the picture was released amid much fanfare in Beijing, there have been widespread rumors that the photo was a fake, copied from an old picture collected by a U.S. space probe.

The good news for the Chinese is that Planetary Society blogger Emily Lakdawalla’s clears them of outright fakery. The bad news is, she found evidence that the photo was badly retouched for public release.

Lakdawalla’s explanation would be embarrassing for Beijing, but it makes the most sense as the solution to this week’s moon photo mystery.

Lakdawalla began her investigation by plowing through databases of lunar imagery and dredging up a U.S.-produced picture for comparison. It’s not a NASA picture, as reported by the rumor mill. Instead, it’s one of the tens of thousands of pictures taken by the Pentagon’s Clementine lunar mapping orbiter back in 1994.

The photo from China’s Chang’e 1 orbiter is clearly a higher-resolution view, with sunlight streaming from the northwest rather than the north.

"So the notion that China faked their lunar photo can be put to rest. (What is it about the moon and conspiracy theories, anyway?)," Lakdawalla wrote. "At least it certainly isn’t a copy of the Clementine image; and it’s certainly not a Lunar Orbiter image, either."

Case closed? Not quite.

Lakdawalla found that a mistake was apparently made in stitching together the 19 strips of imagery to produce the finished picture - and that Chinese officials unknowingly pointed out that mistake as they defended the photo’s veracity.

NASA / DOD / CAST

The Planetary Society’s Emily Lakdawalla compared Clementine imagery of the crater, at left, with Chang’e imagery at right.

The mission’s chief scientist, Ouyang Ziyuan, told the Beijing News that a new crater had been spotted on the Chang’e imagery - a crater that didn’t appear on the U.S. imagery. Lakdawalla determined that crater in question it wasn’t exactly new - instead, it appeared to be a crater that had been moved from one spot on the picture to another spot slightly south.

Lakdawalla, who knows her way around spacecraft photo databases as well as photo-retouching tools, hit upon the likeliest explanation for the gaffe. Often, surface features that show up on two strips of data have to be manually corrected to produce the finished image, due to subtle changes in perspective.

"You know that there should have been seams in that image, and I just did not look for them carefully at the time," Lakdawalla told me today.

She said the Chinese must have blended together the seams between the strips - misplacing the crater. The picture may be pretty, but it’s pretty much useless as a scientific product, Lakdawalla said.

The detective work came in for kudos from other space mythbusters. "Go check out her really amazing sleuthing," said Bad Astronomy blogger Phil Plait. "This is how it’s done, folks. Case closed!"

NBC News space analyst James Oberg, who has had his own experience with moon-hoax controversies, also saluted Lakdawalla’s efforts. Even though the Chinese insist that the first picture from Chang’e is scientifically accurate, Oberg said he expected the Chinese to "be forced to backtrack a bit" once they see the full evidence.

"This isn’t the first time that photo problems have created illusory ‘moon features,’" Oberg wrote in an e-mail. "The very first Soviet moon photo probe, Luna 3 in 1959, sent back images of the back side that included a view of what Moscow grandiosely called ‘the Soviet Mountains,’ stretching for hundreds of miles. It turned out to be an emulsion smear on the negative."

"For a ‘dead world,’ the moon sure continues to offer surprises to explorers," Oberg said, "even if many of the ’surprises’ are self-induced flaws in the exploration process!"

嫦娥一号公布的图片被网友证实拼接失误

2007年11月2日下午，一位名为“美的眼睛”的网友在上海网上天文台社区发表了一则题为《疑问：欧阳自远说的嫦娥月照上的新撞击坑》的帖子。

　　今天欧阳院士说出来我有点惊讶，但是图上确实很明显。刚才我又把我们的图和 GoogleMoon仔细比了一下，发现“新撞击坑”的说法问题很大。最可能是问题出在图片拼接环节。很可能有一方把图拼叉了。我去嫦娥版新发个帖子大家好好看看。

　　我的 WorldWind坏了下不了清晰的月面图，谁有的拿来也比一比。

　　局部：箭头所指是欧阳先生指出的新坑，直径约3km

　　疑问坑的局部

　　根据地形特征，从左向右推算（黄线），再从右向左推算（红线），结果发现走到中间错了位，嫦娥的两个坑对应的其实就是Google的一个坑。蓝线我怀疑是局部拼接线。!

　　到底是嫦娥把一个坑错位成两个坑，还是美国人把两个坑错位成了一个坑，倒是都有可能。唯最不可能就是“新撞击坑”之说。

　　请大家讨论，毕竟我的 GoogleMoon月图也不够清晰，如果大家同意我的观点，请有机会时向欧阳院士转述，或请他来直接看帖。

　　进一步证据表明更可能是嫦娥图像处理人员的失误，而不是 NASA。

　　看问题坑的南面有一个条索状物，在嫦娥图片中一劈为二了（红色箭头所指）。注意参照黄色箭头所指的地标。^

　　在这幅三维图里那个小坑的拼接是正确的：

　　只要是处理中的无心之失，那就只是一点小错误，哪里值得？

　　今天有时间又仔细看了一下，找到了完整的错位拼接线，长约一百多公里，错位约3公里半。倾向于是无心之失：

　　错位拼接线的大体位置：

网友skyhobby说：楼主太牛了.果然是嫦娥一号图像拼接失误.我用photoshop作了一个简单的移位,就和google moon上的图像一样了

 
 
Sources - 来源:
Moon photo mystery solved
嫦娥一号公布的图片被网友证实拼接失误