Comet 67P/C-G in color

Comet 67P/C-G in color

You might not believe it, but the image on the right is the first color image taken by Rosetta of Comet 67P/C-G. (Click on the link to see a full image.)

To create an image revealing 67P’s “true” colours, the scientists superposed images taken sequentially through filters centred on red, green, and blue wavelengths. However, as the comet rotated and Rosetta moved during this sequence, the three images are slightly shifted with respect to each other, and are taken from slightly different observing perspectives. Painstaking work is needed to superimpose the images accurately, which is one reason it has taken so long to come up with the first meaningful colour image of 67P/C-G.

As you can see, there really isn’t much color there. Moreover, the comet is so coal-dark that they had to brighten the images to bring out any detail.

In color from Mercury

The Messenger spacecraft has now been in orbit around Mercury since the end of March, almost four months. During that time the probe has sent back many fascinating images, showcasing a hot, alien planet whose surface was formed by impacts, volcanic activity, and some processes that no one as yet understands.

Most of the released images, however, have been in black and white, which at first glance makes one think that Mercury is not unlike the Moon. This week the Messenger team released a color image, demonstrated clearly how false this assumption is. The image below shows two very different craters, a dark-haloed crater named Basho at the bottom left of the image, and a very bright crater, Kalidasa crater, near the top left. On the right of the image is a dark haloed Tolstoj basin. For an uncropped full resolution version go here.

color image from Mercury
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