Icelander publishes new image from Ganymede, Jupiter's largest moon

This mosaic of Ganymede was made using 45 images obtained …

This mosaic of Ganymede was made using 45 images obtained by Voyager 1 on March 5, 1979 over a period of about 2 hours. The image is in approximate true colours. Image by Björn Jónsson

His latest project, Ganymede was made using 45 images obtained by Voyager 1 on March 5, 1979 over a period of about 2 hours. During these two hours Voyager 1's distance from Ganymede dropped from 305,000 to 180,000 km.

The greatest problem Jónsson encountered when making the mosaic of Ganymede was that some of the source images were smeared. In a blog post on website Unmanned Spacflight.com he explains, "This happened because the intense radiation in Jupiter's magnetosphere affected Voyager 1's computers and clock. As a result some of the images were taken when the instrument scan platform was moving. It's difficult to make a full color global mosaic without using some of these smeared images.“

Following feedback he received from the image processing community, Jónsson managed to successfully deconvolve the images, making it possible to use them.

The maps created by Jónsson are in approximate true colour. The seventeen frames were each created using three images taken in different spectra of light. However, says Jónsson, not quite all the source images were in colour. In those cases he was forced to "cheat" and apply his own colouring to small areas. 

Speaking to mbl.is yesterday, Jónsson says that he's now working on a rendering of Callisto, Jupiter's second largest moon. 

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