logo_jupiter_best.jpg (66101 bytes)

A fast-spinning giant world...

To observe or to photograph a full Jupiter rotation, an event that takes a little less than 10 hours, is a very interesting project that should be attempted in one of those long winter nights with clear and steady skies.

The straightforward approach for this task is to obtain a long series of images, and use it later on to build-up a time-lapse animation. However, to have access to 10 hours of constant good seeing is very rare indeed. In my case, another problem stood in the way. The "roof-top" observatory I use for imaging has not enough horizon to accommodate 10 hours of apparent rotation of the celestial sphere.

frames_best_jup_01.jpg (64134 bytes)

Fortunately, there are other ways of addressing the problem. I just used the four images presented above, picked-up from the data set obtained on three consecutive observation sessions (December 27-29, 2001). These images share common features near the planetary limb and a simple superimposition mosaic, shown below, confirms that the needed 360 degrees of longitude span were present.

superimpose_best_jup_01.jpg (102597 bytes)

Each of the original four Jupiter images was imported into IRIS software and, using its planetary cartography capabilities, the complete cylindrical projection depicted below was originated.

plani_best_jup_01.jpg (105605 bytes)

Also with IRIS software, the above planisphere was used to reconstitute 36 telescopic projections of the planet, each one differing 10 degrees in central meridian longitude. These projections were used as frames to build-up the time-lapse animation shown below. In a true time-scale consecutive frames are separated about 17 minutes, emphasizing the need to work quickly while drawing or photographing the planet.

rotation_movie_best_jupiter_01.gif (714832 bytes)

A grayscale version of this animation appeared as a "paper-movie" in the Abstract Book of the conference "EUROJOVE".

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© A.Cidadão