UPDATE 20th September 2016. The first two gifs (dubbed 1a 1b) use a post perihelion photo from a more recent NAVCAM archive release. Annoted gifs using other photos follow these first two.
Gifs 1a (slow) and 1b (fast):
The perspective along the line of the boulder movement changes between by around 15° (estimated maximum) between the before and after images in 1a and 1b. For the purposes of constructing the gif, the two large boulders below the Anuket crack were aligned by rotating and cropping one of the photos. This introduces a potential maximum error along the line of these two fiduciary points of 3.5% (cosine 15°) between the two component images. This line between the two boulders is orientated in the same direction as the boulder movement in question. This therefore introduces a potential maximum error along the line of the boulder movement of the same amount, 3.5%. The boulder itself moves by over 100% in relation to its two companions at the base of the triangle of boulders. In other words, it more than doubles its distance from the two base boulders and that large distance that it moved is subject to a maximum 3.5% systemic error. So there is a relatively insignificant error of 3.5% in relation to the large boulder movement distance.
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Gifs 1 and 2 – slow and fast. Red boulder moves much more than small movements in surroundings.
Gifs 3 and 4- as above but these include the big crack in brown in order to show the slight viewpoint perspective change. This is why all parts of the images jump a bit but nothing like as much as for the red boulder.
This Part is a follow-on from Part 55. These gifs are compelling but the unequivocal evidence for red boulder movement is in that part.
Copyright ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0
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ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DyASP/IDA/
All dotted annotations by Andrew Cooper