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"Toutatis" Observed with the ESO New Technology Telescope

29 Gennaio 1993

This photo is a composite of five exposures of Minor Planet no.~4179, also known as Toutatis, obtained with the 3.5-m ESO New Technology Telescope on December 21, 1992, by ESO-astronomer Jesper Storm. At this time, Toutatis was about 13 million km from the Earth, i.e. 33 times more distant than the Moon. On December 8, this Minor Planet passed within 3.6 million km from the Earth, but at that time it was not possible to observe it with ground-based optical telescopes, because it was situated between the Earth and the Sun. However, very good radar images were obtained which showed thecratered surface of the object.

The unusually rapid motion of Toutatis, caused by its small distance from the Earth, is well illustrated on the photo. The first exposure (at the arrow) was obtained at 8:05 UT on the indicated date and lasted 120 seconds; the next (in the direction towards the upper right) lasted 30 seconds at 8:10 UT; a 5 second exposure was then made at 8:15 UT, and the last two (near the right edge of the photo) at 8:59 UT and 9:01 UT also lasted 5 seconds each.  During this one-hour interval, Toutatis moved a distance of more than 3 arcmin in the sky.  In fact, the first (120 second) image is clearly trailed in the direction of the motion.

On this day, the magnitude of Toutatis was about 11. The bright stars in the field have magnitudes 8 (above) and 10 (below).

The scale of the photo is 12.5 arcsecond/cm. North is up and East is to the left.

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