On July 3rd, 2006, there will be a spectacular flyby of the near-Earth Apollo asteroid 2004 XP14. Like the flyby of 2002 NY40 in 2002, 2004 XP14 will amaze visual observers with incredible speed visible in medium size telescopes. Near close approach is around 4:44m UT July 3, this 600-meter/yard diameter asteroid Passes only 268,873 miles from the Earth, only 1.1 times the distance to the moon away. Peaking at visual magnitude 11.1 four hours later, users of telescopes of 6 inches (15cm) or larger can enjoy observing a rare celestial treat. At time of close approach, 2004 XP14 races along at 8.323 degrees per hour, or a mean lunar diameter every four minutes! Such a rapid speed results in direct motion becoming visible, second by second. Just as naked eye Earth satellites are seen crossing the sky, 2004 XP14 will both amaze and challenge the observer, both visually and those taking images.
Initial observations of the Asteroid by amateurs in America have reported that the asteroid was over a magnitude fainter than the predicted 11th magnitude.
The orbital elements of 2004XP14 show that it will return on July 4 at less than 0.03511AU, and again in July 5th 2102 at 0.04152 AU, Last nights passing was the closest at only 0.00512 AU.
As yet it is too early to report on observations by the larger observatories that were following the asteroid.
Extensive observations are planned with the NASA 70-m radar at Goldstone, California, which is part of the NASA Deep Space communications network. It is anticipated that these radar studies will yield detailed images of the asteroid, as well as highly precise values for its orbit and spin state. Many NEAs have recently been found to have satellites, and the presence of a satellite will also be looked for with the radar.
This close pass by such a large asteroid has little historical precedent, but calculations show that a NEA this large comes this close about once per decade on the average. However, similar close passes in the past were not observed, since it is only in the past decade that the Spaceguard Survey has begun to inventory NEAs in this size range.
To help sky watchers locate the asteroid, dubbed 2004 XP14, Sky and telescope have kindly prepared three detailed, overlapping star maps: Chart A, Chart B, and Chart C. Each is an Adobe PDF file that you can print for use at the telescope.
But for most people these will be useless -- this rock is really travelling - and its faint. its heading up from below, zipping past the planet, and up towards draco. Those in the southern hemispheres or darker skies, and with a fast motor on their telescopes, will have a better chance. But i suppose you could try the "Ambush technique" - just watch a bit of the sky where you know where it'll cross...
2004 XP14 will approach Earth ten more times during the next 82 years, but this weekend's will be by far, the closest. On July 4, 2061, it will make its next closest approach to Earth: 5.04 million km away.
Currently the next very close approach of a Potentially Hazardous Near Earth Asteroid will be 2005 YU55 as it passes at a distance of 158,000 kms from the Earth on November 8, 2011. That distance may be only be half the distance of this weekend close encounter with 2004 XP14.