Asteroid 2004 BL86 is on track to pass Earth on Monday, Jan. 26, resulting in the closest flyby of a space rock until 2027 when 1999 AN10 makes its trip close to the planet. NASA's Near Earth Object Program released updated charts on the flyby, chronicling the path 2004 BL86 will be taking as it skims by.
Three charts have been made available. The first one offers a view that's nearly edge-on to Earth's orbit, although the nearly circular orbit of the moon is "highly foreshortened." According to the first chart, the asteroid is moving from south to north, traversing Earth's orbit from below. Times were also indicated (Universal Time) to guide astronomers accordingly, with the closest approach (about 3.1 times the distance between the Earth and the moon or 750,000 miles) pegged at around 11:19 EST or 16:19 UTC.
The second chart is a star chart tracking 2004 BL86 through an equatorial coordinate grid. As the asteroid moves through stars, its location is pinned at four-hour intervals beginning Jan. 26 and running through Jan. 28. Again, Universal Time is used to indicate times. For EST, subtract five hours. For CST, six hours. For PST, eight hours. On Jan. 26, the asteroid 2004 BL86 will be passing within 11 degrees of Jupiter, which is highly visible in the evening sky in the east.
The third chart shows the asteroid's two-day track relative to 9:00 p.m. on a local horizon, seen from various spots in contiguous United States. Cardinal directions are provided at the bottom of the chart to clearly show 2004 BL86 passing close to Jupiter. All times used on the chart are, again, in Universal Time.
The asteroid 2004 BL86 will be roughly 1,500 feet in size. The flyby poses no threat to the planet, but astronomers are keen on observing the event because it's the closest that a relatively large space rock would be flying by Earth.
NASA, for one, will be relying on microwaves to observe the asteroid and will be taking as many images as possible of 2004 BL86 as it makes its way to Earth. Radar-generated images should be received by the agency a day after the flyby.
Amateur astronomers can observe the event on Monday with telescopes and binoculars trained at the constellation Cancer. With a visual magnitude of 9, the asteroid should be visible like a faint star at apertures of at least 10 cm.
