Asteroid 2004BL86, 26 January 2015
Asteroid 2004BL86, officially classified as a Near Earth Object (NEO), was discovered on 30 January 2004 by a telescope of the Lincoln Near-Earth Asteroid Research (LINEAR) survey in White Sands, New Mexico. On 26 January 2015, it passed within 1.2 million km of the Earth (roughly three times the distance from Earth to the Moon). Astronomers estimate that the asteroid is about 0.5 km in diameter and that no other asteroid of comparable size will approach so close to the Earth until the object 1999AN10 in 2027.
At its closest approach to Earth, 2004BL86 appeared as a magnitude 9.0 object moving through the sky at a speed of 2.5° per hour. It thus became an interesting object for amateurs to observe.
I used a William Optics Megrez 90 APO refractor at F5.2 with low pass filter together with a Canon 60Da camera at ISO 1000 to capture a sequence of images of 2004BL86. The images are assembled below as follows for presentation. On the LHS is a movie (.mp4 and .ogv formats) showing a sequence of 60 images, each of 60 seconds duration, spanning the period 21:50:44 - 22:52:42 UT. On the RHS is a stack of the 60 frames (.jpg format).
The track of 2004BL86 is from bottom right to top left. Running from top right to top left is the track of asteroid 105 Artemis, entering eclipse and becoming invisible. The track from lower right to lower left is created by an unidentified geostationary object.