2004 BL86 Passes By

Asteroid 2004 BL86 is not small, it is large enough for astronomers to take notice as it passed near the earth yesterday at a close, but safe distance of 745,000 miles. Numerous telescopes were trained on this object as it passed by, including a deep space radar at Goldstone that confirmed that the asteroid is about 1,100 feet in diameter. They did get a surprise as well, 2004 BL86 has a small moon.

Close approach was earlier in the day, thus it was some hours after that I was able to photograph the asteroid from Hawaii. The most difficult part in taking the photo is locating the object. An asteroid this close by will move across the sky very quickly. To locate the asteroid I used a high precision ephemeris generated by the JPL Horizons Database with time intervals of every half hour. This was necessary as the asteroid was moving several degrees each hour. If I used coordinates even an hour off it would have been out of the frame. It took half an hour of hunting, comparing frames taken a couple minutes apart.

Below is the streak created as the asteroid moves over the course of an eight minute exposure…

2004 BL86
Asteroid 2004 BL86 just after close approach on January 26, 2015

Author: Andrew

An electrical engineer, amateur astronomer, and diver, living and working on Mauna Kea, Hawai'i.

One thought on “2004 BL86 Passes By”

  1. cool dude proud of u to capture it
    I tried to see it live but there server was down 🙁

    gave up and then Slooth had it in irtf ‘s finder
    alohas and congrats

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