The potentially dangerous, recently discovered, Near Earth Asteroid, 2013 QR1 taken by me on August 25, 2013 at 3:52 through 4:26 UT in one minute frames. This was one day before closest approach. I was under a thunderstorm when it was closest in dark skies. The asteroid was estimated at 250 meters across and was moving about 1.57 minutes of arc per minute of time. The telescope was tracking on the orbital motion of the asteroid causing the stars to appear to move by the asteroid. North is up, west to the right.

We are the target in a shooting gallery with small asteroids the bullets. Earlier this month it was a well known near-Earth asteroid 2003 DZ15, about 150 meters in diameter that came by at about 2.2 million miles when I caught it. It is 250 meters wide (bringing out the big guns?) 2013 QR1 (discovered August 16 UT) caught at about 2.3 million miles though it came within 1.8 million miles the next day. It was nearly as distant that next night as the first night but we had a raging thunderstorm and it was too low in the southwest in any case. While slightly further away it was moving faster than 2003 DZ15. Fortunately, its larger size made it brighter allowing me to use one minute exposures rather than 2 so the star trails aren't as long as they could have been. The animation uses 30 of the 80 frames I took that night. Earlier ones were hurt by poor seeing, later ones by the moon. The frames used were taken on August 25, 2013 starting at 3:52 UT and ending at 4:26 UT. The extra 4 minutes are due to the time needed to download each frame to the computer. While I took 10 frames after this clouds got thicker, the moon brighter and I just couldn't compensate after that. Even so, the asteroid will vary somewhat in brightness due to the various thickness of the clouds I was working through. Later they went away but the moon was so bright I just couldn't pull the asteroid through the moonlight. Due to the poor conditions, I didn't get a magnitude estimate. It was likely about 16.1 or a bit fainter but don't quote me on that!

When I started the imaging run of the 80 frames the asteroid was moving at 1.47 minutes of arc per minute of time. That is the rate the computer used to compensate for the asteroid's motion and was correct. By the end of the 30 frames used it was moving at 1.58 minutes of arc per minute of time. Like a dummy, I didn't reset this rate so the asteroid does drift a bit during the 30 minutes.

North is at the top and west to the right. For some reason, I rotated the 2003 DZ15 image so it appears to move the opposite direction. Both were moving to the west. The earlier one was moving north while this one was moving south. Image scale is about 1.5" per pixel. I say about as the movie maker changed the scale somewhat and I didn't try to determine what the difference was. 2003 DZ15 was at 3" per pixel.