ASTRO: 2005 YU55 Nearly missed it

This was a nasty. Minor Planet Center's orbital elements weren't right
as an hour of fruitless hunting pointed out to me. JPL's site was
unreachable due to traffic. When I'd get in it would crash and I'd have
to start over. Finally about 3 hours after closest approach I got some
good elements from the JPL site. But then the dang rock was really
hauling at about 10" of arc per second of time! It had slowed to about
8" by the time I managed to get it centered. While the mount will track
a moving object it takes some time to do this. So you have to lead the
object with the camera and then input the tracking rates and hope by the
time you do it isn't off the screen. First tries it was nearly off. Took
lots of trial and error to move it to the center as each slew would turn
off the tracking. The rate was changing so fast by the time I'd input
the values they were wrong! I had to lead those as well. Finally I
managed to get usable data.

This is a single 15 second image. Image scale is 1.5" of arc per pixel.
Asteroid is nice and round so the mount was working fine but the stars
are moving so fast you see the atmosphere "twinkle" in their trails!
Stacking was out of the question as the number of stars would be too great.

I should be able to put a movie together out of the 20 or so frames I
grabbed. With such short exposures seeing changed quite a bit each
frame. It will be an "interesting" task to make the movie. Until then
this will have to do.

Rick
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".