ASTRO: NEO (153958) 2002 AM31

(153958) 2002 AM31 is a NEO (Near Earth Asteroid) that got a lot of
print a few days ago. It passed "close" to earth on July 22.99. That
was daylight here and cloudy all night. The following night about 29
hours after closest approach it was only 1.2% further away or about
3,363,000 miles. Conditions still weren't great. I took 40 minutes of
data of which the last 20 were usable though the first few frames were
iffy and needed some work due to clouds. I made the 20 frames into a
GIF animation each frame 1 minute long covering 20 minutes real time so
you can see it is really moving. Each frame is one minute so the motion
is 200 times actual speed. For some reason I count only 19 frames in
the animation. I seem to have lost the first one or can't count fast
enough.

Images taken while the Paramount ME was tracking the predicted orbital
path. There seems to be a slow drift north and I found it was not
exactly where the elements I used (several days old) predicted. Likely
due to changes in the orbit due to the close passage. Still it tracked
the asteroid well enough. I could have aligned the images but time was
short so they were not aligned in any way. This is just the raw data
from the camera using a one quarter frame binned 3x3 using a simple
linear histogram stretch. Only processing was dark subtraction. No
flats were taken as not needed with that simple processing. Image scale
would be 1.5" per pixel. Taken with my ordinary equipment, 14" LX200R @
f/10 and STL-11000XM. Each frame processed to about the same star and
background intensity. Difficult due to rapidly changing conditions.

Now in Camelopardalis it is still well positioned for those wanting to
give it a try. Due to phase angle it was brightest (about magnitude
13.8) on the 19th (UT) and has been getting fainter due to phase angle
changes. Tonight (early morning) (July 26.4 UT) it is projected to be
magnitude 15.9. It would be more challenging but with a wide field so
the asteroid moves more slowly or with a mount that can track the
asteroid it should be visible for a few more days.

Slooh's coverage (40 minute video) of the "event" is at:
http://www.youtube.com/watch?v=JG9YzKlFDbo

Or you can watch my 7 second video below. It will take longer than
that to load for those on dial up unfortunately. It's a bit less than 1
megabyte so bigger than a normal image. Therefore I am just giving the
link.

http://www.prairieastronomyclub.org/..._2002_AM31.gif

I've attached a single frame from the animation

Rick
--
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