Asteroid flyby observed

Hello:
Last night a number of us observed the NEA starting around 11:40 pm HST (9:40 UT) from 9,300 ft on Mauna Kea. It was quite easy to see in a 12.5", but it couldn't be found in a 80mm refractor. At the time, it was about 20 degrees above the horizon. The speed with which it was moving was quite remarkable. When I was trying to find it, if I couldn't find it after looking around its field, I had to check the S&T chart to see where it should be now, and then look there. Eventually, I found a bright star it was going to pass in a few minutes and waited. Right on que, it came by and after that I was able to follow the asteroid. You know how, when you have a dobsonian at a star party, you need to recenter the target after each person looks? That's what I had to do, even though the scope was tracking! Its motion was quite apparent, especially when it passed by another star, which frequently happened. It was expected to get as bright as 11th magnitude, and I'd say that it looked a bit fainter than that. Given that we saw it after closest approach, and at high airmass, it makes sense. I don't know how long we were following it, but by time we moved on to other targets, the scope had moved about 2 degrees from where I first saw it. Overall, about half a dozen of us saw the asteroid moving. Having an equatorial mount with motor control of both axes was definately a big help in following the asteroid. I just had to offset the scope to the NW, then figure out which faint "star" in the field was moving again, for the next person to take a look. Later on, we determined that the limiting magnitudes of the 12.5" was around 15.3, and for the 80mm around 13.5 near zenith. We're not quite sure why it wasn't found in the refractor. At such low elevations, there is more extinction and the sky is brighter, which would make it harder to find. Also, I believe the refractor was using lower magnification than I was with the 12.5".

Did anyone else attempt to see this NEA? Any success?

Cheers
Mike Connelley

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Michael Connelley said:

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Did anyone else attempt to see this NEA? Any success?

Cheers
Mike Connelley

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Hi Mike,

Well ... I tried here in Northern, CA. We had good seeing for this location actually, maybe mag 5.5 skies. I first brought out the big bino's, and with a tremendous amount of imagination, I thought I saw something wink in and out along a straight line in the Cassiopeia area (8:00UT) according to the maps I downloaded from Sky and Tel. Then I pulled out my 10"SN for a closer look, but now could no longer see anything moving as I traced up the sky following the map time line. So I would call it a maybe minus.

I did have some fun setting up the equipment though, and had a very nice wide field tour of Cassiopeia.

Attached Image:

http://skyandtelescope.com/printable/observing/objects/asteroids/article_1755.asp

Geoff Gaherty reported seeing it from Canada through an 11" Starmaster.

Dave Mitsky

An observing buddy and I tried to see the asteroid pass and were thwarted by hazy skies and our own malfeasance. We had the excellent charts from the Sky and Telescope website. We were using my friend's V11 Starmaster scope and a 14 inch Newtonian on a GEM with attached CCD camera. We started our attempt when the asteroid was quite low in the northeastern sky and immediately discovered that low lying muck and haze was going to make that impossible. Even Gamma Andromeda was dim and the most unspectacular I have ever seen it. We both had to work the next day so we slept for two hours and then resumed the effort when the asteroid was about to pass the brighter stars in Casseopia. We entered a coordinate wrong in the computer driving the GEM for the 14 inch and ended up imaging the wrong segment of sky. My friend's wife proclaimed she had found it in the V11. I ran to the eyepiece to find a 10th magnitude satellite moving slowly north to south (opposite direction of the path of the asteroid) through the field of view. Although it was immediately obvious that one had to move the scope in the wrong direction to track this object it may have been the highlight of our night. When the asteroid left Casseopia and headed toward Cepheus we found a dearth of nearby bright stars to use to attempt to locate it.
So, at the risk of embarassment about our Missouri skies and Katzenjammer antics, that is the tale of how we failed to find the rascal. No one should expect us to locate any near earth asteroids that threaten life as we know it.