Asteroids - by the light of the silvery moon

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Pete
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Asteroids - by the light of the silvery moon

Unread post by Pete » Sat Dec 18, 2010 8:01 pm

Friday, 17 Dec 2010 It’s been a clear day and tonight’s sky is pretty decent for observing. The dome’s opened and running by 17:00 hrs. Air temp is a balmy 30°F. The almost full moon is high in the sky, so the plan is to work stuff at least 45° from the moon if possible.

207945 is an 830 meter sized potentially hazardous Apollo presently 11 million miles distant, 17.5 magnitude, moving 4’/hr. Uncertainty level is 2. Imaged 1 min, 2X2, -30C, 1 Hz from 18:06 – 18:18. I’d originally tried for -35C but the camera couldn’t hack it. Frames 1, 4 & 7 show dRA = -0.2’ and dDEC = +0.6’

249886 is a 2.3 km sized Amor now .6AU distant, 18.6 mag, moving 2.8’/hr. 90 second exposures were taken from 18:29 – 18:53 hrs. Using track & stack, frames 1-2, 6-7 and 11-12 show dRA = -0.1’ and dDEC = +0.2’.

198856 is a 2.6 km sized Amor presently .36 AU distant, 17.1 magnitude, moving 3.3’/hr. Imaged 1 min, 2X2, -30C, 2 Hz from 19:06 – 19:24 hrs. I’m only 33° from the moon and a part of each image is badly wiped out from reflections off of the corrector plate. Fortunately the asteroid’s in a protected corner and frames 1, 6 and 12 show dRA = +0.1’ while dDEC = -0.1’

2010 XE11 is a 166 meter sized Amor discovered only 8 days ago. It’s presently 7.5 million miles distant, 19.2 magnitude, moving 3.6’/hr. Uncertainty level is 6, as one would expect with a recent discovery. Imaged 90 sec, 2X2, -30C, 10 Hz from 19:25 – 20:01 hrs. Using track & stack, frames 1-3, 4-6 and 7-11 show dRA = +2.5’ and dDEC = 0’ XE11 is very low in the north, and seeing has deteriorated significantly as the last frames are taken, requiring the capture and stacking of additional frames to accurately measure the third position.

2010 XX58 is a 1.3 km sized asteroid that is as yet unclassified as it was only discovered 2 days ago. Only 28 observations have been made on it. Uncertainty level is 8 out of 9. Presently it’s .56 AU distant, 19.2 magnitude, moving 3’/hr. And its low in the NE. Imaged 90 sec, 2X2, -30C, 2 Hz from 20:16 – 20:50 hrs. Using track & stack, frames 1-5, 6-10 and 11-18 show dRA = +0.5’ and dDEC = -0.2’

It’s been a long and hard day. Air temp’s down to 27° and since I never bothered to suit up I’m feeling it. The dome’s shut down by 21:00 hrs and the data has been emailed to the Harvard/Smithsonian within 5 minutes – from inside the warm house.

hgp 18 Dec 2010
Pete P.
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