Occultation of 9.4-mag. TYC 2416-00772-1 by (187) Lamberta on 2007 December 20 - Updated 2007 Dec. 21, 21h UT
The occultation was observed by at least a dozen observers across the USA
Steve Preston's path prediction was very accurate
Very preliminary information about this well-observed event is given in the summary list below. The reported central durations were almost 2 seconds longer than predicted, while possibly the path was a few km narrower than predicted. More about these and other previously-observed occultations is/will be posted on Brad Timerson's N. American asteroidal occ'n results page, IOTA's official Web site for North American asteroidal occultation results. __________________ Last night's (187) Lamberta occultation was very well-observed across the country. A summary below is compiled from several e-mail messages. Dennis Rowley notes "a bunch of positives" from the Norfolk, VA area, so we'll probably have a few more to add, as well as more detailed info. later about the known reports. The path prediction was quite accurate, with miss observations made near both predicted limits. The same codes as used for the predictions indicate how the observations were made: * for visual at home, V for video at home, m for mobile visual, M for mobile video. "positive" means that an occultation was observed, with times to be reported later; the other times are mostly preliminary estimates and will be refined. Occultation of TYC 2416-00772-1 by 187 Lamberta on 2007 Dec 20 Uncertainty in time = +/- 3 secs [Prediction of 2007 Dec 6.3] Distance (+ north of center, - south of center) from center, in km Observer and/or location 79 * miss Lexington KY Otto Piechowski 65 *** Path Northern limit *** 65 M miss Mechanicsville VA David Dunham 44 * positive Richmond VA John Raymond 36 * 8.4s occ'n Fincastle VA John Goss RVAS 29 M 8s occ'n Hopewell VA I295/VA36 David Dunham remote 18 * positive Grundland AstroPk VA Mike Klosterman, L. Taylor, D. Kratz 15 V 9.2s occ'n Santa Fe NM Gene Mroz 0 M 10s occ'n Paul Maley mobile in Okla. 0 **** Centre Line **** -10 * 10.0s occ'n Chesapeake VA Dennis Rowley -26 M 9-10s occ'n Ochelata, OK John Grismore -40 M 8.8s occ'n Big Cabin OK Bob Sandy mobile -46 m 8.1s occ'n s. Albuquerque NM Kevin McKeown -50 M 7.90s occ'n South Mills NC Kathy & Harry Abramson -65 *** Path Southern limit *** -69 M miss Las Lunas NM Steve Welch -120 V miss Nashville TN John Graves For this event, we did obtain coverage with some stations outside the path within the 1-sigma limits, but this is a relatively rare case that the prediction was so accurate that these "outer" stations all had a miss. Normally, there's enough error in the predictions that someone within the 1-sigma zone outside the path will have an occultation. Since we don't have any really short (less than half the central duration) chords near the edges, the closest misses should provide useful constraints on the solution ellipse. Kevin McKeown had the most adventuresome trip. He had to run from home to get away from clouds, and ended up in a bad neighborhood of Albuquerque where locals harrassed him during his successful observation. He has now reported his long. and lat., and I used that to find out, via the google maps item for this event on Derek Breit's global Web site, that he was 46 km south of the predicted center line. ___________________ David: I had a great view of the Lamberta event tonight (Dec. 19th, 2007). As usual it seems, I had to fight clouds, and "go mobile" at the last second. To find clear skies, I had to travel into the far South Valley of Albuquerque- so far south that I worried about missing the event. As soon as I got southwest enough of a big cloud bank over eastern Albuquerque, I pulled onto a dark side street. Or so I thought. I had to put up with drag racers, people shouting profanity at me, and I even had to dodge a McDonald's soda cupful of ice thrown at me! (The telescope survived all this.) I got things set up in about 12 minutes. I found the star immediately- I was prepared on how to find it. The scope was already cold, and ready to go. The star was bright in my 8" refl. When its light was cut off, there was no trace of the asteroid! As it turns out, I timed at least 8 seconds of occultation- the star was out for forever, it seemed. There were no tormentors around when the event occurred. But I saw it clear, and got great timings. I'll get these to you tomorrow- I'm very tired, and COLD right now. (The valley temperatures are much much colder than in the Heights of Albuquerque where I live.) Kevin McKeown ___________________________ Pre-event predictions and plans are here. David Dunham, 2007 Dec. 21, 4 pm EST Phones home 301-474-4722; office 240-228-5609; cell 301-526-5590 office e-mail david.dunham@jhuapl.edu with Blackberry for mobile use home e-mail: dunham@starpower.net .