(1315) Bronislawa south shift to DC, Baltimore
Two video chords and a very approximate visual one for the April 20 (UT) occultation will constrain the asteroid's size and shape
Many others in and north of the predicted path had no occultation
Updated: 2006 April 21
[Message to Dale Lehman, Essex, MD, with updated list of observations] Dale, Thanks for your observation; you almost certainly did see the occultation, since your time corresponds closely with a positive video observation by Don Garner. Below is a list of the observations that have been reported so far: Dist. from pred. center, km +89 Don D'Egidio, Plymouth, PA, video, no occultation +63 Cliff Bader, West Chester, PA, video, no occultation +26 David Dunham remote, Oxford, PA, video, no occultation +26 Eric Briggs, Ontario, video, no occultation +21 Bill Watson, NY, visual, no occultation +10 Joe Sedlak, e. of Smyrna, DE, visual, no occultation -17 Wayne Warren, Riverside, MD, visual, no occultation -42 You and Jose Guzman, Essex, MD, visual, 2-3 sec. occultation -61 Curt Roelle, Marston, MD, video, 5 sec. occultation -74 Don Gardner, Columbia, MD, video, 7 sec. occultation -460 Jay Faircloth, Kinston, NC, visual, no occultation Don's long event, a little longer than the predicted central duration and close to the predicted time, shows that he was probably near the center. It's too bad your and Jose's video attempt failed, and also that Tom Whiting was clouded out near -30 south of Erie, PA. Since the predicted path width was 79 km, Wayne's and your short event, near the northern limit rather than near the southern limit, indicates that the path shifted at least 1.2 path-widths, or over 1.5 sigma, southwest of Preston's prediction. I should have set up a remote station at home that my wife could have run. If there are any other observations in the Washington - Baltimore - central Maryland region, or elsewhere down to the 2-sigma southern limit, we'd be interested in hearing about them. I started my recording at Oxford, PA about 40 min. before the occultation, so I drove farther east, to the intersection of US 1 and PA Hwy 41, and tried to observe there, too, at about +38. I may have got on the target star about the time of the occultation, but the star was VERY faint with my 5-in. SCT and PC164C (the Oxford station used an 8-in. SCT that showed the star reasonably well). I had hoped to also use an image intensifier, but didn't have time to connect it until after the event. With the image intensifier, the target star was relatively bright, and the approx. 12.5-mag. stars near it were also recorded well. Since a miss must have occurred there, it probably matters little that I wasn't able to make a good observation there. David At 01:13 AM 4/20/2006, lehket@netscape.net wrote: David, Jose and I attempted to observe the Bronislawa occultation with his 10" SCT, but unfortunately we are not able to report any definitive results. Our initial problem with the video was corrected by plugging into the power in my house, but the screen didn't show any stars after that. [The battery that powered the video camera was probably dead]. We decided to observe visually and were set up with the target star acquired a few minutes before the predicted time. I did the observing. Although the target star was just visible in his scope, it was faint enough that I could not keep it constantly in view. I lost it several times during the observing period and thus am not able to say with certainty whether or not an occultation occured. I feel there may be about a 50% chance that an occultation did take place sometime between 11:40:50 and 11:40:58 EDT, lasting perhaps 2-3 seconds. The loss of the star at about that time was noticeably longer than earlier instances, which typically lasted only a second or less. But again, I can't be sure that this was not simply a case of the star briefly eluding me. On the plus side, we had an enjoyable evening and both gained some additional experience. It was interesting for me to see all the gadgetry hooked up and almost working. ;-) --Dale _____________________________________ - And messages to and from Curt Roelle, Marston, Maryland From: David Dunham [dunham@starpower.net] Sent: Thursday, April 20, 2006 12:15 PM To: Roelle, Curtis W Cc: IOTAoccultations@egroups.com; GFrishkorn@aol.com Subject: Bronislawa occultation recorded at Marston Obs., MD Curt, Many thanks for this observation at -61 km. Now we have two well-timed chords (yours and Don Gardner's at Columbia, MD) and the approximate one at Essex, MD, so we'll get some idea of the size/shape of Bronislawa. But too bad that, at least so far, there weren't more observations, especially a little farther south, in the Washington, DC area & suburbs. Also, many thanks to Cliff Bader for successfully video recording the target star from his home at West Chester, PA, at +63 km in spite of his recent hospitalization. And thanks to Eric Briggs who also video recorded a miss from a mobile site in Ontario at +26 km, but unfortunately very close to my chord at Oxford, PA due to lack of coordination. David At 10:12 AM 4/20/2006, you wrote: >Dave, > >I recorded a solidly positive event that was a good five seconds in >duration. Reviewing the tape it looks like it occurred roughly between >03:40:53-58 UTC. > >Curt Pre-event predictions, charts, and plans are here. __________________________________________________ David Dunham, IOTA home dunham@starpower.net 301-474-4722 cell 301-526-5590 office david.dunham@jhuapl.edu 240-228-5609