Asteroid (116) Sirona Occultation Nov. 10/11, Delmarva to El Paso
The occultation of SAO 110124 was observed from at least 6 locations from the Shenandoah Valley in Virginia to southeastern Arizona
The path shifted about half a path-width north, and reported step and "flickering" events indicate the star is probably a close binary
Updated: 2005 Nov. 12, 0h UT
If you have a 5-inch or larger telescope, we need your help to observe the occultation of 10.3-mag. SAO 110124 = TYC 0622-00932-1 by the 72-km asteroid (116) Sirona, visible Thursday night, Nov. 10/11 (convenient for those who have Nov. 11, Veterans Day, off) The reports so far for this occultation are as follows. The first number is the distance from Steve Preston's predicted central line, in km, positive to north of center and negative for south of it. Most observers reported "flickering" or partial events, indicating that the star may be a close double. +144 *** predicted northern limit with 3 sigma n. shift *** +136 w Derald Nye, Corona de Tucson, AZ - clouded out * +109 *** predicted northern limit with 2 sigma n. shift *** +74 *** predicted northern limit with 1 sigma n. shift *** +72 + Berton Steves, Las Cruces, NM +68 + Frank Miller, Las Cruces, NM - observed visually +67 + Robert James, Las Cruces, NM - 3.40s occ'n, video +59 + Doug Snyder, Palominas, AZ - 4.1s complete occ'n, video +45 w Joe Sedlak mobile in VA - clouded out +39 *** predicted northern limit *** +35 w David Dunham #1 clouded out, Cedon, VA +15 + Tim Farris, Madison, TN - 5s complete occ'n, video +14 + John Goss, Fincastle, VA - 4.7s complete occultation -13 - Michael Good, Roanoke, VA CCD drift scan, no occultation -35 ? David Dunham #2, Varina, VA, probably clouded out -39 *** predicted southern limit *** * Note: Derald Nye did observe a 4-foot rattle snake in his garage when he went out to check the weather for the Sirona occultation. He called the fire department to take care of it. Extensive pre-event prediction and planning information is here. One message about the occultation, and my response, is below: From: David Dunham [dunham@starpower.net] Sent: Friday, November 11, 2005 11:22 AM To: John & Genevieve Goss Cc: IOTAoccultations@egroups.com; Dunham, David Subject: Re: (116) Sirona from Fincastle, VA John, Many thanks for your positive observation at 14 km n. of the predicted center. Robert James in Las Cruces, 67 km n. of center, also had an occultation, and there are a couple of other positives around that line. Michael Good in Roanoke, VA, at 13 km s. of the predicted line, had no occultation. So the path must have shifted north by about half a path-width. I wonder if the "flickering" that you saw, and some anomalies reported by others, indicate that the star may be a close double? I ran two stations, each just inside the predicted limits, at Cedon and near Varuna, VA. It was the widest separation between my remote and attended station that I've run, 51 road miles. At the n. site at Cedon I was clouded out; too bad since an occultation must have occurred there. I haven't reviewed the Varuna tape yet, but it must have been a miss, even if it wasn't clouded out (but it probably was). I set up a 3rd station near Carmel Church but didn't run it since I was not able to accurately pre- point it before it clouded up there. The un-forecast clouds were a bummer; glad others obtained timings. David At 10:11 AM 11/11/2005, you wrote: >Hello David, > >Finally, I saw one! > >I located the asteroid and star at 10:00 pm EST. By 11:50, I had >difficulty separating them and by 11:55, I couldn't. > >My response delay was approximately 0.3 seconds. I was surprised that the >star did not dim instantly but instead flickered for about 0.7 seconds >before the pair dropped to the asteroid's magnitude. When the star >brightened, it again flickered for about 0.7 seconds before achieving its >full brightness. > >Sky brightness: 74% illuminated moon about 40 degrees away. There was no >trouble observing the asteroid and star. >Seeing: a little better than average (4 out of 5). > >Timing Results: (116) Sirona, November 11 at 12:01 am EST >BEFORE taking my estimated 0.3 second response delay into account: > >Start flickering: 12:01:21.9 >Fully dimmed: 12:01:22.6 >Start flickering: 12:01:27.3 >Fully brightened: 12:01:28.0 > >AFTER taking my estimated 0.3 second response delay into account: > >Start flickering: 12:01:21.6 >Fully dimmed: 12:01:22.3 >Start flickering: 12:01:27.0 >Fully brightened: 12:01:27.7 > >Technique: Used 9mm Nagler (280x) with a 10 inch f10 Meade L6 SCT. >Time signal from WWV 5000kHz >Read into an audio cassette recorder. > > >John Jardine Goss >932 Lee Lane >Fincastle, VA 24090