Asteroid (116) Sirona Occultation Nov. 10/11, Delmarva to El Paso
Dozens of telescopes are in this path, also over Richmond, Nashville, Memphis, Little Rock, Lubbock, and n.w. Mexico
At low altitude, the path is over southern Iberia, just n. of Lisbon, Portugal
Clear Sky Clock forecasts mostly clear skies along most of the path, from Chesapeake Bay to s.e. NM
The 10.3-mag. star should be easy to find a degree south of 4.5-mag. omicron Piscium
Updated: 2005 Nov. 10, 19h 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) from a path passing over the Delmarva Peninsula (Assateague Is., MD is near the center at 5:00 UT = 12:00 am, midnight, EST Nov. 11) and across the USA to El Paso, TX and southwesternmost New Mexico at 5:04 UT Nov. 11 UT = 10:04 pm MST, and then across n.w. Mexico with Cananea Observatory near the n. limit and maybe San Pedro Martir near the path at 5:05 UT, with only a small chance for an occultation from the southernmost tip of Hawaii island at 5:11 UT. At 4:56 UT Nov. 11, the path also passes over southern Iberia, just north of Lisbon, Portugal where the altitude will be 7 - 8 deg. in the west. For more information about this event, see Steve Preston's Web site that has detailed finder charts of different scales to easily locate the star. If you can help us observe this occultation, either from your home or observatory, or as a mobile observer, please inform me and Derek Breit (e-mail breit_ideas@hotmail.com ). For coordinating coverage of this occultation, a list of stations sorted by distance in km from the predicted central line, can be found on Derek Breit's Web site. You can search for your, or your town's or observatory's, name to see just when the occultation is predicted for your area (that time should be accurate to within 15 seconds or so), the probability for having an occultation there, and the predicted Sun and star altitudes at the time. If your station is not in the list, send me and/or Derek Breit your coordinates, or your street address, and we can add it. Derek will update his Web site with information indicating which distances from the central line (or "chords") will have observers trying to time the occultation. For information about timing occultations, click here. The 3rd Astro Meteo forecast (on which Clear Sky Clock is based) that is virtually identical to the 2nd forecast; it predicts for the Sirona occultation clear skies from the western shore of the Chesapeake Bay in Virginia all the way to southeastern Arizona, and also clear from Wichita Falls to El Paso, Texas, and again from western Sonora to the Pacific Coast in Mexico. Thin clouds, with partly cloudy skies, are expected from Ardmore, OK to Wichita Falls, TX, and thicker clouds are expected over the Delmarva Peninsula & most of southern Maryland, and also over southeastern Arizona and northeastern Sonora. This may change a little before the event; especially those near the boundaries between clear and partly cloudy skies should check later forecasts. The coverage so far for this occultation is 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. +189 w Jim Stamm, Oro Valley, AZ +144 *** predicted northern limit with 3 sigma n. shift *** +136 w Derald Nye, Corona de Tucson, AZ +109 *** predicted northern limit with 2 sigma n. shift *** +74 *** predicted northern limit with 1 sigma n. shift *** +68 Frank Miller, Las Cruces, NM +67 Robert James, Las Cruces, NM +59 w Doug Snyder, Palominas, AZ +45 Joe Sedlak mobile in VA +39 *** predicted northern limit *** +35 David Dunham #1 in VA +25 Wayne Warren, Jr. mobile in VA +14 John Goss, Fincastle, VA +12 Bob Oldham, Dovecote Obs., Oliver, VA +7 John Graves, Dragonflight Obs., Nashville, TN 0 Rich Richins mobile to Univ. Texas at El Paso -3 Lone Star Obs., Barry Smith, 24" telescope available -11 Mark Manner, Spot Observatory, TN -13 Michael Good, Roanoke, VA CCD drift scan -24 Randy Tatum, Richmond, VA -35 David Dunham #2 in VA -39 *** predicted southern limit *** -50 David Dunham #3 in VA -74 *** predicted southern limit with 1 sigma n. shift *** -92 Danny Caton, Dark Sky Obs., NC -109 *** predicted southern limit with 2 sigma n. shift *** Derek Breit has included most of these in his station list on his Web site with link given above. Later, I will put a "w" for observers who will probably be clouded out, and "?" for those who may be clouded out (weather forecast for them "iffy"). I hope to try to observe the occultation from Virginia, from as many as four locations, probably along US 17, or possibly US 301, with a smaller chance of US 13 on the Delmarva peninsula. If any Virginia or DC- region observers want to help me with this, let me know. You can see the path superimposed on very detailed maps and satellite imagery on Charlie Ridgway's Web site. For general information about his site, click here, while for the map specifically for the Sirona occultation, click here. On this site, you can enter a distance from the central line in km in a special "offset" box (just write over the default value of 1000 given there) and it will plot gray lines at that distance north and south of the central line. Type your distance number (in km) in the box just to the left of the "Plot Offsets" box at the bottom of the map. You need to type a number with no sign, then two gray lines are plotted; zoom in on the gray line northeast of the yellow central line if your distance is + and on the gray line southwest of the central line if your distance is -. You can move the map by grabbing it (left-clicking and holding down) and you can zoom in or out by left-clicking on the scale in the upper left part of the map (+ on that scale means "zoom in" for more detail over a smaller area). You can toggle between "map" (showing town and road names), "satellite" for satellite imagery, and "hybrid" for both together. The target star is about 5 deg. northwest of 3rd-mag. alpha Piscium at J2000 RA 1h 46m 51.5s, Dec +8 deg. 16' 08"; the target star is one deg. south and a little east of 4.5-mag. omicron Piscium (named Torcular and = ZC 257), 0.4 deg. southeast of 6.5-mag. ZC 258 = SAO 110111. Within 3' of the target star are 2 11th-mag. stars north of it and one south of it. This should be an easy star hop, but for pre-pointing telescopes, I will figure out stars at the same declination as the target star west of it, and give that information in a later message. The spectral class of the target star is F2. If an occultation occurrs, it would last up to 6 seconds with a 2-magnitude drop. The path over Delmarva and the El Paso area and farther east were described above. At 5:01 UT (12:01 am EST), the pasth sweeps across east-central and southwestern Virginia with Richmond near the center, and over s.e. Kentucky and n.w. Tennessee, with Knoxville near the s. limit. At 5:02 UT, it passes over central & western Tennessee with Nashville near the center, and also central Arkansas just north of Little Rock. At 5:03 UT (11:03 pm CST Nov. 10), the path crosses southeastern Oklahoma and north-central Texas with Ardmore, Okla. and Wichita Falls, Tex. near the center. At 5:04 UT, the path passes over west-central Texas and southern New Mexico with Lubbock & El Paso in the path, and also Carlsbad, New Mexico. Barry Smith offers use of the Lone Star observatory, even can provide overnight accommodation there, to anyone who wants to observe there - his message is below. I hope that he, or someone else who normally works there, can attempt the observation if nobody can travel there to take him up on the offer. Below is his message: _______________________________ ----- Original Message ----- From: w barry smith To: breit_ideas@hotmail.com Sent: Wednesday, November 09, 2005 1:28 PM Subject: Observing Sirona I've never done an occultation but our facility is almost directly under this one (-3 km). Caney, OK. From one of the links in the message. -3 74% Lone Star W Barry Smith, 24" - 96 8.3 34 11.0 5 3.3 (time 5:03.3 UT predicted there) 0.002 64 -68 We have a large 24-inch Cassegrain at f/16, thus mega focal length (9686 mm) and really large bright images. Fully computerized, can find the star is about 10 seconds. I'm willing to host any experienced occulters (?) who would like to use our scope and faculties. Don't have a ham radio, but do have a VCR and super quality CCD. A former member frequently attached his Canon video recorder with removable lens to the scope. The observer is free to crash at our facility for the evening (heat/air conditioned, internet access, full bath, full kitchen), thus no lodging expenses. Go to www.lonestarobservatory.org to see particulars of the facility then either e-mail or call me. I could be there not later than 7PM, which would give them time to test and sort out the best technique they want to us. No charge for anything of course. W. Barry Smith Chairman Lone Star Observatory www.lonestarobservatory.org 817-491-2605 Home (first choice) 817-201-6658 _______________________________ It would be great to use with a Supercircuits PC164C or even PC23C video camera. David Dunham e-mail home dunham@starpower.net; office david.dunham@jhuapl.edu