Five Asteroidal Occultation Early Results, 2004 June 30 - July 6
2004 IOTA Meeting was held July 2-3 in Apple Valley, Calif.
Updated: 2004 July 9
Below is an incomplete list of observers who tried to observe at least one of the five asteroidal occultations. Preceding the name I've put columns for the 5 California asteroidal occultations, "30" for the June 30th Helga event, "1" for July 1 Nanon, "3" for July 3 Angelina, "5" for July 5 Fidelio, and "6" for July 6 Carina. A "+" means that the occultation was observed, a "-" that the star was monitored but that no occultation occurred, "?" that a recording of the target star was made, but it was faint so that closer analysis of the tape will be needed to see if an event occurred or not (or I don't know what the status of the observation is), and "x" that the observation was attempted, but failed due to clouds or other reasons. 30 1 3 5 6 x - + Frank Anet - Martin Bonadio (Ariz., not at meeting) x - ? - Derek Breit + Bob Cadmus (Iowa, not at meeting) + John Centala (Iowa, not at meeting) - Steve Dodder (Arizona, not at meeting) + + - David Dunham ? Steve Edberg (Calif., not at meeting) + Joe Eitter (Iowa, not at meeting) Daniel Falla + Sam Herchak (Arizona, not at meeting) + Erik Hubl (Nebraska, not at meeting) - - - Bob Jones Lampert Levy - + - Art Lucas Gene Lucas + - ? Greg Lyzenga + - + Paul Maley - John Matthews (Ariz., not at meeting) Ralph Megna - - Dave Meyer - Ed Morana (Calif., not at meeting) ? Charles Morris (Calif., not at meeting) + + x Walter Morgan x - + x Richard Nolthenius + + - Richard Nugent x + - Derald Nye + David Oesper (with Eitter, not at meeting) - Randy Peterson + - Harold Povenmire (with Nugent) ? Steve Preston (with Breit) + Hank Sielski (with Dunham) Norm Sperling - Jim Stamm (Arizona, not at meeting) + Don Stockbauer + - + x Jim Stoffaire Bill Walsh - - x Wayne & Martha Warren Gary Witt - Karen Young (Calif., not at meeting) __________________________________ JUNE 30 - Wednesday 0:07 am (522) Helga occulted 10.8-mag. TYC 6310-01494-1, s. San Joaquin Valley, n. Mojave Desert, Las Vegas (and earlier east to Nebraska and Iowa). Click here for a very perliminary sky plane view (NOT including all observers yet) and click here for a list of the observations entered so far (in Occult .OBS file form, a plain ASCII text file); I have some observations that have not been entered yet, so don't complain if your data are not included; if I have them, they will be included in another update next week. JULY 1 - Thursday 2:48.4 am (559) Nanon occults 8.6-mag. SAO 161827, Orange County, Riverside, San Bernardino Mountains, s.e. Mojave Desert (and earlier east to n.Arizona and n. Minn.). Click here for a very perliminary sky plane view (NOT including all observers yet) and click here for a list of the observations entered so far (in Occult .OBS file form, a plain ASCII text file); I have some observations that have not been entered yet, so don't complain if your data are not included; if I have them, they will be included in another update next week. JULY 3 - Saturday 4:19.0 am (64) Angelina occulted 11.9-mag. TYC 1215-01306-1, San Fernando, Bakersfield, n. Mojave Desert, Las Vegas This was successfully observed from several mobile sites along US 395 from Adelanto (west of Apple Valley) and Kramer Junction, as well as from a couple of observatories farther west in California; results will be posted here soon. JULY 5 - Monday 1:53 am (524) Fidelio occults 10.9-mag. TYC 6913-00447-1, Santa Rosa, Sacramento, Reno, Salt Lake City (and earlier east to s. Wyoming, S. Dakota, & n. Minn.) There are no known successful observations of this event. JULY 6 - Tuesday 4:28 am (491) Carina occults 9.9-mag. TYC 0483-01460-1, San Diego, El Centro, Yuma, Phoenix, central New Mexico (but this shifted north to San Bernardino, CA & Payson, AZ) This was observed by Sam Herchak near Payson, AZ, a 6-sec. occultation. All other known observers had no occultation, including Bob Jones a little s. of the predicted northern limit, showing that an approximately 2.6-sigma northward path shift occurred, the largest prediction error relative to the claimed accuracy in recent memory - we are investigating for possible reasons. This set another record when I deployed 4 telescopes and cameras at about 5-mile intervals for 16 miles near Calif. route 111 east of El Centro, the largest deployment for an asteroidal occultation by one observer. Three of the systems were pointed in the right direction half an hour before the event when I ran out of time and had to go to the other stations. Unfortunately, in clamping the third pointed telescope, I accidentally loosened rather than tightened the Dec. clamp and the telescope swung, losing the pointing. When I got to the northernmost station, the telescope was gone, taken by a nearby migrant farm worker, and recovered a few minutes after the occultation (more about that later). So one telescope, a Meade 4" ETX with f/3.3 focal reducer and PC164C camera, successfully recorded the target star at the right time, but had a miss, like all the other observers south of Herchak's chord. _________________________________________________ Prediction information for these events, with several maps, is given below (from June 29) Steve Preston has calculated early updates for the following asteroidal occultations in North America. But he has recently calculated updates for all of these events and, except for a new bright near-Earth event given below, has posted them on his Web site which supersedes the information here. However, he does not have the combined maps that are at the bottom of this page, and his new paths are very similar to the earlier-computed ones shown here. HOWEVER, for the important occultation by (559) Nanon on July 1, the path has shifted almost a path-width south of that shown here, with the latest updates. The star's magnitude, called "* mag." for short, is given after the asteroid's name. I've removed the earlier links to this old information (you should get it instead from Steve Preston's site above; he also includes good finder charts for all of these events), only listing the events below, but including some new detailed maps of some of the updated paths by Walter Morgan below the list. 2004 June 30, (522) Helga, * mag. 10.8, Que. to Calif. 2004 July 1, (559) Nanon, * mag. 8.6, Minn. to Orange County, Calif. 2004 July 3, (64) Angelina, * mag. 11.9, s. Calif., Las Vegas 2004 July 5, (524) Fidelio, * mag. 10.9, w. Ont. to n. Calif. 2004 July 6, (491) Carina, * mag. 9.9, Phoenix to San Diego Walter Morgan's California maps with Preston's latest path updates as of June 27: June 30th, Helga across California July 1, Nanon Riverside & s. Mojave Desert July 1, Nanon Orange, n.San Diego, & w.Riverside Counties July 1, Nanon s.Nev., nw Ariz., se Utah, w&n Colorado July 1, Nanon ne Nebr., e. S. Dakota, Minnesota July 3, Angelina Ventura to Mojave Desert July 5, Fidelio n.Calif., n.Nev., n.Utah, sw Wyoming July 5, Fidelio e.Wyo., S.Dakota, se N.Dak., n. Minn. July 6, Carina San Diego County, Salton Sea area, Calif. July 6, Carina s.e. Calif., Ariz. (Yuma to Phoenix) July 6, Carina s. New Mexico July 6, Carina s. New Mexico & n. Texas (bright twilight) In addition, Steve has produced 3 maps showing all 5 of these paths over the southwestern USA, including major cities and highways. But BEWARE, THESE PATHS ARE OLD; ESPECIALLY THE NANON PATH HAS SHIFTED WELL SOUTH OF THE POSITION SHOWN ON THESE MAPS; ESPECIALLY FOR IT, USE INSTEAD WALTER MORGAN'S MORE DETAILED AND UP-TO-DATE MAPS ABOVE, or visit Preston's Web site. The first of these maps is the clearest, since the other two also include the 1-sigma error limits, useful information but it makes the plots a little cluttered. A 4th plot zooms in on southern California showing the four paths there and smaller highways and cities, including Apple Valley, where the IOTA meeting was held, in the Mojave Desert north of San Bernardino. s.w. USA, paths shown in light green s.w. USA, like above, adding the 1-sigma limits as red lines s.w. USA, like above, but path n. & s. limits are blue lines southern California, paths shown in light green ___________________________________________________________ A summary of the five events crossing California, next 10 days: 2004 Asteroid S t a r Date U.T. Diam., R.A.(2000)Dec. June h m m # Name km mag. h m o / Approx. location 30 7:02-:07 522 Helga 101 10.8 19 31.3 -20 45 ON,WI,IA,NE,CO,AZ,cCA July 1 9:46-:48 559 Nanon 79 8.6 18 47.6 -19 52 MN,SD,nwCO,UT,sNV,LAX 3 11:19-:19 64 Angelina 97 11.9 02 21.5 +15 16 s.Calif.,s.NV-LasVeg. 5 8:49-:53 524 Fidelio 71 10.9 20 09.7 -27 29 nMN,SD,WY,nUT,nNV,nCA 6 11:27-:41 491 Carina 97 9.9 19 42.4 +02 45 NM,PHX,CA-SanDiego,PI July 1: The star is SAO 161827, spectral type F8; Nanon is type C. I will soon calculate station lists for these events so we can coordinate coverage of them; of course, some updates will be made at brief meetings the evenings before each event with possibilities given in the schedule here. The station list for tonight's (522) Helga occultation is here. David Dunham