Need help to cover Niobe path tonight; path may be more west?
New: 2005 February 9
We need your help to cover tonight's occultation of 8.0-mag. SAO 38784 by the 83-km asteroid (71) Niobe. As noted in messages sent the last couple of nights, this is the best asteroidal occultation in North America this month. Let us know if you might be able to attempt this occultation so that mobile observers can move to locations that won't duplicate YOUR chord. Maps of the updated path crossing North America from Ontario to Louisiana, and finder charts of different scales, are on Steve Preston's Web site. The Path (the star's probable close duplicity adds uncertainty): For the path, it's best to look at Preston's Web site above to see the eastern and western limits as solid lines and the 1-sigma eastern and western limits as dashed lines; the detailed maps show the eastern and western limits as black or dark blue lines, and the 1-sigma limits as red lines. The occultation will occur late during 5h UT, that is, after 11 pm or shortly before midnight, CST, tonight, Feb. 9 (but Feb. 10 UT). Essentially, the path passes over westernmost Ontario, Minnesota, Iowa, Missouri, Arkansas, and Louisiana. That's the path computed using the UCAC2 and TYC2 data for the star (both in good agreement), and is probably the best; however, a prediction using only Hipparcos data moves the path about a whole path-width farther west, which means that the occultation might occur in cities such as Winnipeg; Omaha and Lincoln, Nebr.; Kansas City and Topeka, KS; and Shreveport, La. Observers there should watch, and possibly farther east, too. The star is suspected as double (but not clearly resolved) by Hipparcos, and the duplicity could be the cause of the prediction differences. Because of these differences, and the relatively small angular size of 0.04" of Niobe, I've decided not to travel to the path from Maryland. Weather: Clear Sky Clock shows clear sky over Arkansas, and mostly clear over Louisiana, but some clouds there. It shows a fair amount of clouds over most of Missouri, but rather clear in the westernmost and southernmost areas, and mostly clear in adjacent parts of Kansas. Variable amounts of clouds are predicted for the path north of Missouri. The IR weather loop at 6 pm CST shows a lot of clouds heading into Louisiana, and even a few clouds scattered over Arkansas; it looks like just more clouds will move from the west into Louisiana. Also, clouds are moving from the northwest across northern Missouri, with more behind, so it's not obvious now whether or not it will be clear in the Kansas City region. Cloud cover remains rather thick in the path north of Missouri, but it's so cold there that it's hard to tell the clouds in the IR images. Below is a first version of the station list for this event indicating possible coverage of the event. If I don't have your station, please send your location information so that I can include you in another update either late tonight, or tomorrow (Wed.) morning and/or evening. Let me know if you plan to observe and aren't so indicated in the station table below, so I can include you in the next update to help mobile observers from duplicating your chord. You can suggest a station from the list, or you can send me your planned location, if it's not in the list. Stations for the Niobe occultation of 2005 February 9/10 Below is a list of observer stations sorted by distance from Steve Preston's central line, updated on 2005 Jan. 8. Distances are given in km measured perpendicularly from the central line. The time gives the updated time (U.T.) of closest approach (the U.T. date is 2005 Jan. 28), when the occultation should occur, within an accuracy of about +/-0.3 minute, at the location. You only need to monitor the star for an occultation within a 2-minute period centered on the time of closest approach for your location (to check for occultations by possible satellites of Niobe). You can search for your city or name with a word processor to find your time and distance from the predicted central line. If your station is not in the list, send me the coordinates of the place where you plan to observe (in the USA, you can just specify an address or highway intersection) and I'll add that station for a later message. Please let me know if you plan to monitor the star for an occultation, and I will send out a new version of this list with your track marked as occupied. This will help for positioning mobile observers. I will put items in the "C" (code) column, to indicate commitments to observe from fixed sites and weather probabilities. NOTE: The table needs to be displayed and/or printed with a fixed- space font such as Courier for the columns to line up properly, and with a small font, possibly 8 or 9 point, to prevent line wrapping. In the e-mail message, the lines are long enough that some (or many) of the lines will wrap; I will place a .txt (plain ASCII text) version of this during the afternoon on my Web site at http://iota.jhuapl.edu . As can be seen from the list, observers some distance from the path have a chance to see the occultation, and observers at least within the +/-2-sigma range (distance 251 km N. to 251 km S.) are strongly encouraged to attempt observation. Under C, in the next list I will put * for a committed fixed-site observer, V = * with video, and m = tentative location for mobile observer, and M = tentative location for mobile video observer. W = V or M that will probably be clouded out, while w = * or m that will probably be clouded out; for these, don't count on their coverage, but if mobile, try not to set up right at their chord just in case they get a lucky break in the clouds. Feb. 10 Dist. U.T. W.Long. Lat. h City/ State/ Observer or km C h m o o m Town Country Observatory 219E 5 56.6 90.341 38.585 152 ST. LOUI MO WAYNE E. CLARK 218E 5 56.1 91.191 43.808 366 LaCrosse WI Robert Allen 217E -- Eastern limit with very unlikely 3-sigma east shift 216E 5 56.0 91.272 44.816 285 FallCrek WI C14, U. of Wisconsin 215E 5 56.6 90.379 38.474 485 ST. LOUIS MO JOHN DUCHCK 199E 5 56.0 91.499 44.796 268 EauClair WI U. of Wisconsin 183E 5 55.9 91.753 45.696 372 Sarona WI Al Timblin 179E 5 56.9 89.899 35.255 76 MEMPHIS TN JAMES E. HONEY 170E 5 56.3 91.616 42.054 262 Marion IA John Centala 168E -- Eastern limit with unlikely but possible 2-sigma east shift 167E 5 56.3 91.659 42.049 261 CEDAR RA IA FRANK OLSEN 166E 5 56.3 91.653 42.011 0 CedarRpd IA Larry Black 165E 5 56.3 91.675 42.020 0 CedarRap IA HillsideO D.Plasencia 164E 5 55.8 92.015 46.875 400 Duluth MN Bob King, 10"L,vis. 163E 5 57.1 89.385 33.288 0 FrnchCmp MS c/o Scott Degenhardt 161E 5 56.3 91.692 41.848 0 Swisher IA OwlRidgeO DougSlauson 158E 5 55.8 92.093 46.818 383 Duluth MN Douglas Dunham 126E 5 56.9 90.717 35.827 99 JONESBOR AR PAUL QUALTIERI 119E --5 56.9 90.728 35.619 0 ** 1sigma e.limit, occ'n very possible 110E 5 56.3 92.440 42.520 0 CedarFal IA Tom Hockey 91E 5 56.0 92.924 44.829 0 AFTON MN JAMES H. FOX 90E m 5 56.9 90.999 35.390 0 Hickory AR Tillman Kennon 90E 5 56.7 91.768 37.936 305 ROLLA MO JOSEPH SENNE 79E 5 56.3 92.719 41.756 325 Grinnell, Iowa Bob Cadmus 74E 5 56.1 93.129 44.499 288 Northfield, MN HarvestMoonOb SteveMessner 71E 5 56.7 92.133 38.517 0 Jefferson City, MO Timothy Wilson 70E --5 56.9 91.382 35.847 0 **** predicted eastern limit **** 69E 5 56.0 93.217 44.980 0 St. Paul MN Peter Santi 68E 5 56.0 93.237 44.978 0 Mineapolis MN Univ. Minnesota Obs. 63E 5 57.2 90.183 32.333 0 RidgelandMS SPEER-LYELL Ob.c/oDeg. 50E 5 57.2 90.297 32.255 0 JACKSON MS BENNY J. ROBERTS 48E 5 56.2 93.370 43.650 0 AlbertLeaMN Ken Fiscus 46E 5 56.0 93.515 44.914 305 MINNETOK MN DAVID SEVERSON 25E 5 56.3 93.430 42.030 0 Nevada IA George Forsyth 20E 5 56.0 93.874 45.172 0 Buffalo MN Baker, Mike 4-in (+sum. 15E 5 56.3 93.569 42.093 317 AMES IA DAVID OESPER 11E 5 56.3 93.617 42.033 305 AMES IA SAMUEL WORMLEY 8E 5 56.3 93.627 41.997 0 Ames IA Robin Formaker 0E 5 56.4 93.667 41.624 305 DES MOIN IA JOE GALLOWAY 0 --5 56.9 92.302 36.154 0 Center ****** UT 05:56:54 test o.k. 16W 5 56.4 93.941 42.006 333 Boone IA Fick Obs., Iowa St. 23W 5 57.4 90.119 29.939 3 NewOrleans LA Cunningham Ob. 58W 5 56.7 93.737 38.776 250 n.Warrensburg,MO Hwy 13 & US 50 59W 5 56.7 93.767 38.829 250 ICSTARS S.P., MO Rob Robinson 70W --5 56.9 93.205 36.441 0 * predicted w.limit (Hipparcos e.lim.) 90W 5 57.4 91.078 30.397 20 US M254 VID 20030111 Peter Lazar 91W 5 57.4 91.071 30.346 17 19991210 Walt Cooney, Baton Rouge, LA 98W 5 57.4 91.178 30.412 31 BatonRogue LA LSU Obs, W. Coskrey 98W 5 57.0 93.140 35.280 0 RUSSELLVILLE AR 102W 5 56.7 94.310 39.020 0 Lake Tap'go, MO Landingham, Dick 104W W 5 56.7 94.345 39.028 236 BLUE SPRINGS MO ROBERT L. SANDY 119W --5 56.9 93.828 36.630 0 ** 1sigma w.limit, occ'n very possible 131W 5 56.7 94.655 39.027 308 MISSION KS J. DENNIS BREWER 134W 5 56.7 94.598 38.667 298 Cleveland MO Tom Martinez, C8 143W 5 56.7 94.700 38.646 325 Louisburg MO Powell Obs. 30", ACKC 143W 5 56.7 94.806 39.048 297 BONNER SPRINGS WALTER L. ROBINSON 166W 5 57.0 94.170 36.070 0 FAYETTEVILLE AR 168W -- Western limit with possible 2-sigma west shift 205W 5 57.2 93.850 33.950 0 Nashville, AR Roy Clingan 209W 5 56.5 96.100 41.250 350 Omaha NE approximate 216W 5 55.8 97.074 47.922 457 GRAND FORK ND MICHAEL GAFFEY 217W -- W. Limit with 3-sigma west shift = Hipparcos Western limit 218W 5 55.6 97.121 49.645 208 Glenlea MB Scott Young 219W 5 55.6 97.131 49.811 239 Ft.Garry MB Chris Brown 220W 5 55.6 97.133 50.100 400 Lockport MB Enns, Ernest, 8-in. Dob 221W 5 55.6 97.153 49.599 236 Winnipeg MB Chris Brown 222W 5 56.7 95.703 39.021 280 TOPEKA KS CRAIG A. MCMANUS 222W 5 56.8 95.393 37.922 0 Iola KS Tom Campbell 226W 5 56.7 95.750 39.000 451 TOPEKA KS REX EASTON 230W 5 55.5 97.250 50.383 259 Teulon, MB Gerry Smerchanski, C8 231W 5 56.8 95.691 38.608 400 Lyndon, KS HART 232W 5 55.6 97.293 50.136 229 1997 610 Patrick O'Connor, Pinawa, MB 239W 5 56.8 95.630 38.090 350 Le Roy, KS C. & T. McManus 243W 5 57.3 93.621 32.329 49 Shreveport LA Krajci Email bad 244W 5 57.2 94.176 33.669 0 Ashdown, AR Walter Webb 251W 5 56.7 96.001 38.890 400 Eskridge, KS Farpt.Obs..3m,Gary Hug 253W 5 56.3 96.930 42.770 305 VERMILLN SD CHRIS KEATING 254W 5 57.3 93.846 32.583 0 BlanchardLA CLaude Baines 258W 5 56.7 96.099 38.960 400 near Topeka, KS HART 259W 5 56.5 96.594 40.843 354 Lincoln NE M. Gaskell & Johnson 261W 5 56.7 96.132 38.947 448 TOPEKA KS RICHARD WILDS 299W 5 57.4 93.929 31.650 107 Goober Hill, TX Rocky Harper GPS C8 vis. 302W 5 56.9 96.230 37.720 350 Climax, KS Richard Wilds 317W 5 57.1 95.500 35.084 65 Conway AR AR SkyObs,C.Sherrod 12" 415W 5 56.9 97.476 37.728 216 WICHITA KS MARTIN RATCLIFFE 435W 5 57.0 97.136 36.060 323 Stillwat OK Art Lucas 532W 5 57.6 95.606 29.933 0 nw Houston, TX Brian Cudnik David Dunham, 2005 Feb. 9, 6 pm CST (Feb. 10 1h UT) Phones home 301-474-4722; cell 301-526-5590