Occultation by (152) Atala May 6 Well-Observed
Nine positive chords were fairly well-distributed across the asteroid with negative observations also near both limits
Updated: 2006 May 31
From: David Dunham [dunham@starpower.net] Sent: Wednesday, May 31, 2006 1:03 AM To: Dunham, David Subject: Now 8 Atala chords timed, & close misses north and south Need to add to this Gary Frishkorn's video obs., & Tolea's miss Observations of the occultation of TYC 5558-01048-1 by 152 Atala show that the path shifted only about 0.3 sigma north, according to the second summary below, now with 8 positive chords reasonably well-spaced across Atala, and two close miss observations near both of the actual limits. Steve Preston's 05/05/06 update [the LATEST update] Occultation of TYC 5558-01048-1 by 152 Atala on 2006 May 07 (06 EDT) Distance from the center of occultation path - in km % Proba- Location km bility 115 16 ** Northern limit plus 1-sigma, occultation quite possible ** 80 F 32 Essex MD Dale Lehman - No occultation (miss) 79 32 Baltimore MD Alin Tolea - No occultation (miss) 59 42 Dayton MD Gary Frishkorn - video, 2.8s occultation 61 ? 43 Morgntwn WV TomchinObsLittleton - about 3s occ'n, visual 60 F 44 Columbia, MD Don Gardner - video, 3.4s occultation 55 46 *** Predicted Northern limit *** 51 ? 48 GRINNELL IA GRINNELL COLLEGE - photoelectric, 3.6s occ'n 43 F 52 GORF16IN Wayne H. Warren Jr. - visual, 3.7s occultation 38 F 54 GREENBELT MD Joan Dunham - video, 4.1s occultation 0 63 **** Predicted Centre Line **** 0 F 63 Jose Ripero near Madrid, Spain visual, 3s occultation -12 M 62 n.w. La Plata, MD Dunham remote - video, 3.0s occultation -21 M 61 Chapel Pt. St. Park, MD Joe Sedlak - visual, 2.7s occ'n -35 M 56 Dahlgren, VA D. Dunham mobile - video, prob. no occultation -55 46 *** Predicted Southern limit *** After reviewing my video tape at Dahlgren, VA closely, the target star was recorded. Just before the occultation, I realized that the drive was not working, and at the time of the occultation, as reported by Joe Sedlak nearby, I was carefully adjusting the telescope (at about the time of possible disappearance, the target star was close to the right edge of the field and would have exited a second or two later if I had not adjusted), but slowly enough that the target star remained visible during the adjustment. However, it was only marginally visible then with my 5" SCT (it was more clearly visible in the 8" SCT recordings at Greenbelt and at La Plata), and I could have missed detecting a short occultation, of a quarter of a second duration or less. Perhaps with some more sophisticated analysis of the tape, a short event might be revealed, or more likely found not to exist. We have collected I believe all the available timings and coordinates, and have made a first analysis of Atala's outline. That will be documented here when time permits. It looks like Atala was a little smaller than predicted, especially in the direction of motion. Thanks for all who tried to observe this occultation. Extensive predictions and plans to observe the occultation are here. __________________________________________________ David Dunham, IOTA 2006 May 31 phones home 301-474-4722; office 240-228-5609; cell 301-526-5590 Home (IOTA) e-mail dunham@starpower.net