ASTEROIDAL OCCULTATION - REPORT FORM- CORRECTIF 1 +------------------------------+ +------------------------------+ | EAON | | IOTA/ES | | | | INTERNATIONAL OCCULTATION | | EUROPEAN ASTEROIDAL | | TIMING ASSOCIATION | | OCCULTATION NETWORK | | EUROPEAN SECTION | +------------------------------+ +------------------------------+ 1 DATE: 2019 July 11 STAR: UCAC4 311-163008 ASTEROID: 257 SILESIA 2 OBSERVER: Name: Gérard VAUDESCAL Abbr:VDC E-mail: gg.vaudescal@free.fr Address: 65380 Azereix - France Name: Pascal DUBARRY Abbr: E-mail: Address: ASS. DINASTRO 3 OBSERVING STATION: Nearest city: VISKER(65200) Station: Observatoire de Biscarmiau Latitude: N 43 08 40.4 (WGS84) Longitude: E 00 03 31.8 (WGS84) Altitude: 488 m Single, OR Double or Multiple station (Specify observer's name): Single +----------------------------------+ 4 TIMING OF EVENTS: | | | OCCULTATION RECORDED: POSITIVE | | | +----------------------------------+ Type of event Start observation Interrupt-start Disappearance Blink Flash End observation Jnterrupt-end Reappearance Other (specify) Comments Event Time (UT) Acc. Code HH MM SS.ss S.ss S - 21:43:07.75 on frame n°18 (correction Gerhard Dangl) D - 21:43:43.62 +/-2.56s frame n°33 " R - 21:43:50.02 +/-1.28s frame n°35 -0/+1 " E - 21:44:19.43 on frame n°46 " Duration : 6.4s +/-2.86sec Mid-event : 21:43:46.82 +/-1.9s Was your reaction time applied to the above timings? NO 5 TELESCOPE: Type: NEWTON Aperture: 305 mm Magnification: Focus 1188 mm Mount: Equatorial Motor drive: YES 6 TIMING & RECORDING: Time source: GPS 1 PPS Sensor: CAMERA WATEC 910HX/RC CCIR - integrated Shutter Low x128 (2,56sec/f) - Gamma 1 - Gain Mid Recording: OccuRec V 3.2.0 Beta and Grabber Lindy USB2 - mode AAV - Intégration rate x64 Time insertion (specify):IOTA VTI V3 (CCIR) Event insertion (specify): PC-Windows7 7 OBSERVING CONDITIONS: partly overcast Wind: 0 ms Temperature: 15 °C Star image stability: medium Minor planet visible: Yes 8 ADDITIONAL COMMENTS: Reduction under TANGRA 3.6.18 The conditions of this observation required a significant exposure time. Nevertheless, the luminous flux clearly indicates an occultation but with a low accuracy of dating. There is also a significant lag of the event compared to the forecast: 21:43:46.82 +/-1.9s for a forecast of 21:43:28 +/-4s. An incident Occurec need a recovery of the dates directly on the video fields with non automatic application of the corrections.