ASTEROIDAL OCCULTATION - REPORT FORM +------------------------------+ +------------------------------+ | EAON | | IOTA/ES | | | | INTERNATIONAL OCCULTATION | | EUROPEAN ASTEROIDAL | | TIMING ASSOCIATION | | OCCULTATION NETWORK | | EUROPEAN SECTION | +------------------------------+ +------------------------------+ 1 DATE: 29 October 2019 STAR: TYC 1932-00469-1 (10.1 mag) ASTEROID: Sylvia (+Remus) No: 87 2 OBSERVER: Name: Marek Zawilski Abbr: Address: 91-473 Lodz, Poland 3 OBSERVING STATION: Nearest cities: Lodz and Poddebice Station: Tobolice Latitude: 51d 54' 48.3" N Longitude: 19d 03' 22.4" E Altitude: 140m MSL Datum (WGS84 preferred): WGS84 Single, OR Double or Multiple station (Specify observer's name): SINGLE +----------------------------------+ 4 TIMING OF EVENTS: | | | OCCULTATION RECORDED: NEGAITIVE | | | +----------------------------------+ Type of event Start observation Interrupt-start Disappearance Blink Flash End observation Jnterrupt-end Reappearance Other (specify) Comments Event Time (UT) P.E. Acc. Code HH:MM:SS.ss S.ss S.ss S - 23:37:00 - N/A - 1 : D - - : R - - : E - 23:41:00 - N/A - 1 : Duration : no occultation for sure, also no effect for possible Remus' occultation Mid-event : Predicted mid-event : 29 Oct; 23:39:34 UT +/- 2 sec Was your reaction time applied to the above timings? N/A 5 TELESCOPE: Type: Cassegrain Aperture: 203mm Magnification: --- Mount: Equatorial Motor drive: YES Foc.length: 2032mm reduced to 1016mm 6 TIMING & RECORDING: Time source: NTP via Dimension4 using the time server "tempus1.gum.gov.pl",Warsaw, laptop-time synchronized better than 0.01s, response of about 10 Polish ntp time servers checked evry one minute with the use of the professional software by T.Kluwak, regarding the time offset and resopose delay (both of very low value and stable - offset +0.03s, delay 0.02s at 23:39-23:40); Sensor: ZWO ASI 120MM, shutter set for 300 ms, image resolution 1024x968 px, gain 100 (star faint due to thin fog). Recording: ASICAP v.1.6.1 software 7 OBSERVING CONDITIONS: Atmospheric transparency: good Wind: none Temperature: -2 deg C Star image stability: good Minor planet visible: yes (with the 3s shutter 30-20 min prior to occultation) 8 ADDITIONAL COMMENTS: The light curve analyze using Tangra software and a careful inspection of the screen replay showed no remarkable drop of star brightness both caused by Sylvia and Remus. The sky was very clear, however, a thin fog appearing during the mid-time caused the need to increase of the shutter from 100 to 300 ms. Despite this the star image was stable both for the occulted and guiding star. Predicted max 23.0 sec duration with 3.3 mag drop. Event probability at site : 33.5% Distance from center line : 254 km in S-E direction Local * conditions (Alt,Az): 30°, @84°