ASTEROIDAL OCCULTATION - REPORT FORM +------------------------------+ +------------------------------+ | EAON | | IOTA/ES | | | | INTERNATIONAL OCCULTATION | | EUROPEAN ASTEROIDAL | | TIMING ASSOCIATION | | OCCULTATION NETWORK | | EUROPEAN SECTION | +------------------------------+ +------------------------------+ 1 DATE: 2022/08/25 STAR: UCAC4 393-108198 ASTEROID: (339) Dorothea 2 OBSERVER: Name: Daniel BLAZEWICZ Address: 32-015 Klaj, POLAND 3 OBSERVING STATION: Klaj Nearest city: Niepolomice (Poland) Longitude: E 20 19 04.2 (WGS84) Latitude: N 49 59 33.2 (WGS84) Altitude: 211 m (MSL) Single station +----------------------------+ 4 TIMING OF EVENTS: | | | EVENT REPORTED: POSITIVE | | | +----------------------------+ Event code S: observation Start I: Interruption start D: Disappearance J: Interruption end R: Reappearance B: Blink F: Flash E: observation End O: Other (specify) Abbreviations P.E.: Personal Equation = reaction time (for visual obs) Acc.: Accuracy (overall accuracy of the given time) Comments Event Time (UT) P.E. Acc. Code HH:MM:SS.ss S.ss S.ss S - 22:11:42 - - : D - 22:14:47.80 - - 0.15 : R - 22:14:56.05 - - 0.15 : E - 22:18:25 - - : Duration : 8.25 +/- 0.21 s Mid-event : 22:14:51.92 +/- 0.11 s 5 TELESCOPE: Type: NEWTON Aperture: 350 mm Magnification: prime focus f/4.8 Mount: EQUATORIAL with polar wedge Motor drive: YES 6 TIMING & RECORDING: Time source: "chrony", 4 x NTP Stratum 1, Linux Ubuntu, 1 sigma < 1 ms Sensor: ZWO ASI174MM-C Recording: ZWO ASICAP V2.3 Exposure: 300 ms 7 OBSERVING CONDITIONS: Atmospheric transparency: fair Wind: no Temperature: 18 deg C Star image stability: poor Minor planet visible: yes 8 ADDITIONAL COMMENTS: Analyzed using Tangra v3.7.4 and AOTA v4.2022.8.18 S/N of occulted star: 3.5 - 3.6 (AOTA) Observed magnitude drop: 1.0 mag (AOTA) Camera temperature: -15 deg C Applied approximate recording delay: 14 ms (based on the report for similar hardware configuration and the same both USB setting and ROI, and similar exposure, published by Pierre Le Cam on http://www.nocturno.fr/ost/ost.html) IBEROC feed (2022/08/03): Event time: 22:14:52 UT Error in time: 6 s Max duration: 7.9 s Star magnitude: 13.5 mag Asteroid magnitude: 14.0 mag Combined magnitude: 13.0 mag Magnitude drop: 1.0 mag Position: In the shadow, 8 km from the central line Probability: 47.3 %