+--------------------------------+ +--------------------------------+ ASTEROIDAL OCCULTATION - REPORT FORM +--------------------------------+ +--------------------------------+ EAON & IOTA-ES EUROPEAN ASTEROIDAL OCCULTATION NETWORK INTERNATIONAL OCCULTATION TIMING ASSOCIATION EUROPEAN SECTION +--------------------------------+ +--------------------------------+ 1. DATE: 18 Feb 2020 STAR: UCAC4-496-004715 ASTEROID: (393) Lampetia 2. OBSERVER Name: Stefano SPOSETTI Address: 6525 GNOSCA - Switzerland Email: stefanosposetti@ticino.com 3. OBSERVING STATION Nearest city: CH-6525 Gnosca Station: 143 (MPC-code) Longitude (DD MM SS.s): 09 01 26.5 (E) Latitude (DD MM SS.s): 46 13 53.2 (N) Altitude: 260 m (WGS84) 4. TIMING OF EVENTS Occultation recorded: POSITIVE Type of event: "S"tart observation; "I"nterrupt-start; "D"isappearance; "B"link; "F"lash; "E"nd observation; "I"nterrupt-end; "R"eappearance; "O"ther (specify) Personal Equation Substracted: - Event Time (UTC) Accuracy + Comments code: HH:MM:SS.ss S.sss -S : 18:48:57 -D : 18:53:11.342 ± 0.050 s -R : 18:53:16.504 ± 0.050 s -E : 18:56.47 Duration: 5.16 s ± 0.100 s 5. TELESCOPE -Type: Newton -Aperture: 420 mm -Focal length: 1640 mm -Mount: Equatorial -Motor drive: Yes 6. TIMING & RECORDING -Camera/Sensor: Videocamera QHY174M-GPS, SONY IMX174 CMOS sensor -Device of recording: Personal computer, USB3 input, SharpCap PRO v. 3.2.6173.0 software, saved on SSD as SER file -binning = 2x2, uncooled, camera bit depth = 8, pixel image size = 960 x 600, USB Traffic = 0, setted exposure = 50 ms, Gain = 480, Offset = 0, Contrast = 0, Brightness = 0, Gamma = 1 -Timekeeping: GPS UTC clock -Integration time: 0.050 s 7. OBSERVING CONDITIONS -Atmospheric transparency: good -Wind: none -Star image stability: fair -Residual light visible during the occultation: yes 8. ADDITIONAL COMMENTS Prediction: -Occultwatcher, IOTA feed -Rank: 100 -Probability: 21.1 % -Combined magnitude: 12.3 mag -Star magnitude: 12.5 mag V -Asteroid magnitude: 14.2 mag -Lightdrop: 1.9 mag -Max duration: 6.2 s -Event time: 18:53:16 UT -Error in time: 2 s -Moon distance: - -Moon illumination: - Other comments: -Target sky position: elevation = 44 deg, azimut = 225 deg -Tangra v. 3.6.23 was used to generate the lightcurve (aperture photometry, average background) -Time reference used in Tangra: start frame -S/N ratio ~ 5 during pre- and after- event -The expected luminosity drop of ~ 2 mag was not observed -Signal drop: from 791 ADU to 493 ADU (calculated averages); the calculated drop was therefore 0.51 mag -D and R uncertainty times were doubled -Measured mid-event UT time: 18:53:13.92 -Accordingly to Occultwatcher my location was inside the 1-sigma zone -A lightcurve can be seen here: http://sposetti.ch/wp-content/uploads/2020/02/2020_02_18_Lampetia_Gnosca.png