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ASTEROIDAL OCCULTATION - REPORT FORM

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EAON & IOTA-ES

EUROPEAN ASTEROIDAL OCCULTATION NETWORK

INTERNATIONAL OCCULTATION TIMING ASSOCIATION EUROPEAN SECTION

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1. DATE: 25 Aug 2022
   STAR: UCAC4 350-187717
   ASTEROID: (928) Hildrun

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 - 20:00:00
D - 20:03:13.7 ± 0.4 sec
R - 20:03:19.1 ± 0.3 sec
E - 20:06:00

   Duration: 5.4 ± 0.7 sec

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. 4.0.8395 software, saved on SSD as SER file
   -binning = 2x2, sensor cooled, sensor temperature = 0 °C, camera bit depth = MONO16, area size in pixel = 960x600, USB traffic = 5, setted exposure = 500 ms, gain = 480, offset = 0, contrast = 0, brightness = 0, gamma = 1, banding suppression = 47, banding threshold = 85, apply flat = none, subtract dark = none
   -Timekeeping: GPS UTC clock
   -Integration time: 0.500 s

7. OBSERVING CONDITIONS
   
   -Atmospheric transparency: fair/good
   -Wind: no 
   -Star image stability: fair/good
   -Minor Planet visible during the occultation: barely

8. ADDITIONAL COMMENTS
   
   Prediction:
   -Occultwatcher, IBEROC feed
   -Rank: 100
   -Probability: 21.5 %
   -Combined magnitude: 14.1 mag
   -Star magnitude: 14.5 mag V; 14.2 mag R
   -Asteroid magnitude: 15.4 mag
   -Lightdrop: 1.29 mag; 1.2 mag R
   -Max duration: 4.9 s
   -Event time: 20:03:16 UT
   -Error in time: 2 s
   -Moon distance: -
   -Moon illumination: -
   -https://cloud.occultwatcher.net/event/601-928-289932-646742-U187717

   Other comments:
   -Target sky position: elevation = 20 deg, azimut = 155 deg
   -Tangra v. 3.7.3 was used to generate the lightcurve (aperture photometry, average background). Time reference: Start Frame 
   -Measured Lightdrop: ~ 1.5 mag
   -Eric Frappa checked and refined the analysis with AOTA v. 4.2022.18
   -Measured mid-event time: 20:03:16.4 UT   
   -The lightcurve can be seen here:
http://sposetti.ch/wp-content/uploads/2022/08/2022_08_25_Hildrun_Gnosca.png