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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: 11 Feb 2020
   STAR: UCAC4 656-025849
   ASTEROID: (22694) Tyndall

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

-S1 : 17:35:30
-E1 : 17:38:12
-S2 : 17:38:18
-D :  17:38:33.806 ± 0.020 s
-R :  17:38:34.287 ± 0.020 s
-E2 : 17:41:30

   Duration: 0.481 s ± 0.040 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 = 976 x 611, USB Traffic = 5, setted exposure = 40 ms, Gain = 480, Offset = 0, Contrast = 0, Brightness = 0, Gamma = 1
   -Timekeeping: GPS UTC clock
   -Integration time: 0.040 s
  
7. OBSERVING CONDITIONS
   -Atmospheric transparency: good
   -Wind: some wind in the observatory
   -Star image stability: bad, strong turbulence
   -Minor Planet visible during the occultation: no

8. ADDITIONAL COMMENTS
   Prediction:
   -Occultwatcher, ITALOccult feed
   -Rank: 6
   -Probability: 3.4 %
   -Combined magnitude: 11.5 mag
   -Star magnitude: 11.5 mag V; 10.5 mag R
   -Asteroid magnitude: 18.2 mag
   -Lightdrop: 6.7 mag; 7.2 mag R
   -Max duration: 0.9 s
   -Event time: 17:38:37 UT
   -Error in time: 10 s
   -Moon distance: -
   -Moon illumination: -
 
   Other comments:
   -Target sky position: elevation = 76 deg, azimut = 104 deg
   -Tangra v. 3.6.22 was used to generate the lightcurve (aperture photometry, average background)
   -Time reference used in Tangra: start frame
   -S/N ratio ~ 5.5 during pre- and after- event
   -Signal dropped from ~ 1400 ADU to ~ 190 ADU
   -Measured mid-event UT time: 17:38:34.05
   -Accordingly to Occultwatcher my location was in the 1-sigma zone, 15 km outside the shadow path
   -A lightcurve can be seen here:
http://sposetti.ch/wp-content/uploads/2020/02/2020_02_11_Tyndall_Gnosca.png