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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: 22 Aug 2020
   STAR: TYC 6947-00591-1
   ASTEROID: (328) Gudrun

2. OBSERVER
   
   Name: Stefano SPOSETTI
   Address: 6525 GNOSCA - Switzerland
   Email: stefanosposetti@ticino.com

3. OBSERVING STATION
   Nearest city: CH-6600 Locarno
   Station: Specola Solare
   Longitude (dd mm ss.s): 08 47 16.0 (E)
   Latitude (dd mm ss.s): 46 10 20.1 (N)
   Altitude: 368 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 : 23:08:22
-D : 23:10:35.46 ± 0.020 s
-R : 23:10:41.14 ± 0.020 s
-E : 23:12:30

   Duration: 5.68 s ± 0.040  s

5. TELESCOPE
   Type: Schmidt-Cassegrain, Celestron 8-inch
   Aperture: 200 mm
   Focal length: ~ 900 mm (with focal reducer)
   Magnification: -
   Mount: Equatorial
   Motor drive: Yes

6. TIMING & RECORDING
   -Camera/Sensor: Videocamera WAT-910HX-RC, CCIR, 1/2", ICX429ALL sensor
   -Videocamera settings: Shutter = x2 and x4; Gain = 37/41; Gamma = 1.00
   -Device of recording: Personal computer
   -Videograbber: Logilink USB Grabber VG0001, composite input
   -Software: Virtualdub v. 1.10.4, saved on Harddisk as Lagarith compressed file
   -Time insertion device: IOTA-VTI, v.1.1.42
   -Timekeeping: GPS 1PPS (US Global Sat EM-406A)
   -Integration time: 0.080 s, but mostly 0.040 s (see "other comments")

7. OBSERVING CONDITIONS
   
   -Atmospheric transparency: fair, because of thin clouds
   -Wind: none 
   -Star image stability: fair/bad
   -Minor Planet visible during the occultation: no

8. ADDITIONAL COMMENTS
   
   Prediction:
   -Occultwatcher, IOTA feed
   -Rank: 100
   -Probability: 96 %
   -Combined magnitude: 9.3 mag
   -Star magnitude: 9.3 mag V
   -Asteroid magnitude: 13.7 mag
   -Lightdrop: 4.4 mag
   -Max duration: 9.1 s
   -Event time: ~ 02:48:39 UT
   -Error in time: 3 s
   -Moon distance: -
   -Moon illumination: -

   Other comments:
   -Target sky position: elevation = 16 deg, azimut = 183 deg
   -Tangra v. 3.7.3 was used to generate the lightcurve (aperture photometry, average background)
   -Between S and E timings an integration time of 0.040 s (shutter mode = x2) was mostly used, but sometimes it was changed to 0.080 s.          -Between D and R an integration time of 0.040 s was used.  
   -D and R times were evaluated using AOTA v. 4.10.5.0
   -A time correction of -0.040 s was applied (so called "Dangl correction")
   -A lightcurve can be seen here:
http://sposetti.ch/wp-content/uploads/2020/08/2020_08_22_Gudrun_Locarno.png