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ASTERIODAL 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: 21 Apr 2018
   STAR: TYC 0408-00029-1
   ASTEROID: (130) Elektra

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 : 00:22:50
-D : 00:31:34.65 ± 0.090 s
-R : 00:31:50.89 ± 0.090 s
-E : 00:40:02

   Duration: 16.24 s ± 0.180 s

5. TELESCOPE
   
   -Type: Schmidt-Cassegrain, Celestron 8-inch
   -Aperture: 200 mm
   -Focal length: 800 mm (with focal reducer)
   -Magnification: -
   -Mount: Equatorial
   -Motor drive: Yes

6. TIMING & RECORDING
   
   -Camera/Sensor: Videocamera WAT-120N+, CCIR, 1/2"
   -Videocamera settings: Shutter mode = Slow 3, Gain = max, Gamma = LO (0.45)
   -Device of recording: Personal computer
   -Grabber: USB Imaging Source DFG/USB2-lt, composite input
   -Software: Virtualdub v. 1.10.4, saved as uncompressed AVI file
   
   -Time insertion device: KIWI-OSD with GPS Garmin 18 LVC
   -Integration time: 0.160 s

7. OBSERVING CONDITIONS
   
   -Atmospheric transparency: good
   -Wind: none 
   -Star image stability: good
   -Minor Planet visible during the occultation: barely

8. ADDITIONAL COMMENTS
   
   Prediction: 
   -Occultwatcher, IOTA feed
   -Rank: 100
   -Probability: 90 %
   -Combined magnitude: 11.3 mag
   -Star magnitude: 11.4 mag
   -Asteroid magnitude: 12.9 mag
   -Lightdrop: 1.6 - 2.0 mag
   -Max duration: 20.5 s
   -Event time: 00:31:37 UT
   -Error in time: 3 s
   -Moon distance: below horizon
   -Moon illumination: none

   Other comments:
   -Sky position of the target: elevation = 40 deg, azimut = 133 deg
   -Because of a bad recording hardware the two fields were wrongly added together. Virtualdub was used during analysis to deinterlace the fields and to reassemble the frames in the right sequence
   -Tangra v. 3.6.15 was used to reverse the gamma settings and to generate the lightcurve (aperture photometry, average background)
   -S/N of the target (before D and after R) about 7
   -A correction of - 0.110 s was applied because of the use of an integration camera ("Dangl-correction")
   -A lightcurve can be seen here:
http://sposetti.ch/wp-content/uploads/2018/04/2018_04_21_Elektra_Locarno_Sposetti.png