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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: 23 Oct 2017
   STAR: TYC 0638-00660-1
   ASTEROID: (154) Bertha

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

3. OBSERVING STATION
   Nearest city: CH-6525 Gnosca
   Longitude: 9d 1m 26.5s (E)
   Latitude: 46d 13m 53.2s (N)
   Altitude: 260m
   (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 : 02:29:28
-D : 02:29:48.599 ± 0.010 s
-R : 02:29:59.889 ± 0.010 s
-E : 02:35:42

   Duration: 11.290 s ± 0.020 s

5. TELESCOPE
   -Type: Schmidt-Cassegrain, Celestron 11-inch
   -Aperture: 280 mm
   -Focal length: 930 mm (with focal reducer)
   -Magnification: FOV 23x18 arcmin
   -Mount: Equatorial
   -Motor drive: Yes

6. TIMING & RECORDING
   -Sensor/Camera: Videocamera WAT-910HX-RC, CCIR, 1/2", ICX429ALL sensor
   -Videocamera settings: Shutter = 1/50s; Gain = 35/41; Gamma = 1.00
   -Device of recording: Personal computer, Imaging Source DFG/SV1 PCI, composite input, Virtualdub acquiring software, saved on Harddisk as compressed Huffyuv file
   -Timekeeping: GPS 1PPS (US Global Sat EM-406A)
   -Time insertion device: IOTA-VTI, v.1.1.42
   -Integration time: 0.020 s (frames deinterlaced into fields)

7. OBSERVING CONDITIONS
   -Atmospheric transparency: good
   -Wind: moderate 
   -Star image stability: fair
   -Minor Planet Visible during the occultation: -

8. ADDITIONAL COMMENTS
   -Because of a technical problem the video capture could start only some seconds before the disappearing
   -Target position at: azimut = 240 deg; elevation = 43 deg
   -Moonlight: none

   Accordingly to Occultwatcher prediction (IOTA feed):
   -Rank: 100
   -Probability: 79.2 %
   -Combined magnitude: 10.0 mag
   -Star magnitude: 10.2 mag
   -Asteroid magnitude: 12.5 mag
   -Lightdrop: 2.4 mag
   -Max duration: 11.7 s
   -Event time: 04:29:54 UT
   -Error in time: 2 s
   -Moon distance: under the horizon
   -Moon illumination: none

   -Virtualdub v. 1.10.4 was used to deinterlace the avi frames. Deinterlacing method: bob.
   -Tangra v. 3.6 was used to generate the lightcurve (aperture photometry, average background).
   -A correction of -0.020 s was applied because of the use of an integration camera.
   -A lightcurve can be seen here:
   http://sposetti.ch/wp-content/uploads/2014/09/20171023_Bertha_Gnosca.png