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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: 2015/08/14
  STAR: 2UCAC 43054160
  ASTEROID: (54) Alexandra

2.OBSERVER:
  	Name: Gerhard Dangl
	Phone: ++43-(0)2842-53908
	Address: AUSTRIA, A-3830, Nonndorf 12
	E-mail: gerhard@dangl.at

3.OBSERVING STATION:
	Nearest city: Waidhofen an der Thaya
	Latitude:  N 48 47 13.5 (WGS84)
	Longitude: E 15 14 08.3 (WGS84)
	Altitude:  600m         (WGS84)
	Single/Multiple: Single

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4.TIMING OF EVENTS:
	Occultation recorded: NEGATIVE (corrected from first reported POSITIVE - see comments below)
	Type of event:
	"S"tart observation; "I"nterrupt-"s"tart; "D"isappearance;
	"B"link; "F"lash; "E"nd observation; "I"nterrupt-"e"nd;
	"R"eappearance; "O"ther (specify)
	
	Personal Equation Substracted: No
	Event Time (UT)		P.E. Accuracy + Comments
	code: HH:MM:SS.ss       S.ss  S.ss
	
	S:    22:15:57

	E:    22:19:40   
	
5.TELESCOPE:
	Type: Newton
	Focal length: 1200mm
 	Aperture: 254 mm
	Magnification: video/primary focus/FOV 18.3'x13.7' (768x576, 1.43"x1.43" per pixel)
	Mount: Equatorial, EQ8
	Motor drive: Yes

6.TIMING & RECORDING:
	Timekeeping: GPS Sensor Garmin GPS18xLVC
        Sensor/Camera: WAT-120N, CCIR, 1/2" Sony CCD-Sensor ICX419ALL
	Mode of recording: It=320ms (3.125 Img/s), Video CCIR, Y800, uncompressed AVI
	Device of recording: TIS DFG/USB2-lt Videograbber USB2.0 (Y800), Notebook with SSD and OS W7/64P
        Time insertion: KIWI-OSD VTI

7.OBSERVING CONDITIONS:
	Atmospheric transparency: bad
	Wind: no
	Star image stability: bad
	Minor planet visible: not separated
	Temperature: 296 Kelvin (+23 deg Celsius)
	
8.ADDITIONAL COMMENTS:
        Target star 2UCAC 43054160, +12.3mag, 14deg Elevation.
        Only Clear glass filter (Astronomik) for CCD protection was used.

        Video evaluation accomplished with VirtualDub 1.10.0 and Tangra 3.5.1

        Because of the use of a WAT-120N CCIR in integration mode Frame8 (It=320ms),
        a correction of -190ms was performed at the times inserted in the video by the VTI.
        The correction value is according to measurements results with EXposure Time Analyzer - EXTA.
        http://www.dangl.at/exta/exta_e.htm
        So all event times in this report are corrected times representing the real event times in UTC.

        Event data details according to the predictions from IOTA (Steve Preston).
        Predicted event time was 22:17:41 UTC (+/- 2s) for my observing position.
        Predicted maximum duration was 7.6 seconds with a 1.1mag drop.
        Position was 52km from predicted central line in EES direction
        between center line and path edge with a probability of 97.8%.

        The comparison with the results of other stations showed that the positive occultation event
        detected in Nonndorf with a duration of 1.600s +/-0.34s (It=0.320s) does not fit and so obviously
        was wrong due to too bad signal/ noise ratio.
        So the result of this observation was revalued and corrected to negative on September 23, 2015.
        
        3-D Position and timing
	Garmin GPS18x LVC
        Receiving 08 satellites
        Horizontal Dilution of Precision 1.1
        Geoidal separation 44.5m (Altitude 555.2MSL + 44.5 = 599.7 m in WGS84 datum)

        Gerhard Dangl
        gerhard@dangl.at
        www.dangl.at/
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