Earthmoon occults star Regulus on daylight sky

Sunday, October 07, 2007

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On Sunday, October 07, 2007 the Earthmoon (14% lit) occulted star Regulus. In Austria - Woodquarter region - the occultation happened on southeast sky in an elevation of 41 degrees. In Woodquarter this occultation was a total one on daylight sky. The star disappeared behind the bright side of the moon disk at 05h32 UTC and reappeared about 36 minutes later at 06h08 UTC on the dark moon limb. At this time the sun was in an elevation of more than 9 degrees on southeast sky and in a distance of only 44 degrees to the moon.

In a small zone across europe of few kilometers width this star occultation could be observed as a grazing one. There the star can disappear behind moon mountains and reappear through moon valleys several times.

About this grazing occultation an extra page exist with Data and interactive map about the path across Europe. 

Data table for total occultation in Woodquarter (all times in UTC)
Occultation Predictions for Nonndorf in Oktober 2007
E.Long.   15 14  8.2   Lat.  48 47 13.5   Alt. 590m.   T.dia 250mm.   dMag 0.0

      day  Time   P   Star  Sp  Mag    % Elon Sun  Moon   CA   PA  VA  WA Libration   A   B   RV   Cct   R.A. (J2000)  Dec
 y  m  d  h  m  s      No  D       V  ill     Alt Alt Az   o    o   o   o   L    B   m/o m/o "/sec   o  h  m   s    o  m  s
07 10 07  5 32  9 D    1487SB7  1.4   14-  44   3 41 126 -39N  60  93  41 +6.7 -0.4 +2.0+3.9 .194  +61 10  8 22.3  11 58  2
      1487 = Regulus = alpha Leonis                
      1487 is triple :   1.3  8.1  175"  308.0 :   1.3       217"  274.0
Graze of 1487SB7 nearby at Lat = +51.00 -0.25(E.Long -15.24), CA = -10.6N
      07  5 50 16 Gr   1487SB7  1.4  14-  44   6 42 132
Closest distance to graze path is 229km at azimuth 22
07 10 07  6  8 35 R    1487SB7  1.4   14-  44   9 46 136  17N   3  31 344 +6.6 -0.4 +0.2-4.1 .189 +119 10  8 22.3  11 58  2
      1487 = Regulus = alpha Leonis                
      1487 is triple :   1.3  8.1  175"  308.0 :   1.3       217"  274.0
Table created with Occult3.6 from Dave Herald.

The occultation of Regulus in northern Austria at 48.79° North, 15.24° East
Occultation of Regulus in Woodquarter
Diagram created with Guide 8 from Bill J Gray

3D - Diagrams of disappearance on the bright moon limb
3-D Diagram of disappearance   3-D Diagram of disappearance
Diagram of disappearance
 
 
3D - Diagrams of reappearance on the dark moon limb
3-D Diagram of reappearance   3-D Diagram of reappearance
Diagram of reappearance

Diagrams created with software Limovie0927 from Kazuhisa Miyashita.

Videos of Regulus daytime occultation - 2007/10/07

Earthmoon moving to Regulus during local sunrise - time lapse video MPEG4 (6.5MB)

Regulus disappearance on bright moon limb - real time video MPEG4 (1.8MB)

Regulus reappearance on dark moon limb - real time video MPEG4 (1.8MB)

Diagram of used equipment setup

Some additional images from the observation beside our house
Observation image 1   Observation image 2   Observation image 3
 
Observation image 4   Observation image 5   Observation image 6

Report about Regulus occultation 2007/10/07 

+--------------------------------+ +--------------------------------+

    INTERNATIONAL OCCULTATION TIMING ASSOCIATION EUROPEAN SECTION

+--------------------------------+ +--------------------------------+

1.DATE: 2007/10/07
  STAR: ZC1487 = SAO 98967 = Regulus = alpha Leonis
  BODY: Earthmoon

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/Thaya
	Latitude:  N 48 47 13.4 (WGS84)
	Longitude: E 15 14 08.5 (WGS84)
	Altitude:  593m         (WGS84)
	Single/Multiple: Single

+--------------------------------------------------------------------+

4.TIMING OF EVENTS:
	Occultation recorded: POSITIVE
	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:    05:03:08

        D:    05:32:07.614           0.01       daytime, bright limb
        R:    06:08:35.340           0.01       daytime, dark limb    
                                                Duration 00:36:27.726  (+/-20ms)

        E:    06:09:44    
	
5.TELESCOPE:
	Type: Newton
	Focal length: 1200mm + Powermate2.5x = 3000mm
 	Aperture: 254 mm
	Magnification: video/primary focus/FOV 6.3'x5.5'/0.59"x0.57" per pixel
	Mount: Equatorial
	Motor drive: Yes

6.TIMING & RECORDING:
	Timekeeping: GPS 1PPS Garmin 18 LVC + KIWI-OSD
        Sensor/Camera: WAT-902H2 Ultimate, CCIR, 1/2" Sony CCD-Sensor ICX429ALL
	Mode of recording: It=20ms (50 Img/s), Video CCIR, AVI, YUY2, Huffyuv,
	Device of recording: Xpert V-Stream Videograbber USB2.0, Notebook Harddisk
        Time insertion: KIWI-OSD 

7.OBSERVING CONDITIONS:
	Atmospheric transparency: fair
	Wind: No
	Star image stability: fair
	Temperature: 276 Kelvin (+03 deg Celsius)
	
8.ADDITIONAL COMMENTS:
        Video evaluation accomblished with VirtualDub1.6.16 and Limovie0927

        Daylight occultation, local sunrise at 05:07 UTC
        Target star Regulus, +1.4mag, 41deg Elevation

        Clear glass filter for CCD protection and
        Planet IR Pro 807nm (both Astronomik) were used.

        3-D Position and timing
	Garmin GPS18 LVC
        Receiving 08 satellites
        Horizontal Dilution of Precision 1.1
        Geoidal separation 44.4m (Altitude 548.3MSL + 44.4 = 592.7m in WGS84 datum)

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

© 2007 G. Dangl
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