Grazing star occultation by the Earthmoon on June 13, 2009
SAO 164408

Seite in Deutsch

Frameless version of this page

On June 13, 2009 at about 02h01 UTC the Earthmoon grazed the star SAO 164408 in a height of 26 degrees above the southeast horizon with the dark area of the moon northpol. Thereby the star was occulted and became visible several times by the moon mountaines and moon valleys on the moon horizon. Despite of ground fog 10 occultation events, with two of them gradual, could be recorded on video.

The earthmoon grazes the star SAO 164408 Diagram created with Guide 8 from Bill J Gray

The moon profil at the calculated graze point Diagram created with Occult 4 from Dave Herald

This grazing star occultation on the dark moon area was captured with my equipment with a relative high accuracy of some milliseconds and evaluated later.

Diagram of equipmennt setup

The path of the grazing star occultation runs cross through Europe

The calculation of the observation point was done in a self made table sheet

Position elevation and moon profil require a double parallel shifting of the observation point (OP) Correction of observation point = (-842m) + (-963m) = -1805m shift to the green line for 0m above sea level

Aerial image of the calculated observation place west from Eulenbach - in northern Woodquarter Observation position 48° 47´ 08.6" North, 15° 07´ 59.9" East

The observation place and all the region around was covered by ground fog

Because of the high IR sensitivity of the WAT-902H2 Ultimate video camera the star SAO 164408 with +8.1mag could be hold visible on the moon limb. Overall 12 events were recorded during this grazing star occultation.

The ground fog was no problem for the WAT-902H2 Ultimate video camera

Observations during dawn are often accompanied by ground fog

 

Observation report

Date                         Observer Position - 3902 Eulenbach            Observer
2009/06/13                   48°  47´  08.6"  North  (WGS84)               Gerhard Dangl
Star                         15°  07´  59.9"  East   (WGS84)               3830, Nonndorf 12
SAO 164408, +8.1mag          553m (MSL),      597m   (WGS84)               AUSTRIA


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 EQ6 with EQMOD
	Motor drive: Yes

TIMING & RECORDING:
	Timekeeping: GPS 1PPS Garmin18 LVC + KIWI-OSD
        Sensor/Camera: WAT-902H2 Ultimate, CCIR, 1/2" Sony CCD-Sensor ICX419ALL
	Mode of recording: It=20ms (50 Img/s), Video CCIR, AVI, YUY2, Huffyuv,
	Device of recording: TIS DFG/USB2-lt Videograbber USB2.0, Notebook Harddisk
        Time insertion: KIWI-OSD

OBSERVING CONDITIONS:
	Atmospheric transparency: fair (ground fog)
	Wind: No
	Star image stability: fair
	Temperature: 277 Kelvin (+04 deg Celsius)

ADDITIONAL COMMENTS:
	Predictions with Occult4
        WAT-902H2 Ultimate with manual cable gain control.
	Video evaluation accomblished with VirtualDub1.8.5
        Only clear glass filter (Astronomik) for CCD protection was used
        3-D position and timing with Garmin GPS18 LVC receiving 09 satellites, Horizontal dilution of precision 1.0
        Geoidal separation 44.5m (Altitude 552.7MSL + 44.5 = 597.2 m in WGS84 datum)
        Position shift calculations:
        Correction for MSL 517m: - 842 meters (path calculated for Mean Sea Level=0m)
        Correction for profile :  -963 meters
        Observation point (OP) : -1805 meters