The Total Solar Eclipse of 2009-07-22 in Wuhan, China 

by Dr. Wolfgang Strickling

German version / diese Seite auf deutsch

	Eclipse Orchestrator		Javascript Calculator
	UTC	CST (=UTC +8h)	CST	Azimuth	Elevation	Shadow bands orientation	Azimuth of centerline
1st Cont.	00:14:59	08:14:59	08:14:57.1	84°	32°
2nd Cont.	01:24:07	09:24:07	09:24:06.4	93°	47°	8°
Mid:	01:26:49	09:26:49	09:26:47.4				268° / 88°
3rd Cont.	01:29:28	09:29:28	09:29:29.6	93°	48°	161°
4th Cont.	02:46:29	10:46:29	10:46:26.4	108°	65°

All times are given here in UTC. Local Chinese Standard Time (CST) was  UTC + 8h.


With the help of Eclipse Orchestrator software i could register the phenomena at second and third contact automatically very well, without dealing with the photographic equipment. I used a Canon  Canon 450D SLR Camera and a Russian Maksutov Telephoto lens MC 3M-5CA 500 mm f/8.




A single shot of the corona. All those pictures were disturbed by the clouds, so i tried to stack them with Registax. So it is possible to take an average picture without these fast changing cloudiness patterns. The coronal structures can be enhanced by radial unsharp masks, see images below. Left is in the first third of totality, the right one is just before the end.



 



Baily's beads were very impressive, especially at third contact. Fortunately, the observation of the diamond ring and Baily's beads at second and third contact were not affected by the clouds.
Upper images are from second contact, the lower ones from third contact. The first resp. the last exposure were taken with a solar filter.
Orientation: North up. Time is given in UTC.

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Atmospheric phenomena:

The thin cirrus and altocumulus clouds showed the approach and vanishing of the lunar shadow very impressive. There were also nice dawn colors to be seen at the horizon. With an automatically triggered compact camera (Fuji F40fd), i could register a nice sequence of the lunar shadow's movement. A click onto the image left opens a small GIF animation. A video of the lunar shadow in fast motion (30x) on YouTube. Click "HQ" for best quality!




Around totality i made a sequence of 30 fisheye photographs. I used a Peleng 3,5 / 8 mm full frame fisheye lens on Fujicolor Sensia 200 ASA color print film. The sequence shows very impressive the motion of the lunar shadow in the high clouds.

You can see a Flash-animation by clicking here or clicking onto the image left. The animation runs slower at second and third contact in order to improve the visibility of the shadow.

Orientation:  North up, East is left.

An animation of the lunar shadow in fast motion (30x) on YouTube. Click "HQ" for best quality!




This Video at Youtube.

Because of the haze and the clouds, i did not see any shadow bands. I spread a white cloth on the ground and filmed it with a DV camcorder (Sony PC 100), but even a careful analysis of the video including contrast enhancement and background subtraction did not reveal any shadow bands at all. Furthermore, on one audio track i recorded the signal of a light-to-frequency converter (TSL 230), but this signal did not show any hints to shadow bands, too.

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Weather measurements:

During the eclipse, i measured temperature in 1 m height, 0.1 m and in the ground, sky brightness and wind speed with a C-Control-Pro microcontroller. I used DS1621 circuits for temperature registration, a TSL 230 for illuminance and a cup anemometer for measuring wind speed. A second device controlled a sky brightness meter, with a similar sensor like the SQM. This device was also equipped with a thermometer.

One camcorder was directed onto a white cloth in order to record shadow bands. On its stereo soundtrack, one channel recorded the signal of a light to frequency converter (also a TSL 230), which was directed towards the sun.
On this setup there was also a fisheye camera (controlled by Eclipse Orchestrator software) and the horizon camera (Fuji F40fd, not shown in the image left).

The air temperature (blue and violet) fell from ca. 35° C before the eclipse down to 31.5° C a few minutes after the eclipse. There was no eclipse wind to register during totality, similar to my measurement at other eclipses (light blue graph).

The illuminance (yellow) decreased to a minimum of appr. 4 Lux at mid-totality. This value is comparable to the dawn at a solar depression of 6 deg below the horizon under clear skies, in mid Europe about 35 to 40 minutes after sunset. It wa slightly higher than then 2.8 Lux i recorded in 1999 (France) or 2001 (Zimbabwe). I suppose, that the reason were the high but thin clouds, reflectin the light from the umbral borders into the central regions.

It was remarkable, the the crickets in the surrounding trees started a very loud chirping just before totality at 01:23:50 and stopped suddenly after 3rd contact at 01:30:00 UTC. In the graph left is shown in red the loudness curve recorded with a microphone. The increased sound level at totality is mainly a contribution of the crickets.
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Sky brightness

For registering the sky brightness i used a similar device like the  SQM, based on the hardware of the  C-Control microcontroller. The measurement values are given in magnitudes per square arc second. It used a  TSL237 circuit with a green IR-cut filter similar to the Hoya CM-500. The sensor was mounted in a tube with an angle of aperture of  30 degrees. It could be aligned to any point at the sky by a servo drive as used in model building.
I choose 9 points of interest: The zenith, points in 40° and 15 ° elevation at northern, eastern, southern and western direction.
Because of the trees in northern and eastern directions, i rejected the measurements near the horizon in those directions. The minmal value of the sky brightness was between 13.5 to 14 mag/arcsec², if we omit the direction to the sun and to the north (trees there!). Without clouds i estimate a 0.1 to 0.2  mag weaker brightness, derived from measurements of my fisheye pictures. The resulting value of appr. 14 mag/arcsec² is the same like the zenith brightness in clear skies if the sun is 6° below the horizon. 
Furthermore, you see the asymmetry of the brightness development, caused by the approaching and vanishing of the shadow.
Download here my SQM-measurements (CSV-file).

My Instruments:
Left: my weather station with cup anemometer, illumination sensor under a cylindrical light dome and the thermometer under a shield. Not shown is the ground thermometer.

Right:  The sky brightness meter with sensor, tube and two axis servo drive. In the sensor plug is an integrated thermometer circuit.

More images:
   

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Here an image of the penumbral lunar eclipse of 2009-08-06, following "our" total solar eclipse.
Left: Shot before the eclipse (some smaller clouds were passing).
Right. At maximum eclipse. You will note a slight darkening of the lower southern lunar limb. There was 40% of the lunar diameter covered by the penumbral shadow of the earth.