On 2009-07-22 i
observed the longest total eclipse of this century at the scenic
area of the East
Park in Wuhan in China.
Although the weather was not optimal for eclipse chasers, we have
had good luck an cloud observe almost the complete eclipse from
first to last contact through thin and transparent altocumulus and
cirrocumulus clouds. The second and third contact were very
impressive to observe and the horizon appeared in beautiful
colors. We enjoyed a totality of 5 Min and 21 seconds. Our WGS-84
coordinates were 30°34.220' N, 114° 22.227' E (30.5703285 N,
114.3704484 E, mean of 21 measurements). A Google-Earth image is here.
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
Orientation: North up. Time is given in UTC.
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
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
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.
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).
Weather recording around the eclipse
The graph on the left shows the illumination in Lux (yellow,
right scale) temperatures at 1 m height (blue and violet),
0.1 m (green) and in the ground (brown), and the wind
speed (light blue, averaged of 13 values) in m/s. The eclipse
contacts are marked with vertical gray lines.
Graph of temperature,
illuminance and wind speed around totality.
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.
For registering the sky brightness i used a similar device like
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
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
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.