Coronal "streamers" magnificently
framed the totally eclipsed Sun low in the sky.
(To best see low-contrast features in this image, view from at least a
meter from your screen).
The corona beyond about four solar
radii was visually obscured due to atmospheric extinction with the Sun
only 13° above the horizon and from scattering lowering
corona-to-sky contrast by very
thin, high clouds (visible in the wide-field image at the top of this
page). The structure of the corona to the full radial extent seen
was quite complex and typical of a "solar maximum" corona with
streamers radiating circumferentially at all heliocentric azimuth
angles (and it was pretty too!).
The fine-structure of the inner corona and solar limb dotted with
used also to image several prior TSEs.
The mid/outer corona (above/top) and
inner corona with prominences (above/bottom)
were imaged on 35 mm film using two synchronously exposing cameras
(Pentax ZX-30 and ZX-50). During totality, log-normal
exposure time ramps with exposures ranging
from 53 ms to 993 millisecond were executed from C2 to
mid-eclipse, and symmetrically inverted to C3 with an inter-frame
cadence of 4.3s.
Contact 2 and 3 limb phenomenon:
Baily's beads, chromosphere, and prominences (chronologicaly right to
Click HERE or on
the above image to see at 2x scale and resolution.
frame composite image. Ektar (ISO 25) film. 1200 mm f/12.
The above montage, captured as individual frames with the lug-a-scope
eclipse camera, progresses from right to left with (first) the
shrinking and breaking of the pre-totality photospheric arc into
Baily's beads and the emergence, then disappearance, of the ruby-red
chromosphere with solar prominences dotting the solar limb. The
eight composited images on the right of the totally eclipsed Sun
(showing inner corona and prominences) were exposed at -6, -4, -2, 0,
+4.3, +8.6, +12.9, and +17.2 seconds with respect to the predicted time
of second contact at 20:37:42.8 UTC. A symmetrical third
contact sequence appears to the left of the totally eclipsed Sun with
respect to the predicted time of C3 at 20:39:46.3 UTC. The image
of the eclipsed Sun is a two-farme composite from images taken +/- 19.2
seconds with respect to mid-eclipse (20:38:46 UTC) reveal the array of
prominences distributed around the periphery of the Sun visible near
the time of mid-eclipse.
Visualization of the solar
chromosphere at Contacts 2 and 3 combined.
digitally-masked, combination of four C2 and four C3 frames
from "Transition to/from Totality" sequence.
The Sun's chromosphere, an appx 20,000 km thin layer glowing in the
ruby-red (at 6563Å) light of singly ionized hydrogen atoms,
immediately surrounds the solar photosphere (1,391,000 km in diameter).
The Moon's apparent angular diameter, as seen from Maitland Downs was
appx 3.7% larger than the Sun's, so completely obscured the
chromosphere for most of totality (see 'Transition to/from Totality"
and Inner Corona images above). Chromospheric arcs,
however, alternatively visible for a few seconds at the east/west
limbs of the Sun, became visible just as the silhouette of the
over-sized Moon covered those respective hemispheres of the Sun's
immediately adjacent (interior) to the respective solar limbs.
image above digitally combines the contact 2 and 3 chromospheric arcs
to show the appearance of the chromosphere as it would have appeared -
except at the solar poles - if the Moon had been a little further away
from the Earth. The chromosphere (also punctuated by
hydrogen-alpha red prominences) is "broken", in many places, many small
beads by the irregulaities in the lunar limb profile.
|A WALK AROUND THE SOLAR LIMB
Chromosphere (top) and inner corona
(bottom) remapped to a rectilinear projection.
Our view of circumsolar features is,
naturally, in a polar coordinate system with the polar "view point"
along the line-of-sight to the heliocenter. Above is an alternate
visualization, into a rectangular coordinate system where the
heliocentric gravity gradient is "up" at all circumsolar azimuth
angles. Such a polar de-projection
gives a locally "linear" view of the chromosphere tangent the limb and
coronal structures "evolving" vertically in the Sun's magnetic field,
but against the gravity gradient that is (everywhere) orthogonal
to the photosphere.
And then, at 20:39:48.6 UTC, totality
was over as the first bead of photospheric light appeared flanked by
capturing the instant of the end of totality. Ektar (ISO 25)
film. 1200 mm f/12.
All film-camera exposures were
autonomously acquired (as detailed HERE
) using G.
automated eclipse imaging software
, following a similar
inter-camera relative sensitivity paradigm as
detailed for imaging TSE