Coronagraph white light images
from both space and on the
ground show the coronal density
structures called streamers, plus
coronal activity projected
beyond the limb. The "halo" CME
events, observed as rings or
partial rings around the Sun, are
thought to be a good predictor
of a geomagnetic storm several
days later. White light
photospheric images from
ground-based telescopes and
TRACE of course show where
these coronal transients and
other features are located with
respect to sunspots.
The top images were made
available by the SOHO LASCO
investigation team. The right
panel includes a fairly ideal halo
event. An image of a coronal
transient made with the
ground-based coronagraph at
Mauna Loa Observatory,
operated by HAO, is shown
below. HAO also houses the
archive of images from the SMM
spacecraft coronagraph, which
covers a significant part of a
solar cycle. An example of a CME
picture from the SMM archive is
included here. NASA's planned
dual spacecraft mission,
STEREO, will obtain
coronagraph images from several
perspectives to provide an
observational basis for 3D
reconstruction of coronal
features.
Click on the top two images to the left to view the corresponding
animation. Click on the bottom two images to enlarge.
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