Imaging the Aurora Borealis
In most
years, one or more displays of the aurora borealis can be seen from
mid-Michigan, despite the clouds which seem to delight in getting in the
way. It is relatively easy to get a photograph
of the aurora, although still photos often give no sense of the lively motion
seen in many displays. The images shown
here were usually taken a few miles north of the Lansing area, to put the city
lights to the south. Time exposures are
ordinarily needed with either digital or film cameras, and those shown here
typically range from about 5 seconds to 15 seconds in duration. Longer exposures can show fainter detail, but
rapidly moving portions of the aurora can be blurred.
Most
spectacular are the aurora displays seen during large geomagnetic storms, which
can be triggered when an ejected coronal mass strikes the Earth’s
magnetosphere. These are more likely to
be seen when the Sun is very active, with large sunspot groups and strong solar
flares. However, even when the Sun is
relatively quiet, near solar minimum, solar winds from coronal holes can
produce modest auroral displays low in the northern
sky.
Images of a
few relatively strong auroral displays in
mid-Michigan:
Here are
images of weaker auroras, such as might be associated with coronal hole streams:
More aurora images can
be found here.
