K Y I N F O R M A T I O N
STARGAZING TIP SHEETS
HOW TO PREDICT & WATCH
AURORAS FROM SOUTHERLY LOCATIONS
it or not, middle- and low-latitude
locations (including much of the U.S., Europe
and Asia) can receive one or two displays of
the northern lights each year. But if
you're not under a dark, moonless rural sky
you can't possibly see them. This
photo shows a display on May 14/15, 2005 from
my front yard in the Anza-Borrego desert of Southern California!
There's no right or wrong way to determine
when an aurora might appear in our sky, but
the following steps outline what works for
me. They may seem confusing at first,
but with a little practice you'll figure it
1. Heads Up!
The first place I usually learn about an
impending auroral display is
SpaceWeather. I visit this
only for all the cool photos, but also
to learn if the sun's doing
something that may lead to a auroral
You can also keep up with the lights on
the Facebook Group at
2. Is tonight the night?
If auroral activity seems possible as
evening approaches, I begin to monitor conditions
at the Earth itself.
auroral visibility oval shows the
likelihood of seeing an auroral display.
Usually it's green and relatively small.
But as activity picks up over time, the
oval can become yellow, orange or even red,
and can swells over much of the continental
U.S. If my location is within, or
near the edge of, the expanded oval, I'm definitely on the lookout.
However, an even more straightforward
graphic that shows the probability of
seeing the aurora in your area is the
If you have to choose only one indicator
to watch for real-time activity in your
location, this is it!
Another indicator I watch is the
Estimated Planetary Index (Kp)―a
scale of global magnetic activity that
runs from 0 to 9. When Kp
is low the vertical bars are green; when
is moderate, they are yellow. Only
when the most recent Kp is 8 or
the bars turn red am I ready for action.
Sky watchers farther north than Southern
California might see a display when Kp
3. Holy Moley... It's Showtime!
As darkness falls and a display
seems imminent, I next turn my attention
to real-time data from the ACE
spacecraft (Advanced Coronal Explorer)
which measures solar material heading
First I watch the
interplanetary magnetic field (Bz)―the
red curve at the top.
This is measured by ACE which lies
between us and the sun, and usually
gives a 20-40 minute preview of
conditions heading our way. Only
when Bz is solidly negative
(south) will auroras be likely in
southerly areas. Material density
and velocity are also key indicators to
IS IT REALLY THE AURORA?
Conditions for an auroral display can change
rapidly and, even though the numerical
indicators suggest a display is likely,
Mother Nature may have other ideas.
The lights might appear from here as only a
faint gray smudge against the dark sky;
sometimes we can see faint color or even
some vertical rays dancing back and forth in
the northern sky. Moonlight can easily wash out
any chance of seeing them.
Long exposure photos will often show red, green
or blue in the lights. This is a good
way to determine if it's auroral light or
just distant light pollution. If you
have a digital camera, take several shots
toward the north; if you see evidence
of any of these colors―or even signs of
vertical rays―you may have an aurora
brewing. This photo was shot just
before dawn on July 27, 2004 from Borrego
Springs in the Anza-Borrego Desert of
To photograph the lights, use a normal or
wide-angle lens and open the aperture all the way, set your ISO to 400 or so and,
with your camera on a tripod, take exposures
of 15-60 seconds. Of course this
depends on their brightness and how fast
they're moving. Don't be afraid to
experiment to get the best shots.
KEEPING WATCH UP NORTH
Seeing the lights from southerly latitudes
is really a treat, but it's nothing like the
show one gets from near latitude 65 degrees
While I'm waiting for those rare displays
here in Southern California, I like to keep
watch on the skies over Fairbanks,
Alaska―the Aurora Capital of the World―with
Aurora Webcam at the
Poker Flat Research
Range. Of course, it only operates
when it's dark (which means not during the
summer months!) During a good display
in fall, winter or spring, the colors and
movement of the aurora are stunning to
watch. The image refreshes every
five minutes. Unfortunately the webcam
has lost its funding and is not operating at
There are others as well;
they also operate only when it's dark.
SEEING THE REAL THING
It's fun to monitor the aurora from afar, or
even to see it from southern latitudes.
But to experience the real thing, join me on my
exciting and very popular public
witness and photograph the greatest light
show on Earth!
Check out our offerings here!