The Northern Lights

Photos From Ireland

Northern Lights – Aurora Borealis

One of my passions I would even say its a photography addiction is photographing the Northern
Lights or the Aurora Borealis as they are sometimes known as. I am lucky to live in one of the
best places in Ireland right here in Co. Donegal to see and capture them on camera.
I am often asked what exactly are the Northern Lights – Aurora Borealis? Let me explain.

What are the Northern Lights?
The Northern Lights are the result of electrically charged particles from the sun colliding that
enter the earth’s atmosphere. The skies above the magnetic poles of the northern and southern
hemispheres are where they can be seen. In the northern hemisphere they are known as ‘Aurora
Borealis’ and ‘Aurora Australis’ in the southern hemisphere.
These beautiful lights shows have many different shapes and colours with greens, yellows and
some pinks most often seen. Different shades of red, yellow, green, blue, and violet have been
seen and I have seen them take many different shapes from giant curtains, to gentle arcs and
rays that shoot up into the sky.

Gaseous particles in the Earth’s atmosphere collide with electrically charged particles released
from the sun’s atmosphere. The different colours that can be seen depend on the type of gas
particles that are colliding. The most common auroral colour, a pale yellowish-green, is produced
by oxygen molecules located about 60 miles above the earth. Rare, all-red auroras are produced
by high-altitude oxygen, at heights of up to 200 miles. Nitrogen produces blue or purplish-red
aurora. The most common ones that I have seen here in Donegal have been greens, yellows,
pinks and reds.
Where are the best places to see the Northern Lights – Aurora Borealis
You have a better chance seeing the Northern Lights the further north you go, for example Co.
Donegal is going to give you a better chance than say if you were living in Cork. You need to go
somewhere dark, very dark, with no light pollution, you need to have weather conditions that
have clear skies bit very little if any moonlight as these factors can all affect your chances of
seeing them. My favourite place is Inishowen in Co. Donegal where I live as I am living right up at
the top of the country with very dark skies and little to no light pollution.

How can you tell when they will happen?
This is difficult to do but there are a few things you can do to increase your chances of seeing
them. First of all look at the weather forecast for where you are planning to go to and if you have
clear skies with no rain or bright moon light your chances are better. Next thing to check is the Kp
readings, what is that you ask? The Kp number is a system of measuring aurora strength. It goes
from 0 to 9 (0 being very weak, 9 being a major geomagnetic storm with strong auroras visible).
Video below shows a time lapse that I created several years ago of the Northern Lights.
So when your looking at the aurora forecast page, you want to see high Kp numbers. The higher
the better. Anything above (and including) Kp5 is classed as a geomagnetic storm. A good
explanation can be found at http://www.aurora-service.eu/aurora-school/all-about-the-kp-index/
Another website that I use is http://softservenews.com/ now here is where I have got caught out
in the past and I learned the hard way. Generally if you get a Kp reading over 4 you will have a
decent chance if everything I have mentioned previously lines up, but there is another factor that
comes into play.

Real Time Bz
Bz is the solar wind’s magnetic orientation in the up/down direction. Although an Aurora can
happen with a positive Bz, a negative Bz is generally better. A negative Bz helps the solar wind
grab the earth’s magnetic field which can more easily lead to an Aurora. So a negative Bz is
good. The more negative the better.
Each number in the diagram below represents a rolling 5 minute average of the Bz taken along
the length of the solar wind stream. This data comes from a satellite about 1 million miles from
earth. These 5 minute stream segments are all headed towards earth. They should arrive in 20 to
40 minutes. They are given in the order they’ll hit earth, with the first 5 minute average hitting
first. Think of each number representing a 5 minute long cloud of solar wind speeding towards
earth. Remember, it’s best for Bz to be negative, and the more negative, the better.

OK let’s look at it another way, imagine the earth encased by a Christmas snow globes.

This protective snow globe around the planet weakens and strengthens all the time. So let’s say
we have a Kp reading of 9 but the Bz reading is +10 this means although we have a really good
strong aurora we also have a really strong protective barrier around the planet protecting us from
what’s coming from outer space which also included the aurora. Our chances now of seeing a
display are going to be very slim. Now at the other extreme let’s say we a Kp reading of 3 and a
Bz reading of -25 although the Kp is only 3 we would normally only pick this up on the camera
and not by the naked eye but because we have practically have no barrier around the globe we
could have a very good strong display. What you ideally want to have is a good high Kp reading
and a negative – Bz reading together then your chances of seeing a really good display really
increase. Be warned though you really only get approx thirty minutes warning if there is a good
chance of a display and even at that it can die away all of a sudden.

What camera equipment and settings do I need?
People think you can only see the aurora on a camera but the fact is if you get a strong enough
display you will see this with your naked eye. You don’t need any special filters but what you will
need is a DSLR camera, wide angle lens that you can shoot wide open for example F/2.8, a
strong sturdy tripod, remote shutter control either wireless or a cable release, fully charges
batteries and spare memory cards. My normal go to settings for photographing the Northern
Lights are shooting at F/2.8, shutter speed 20 seconds and ISO at 800. I adjust these according
to the display, in fact I always shoot at the same F stop and never increase the shutter time or
else your stars will not be as sharp they will begin to blur due to the earth’s rotational movement,
in fact if I get a really powerful display I will decrease the shutter speed. I adjust my ISO
according to the nights display.
You will also needs loads of patience and good luck to see them and it’s a good idea to go to the
location in daylight to see is there any hazards that you can fall or trip over that you may not be
aware off when it gets dark. Always tell a friend where your going and what time you expect to be
home at as well and if you are near the coast please be very careful of incoming tides and
slippery rocks.

Check out some of my images that I have taken over the years here locally in Co. Donegal. You can also purchase them at www.photosfromireland.com/northernlights we also do
photography tours and workshops at night and day as well.

Any questions please feel free to get in touch we would be more than happy to hear from you.

www.photosfromireland.com