The northern lights, or aurora borealis, were seen as far south as Cornwall in the UK on Sunday night, and are likely to be visible again on Monday night. Here’s how to spot them, says Stargazing at Home columnist abigail ball
Space
February 27, 2023
by abigail ball
The Northern Lights as seen from Duke’s Pass in the Trossachs, UK, on the night of February 26.
Reiss McGuire/Alamy
On Sunday night, the aurora borealis, or aurora borealis, was seen further south than usual, with glimpses even possible in Cornwall in south-west England. These displays of green and red flashes in the night sky, created by particles from the sun, are a wonder to behold. But if you missed them on Sunday, don’t worry, there’s still a chance to catch them this week, especially Monday.
What are the northern lights?
They are generated by the solar wind, a stream of charged particles that travel from the sun’s outer shell, or corona. Gusts of solar wind, called solar flares, pummel Earth’s magnetic field, which acts as a shield around the planet that deflects most particles. But at their weakest points around the poles, some penetrate the upper atmosphere, where they collide and excite or energize gas molecules. As these molecules lose energy again, they release photons of light that form auroras.
The type of molecule excited, together with the height of the collisions, determine the color of the aurorae. The most common are pale yellow and green from oxygen molecules at about 120 to 180 kilometers high. Less frequent are red auroras, generated from oxygen about 200 km from the ground, while red-purple auroras come from nitrogen below 100 km.
When is the best time to see the Northern Lights?
If the solar wind is active, the aurora can be seen as soon as it gets dark.
Where will the Northern Lights be seen tonight?
The stronger the solar flare, the further south they will be visible. It takes about a day for the particles to travel to Earth, so we can predict a day in advance how strong the aurora will be. The UK Met Office says the lights are likely to be visible again there on Monday night, perhaps even across central or southern England. Throughout the rest of the week, keep an eye on forecasts like the Met Office and other auroral forecasting apps.
When should you look for the lights?
There are websites and organizations that monitor the sun that can give a forecast for the next day or even for the week. he US National Oceanic and Atmospheric Administration site., for example, provides observations for the past three days along with 30-minute predictions of solar activity. This is measured using the planetary K index, or Kp, on a scale of 0 to 9. The higher the value, the more activity. To see the lights with the naked eye in central England, a Kp value of 8 is usually required. the free app Aurora UK Clock It also has aurora forecasts every half hour, and you can set up an email alert to make sure you’re ready for any celestial light show.
How can you see the Northern Lights?
Go to a dark spot as far away from any light pollution as possible. If you’re not sure where to go, find a dark place and look toward the northern horizon. So you need to wait and let your eyes adjust. But don’t expect auroras with the impressive and bright colors shown in the photos. When seen with the naked eye, auroras are much more subtle and can be difficult to spot the first time you try. If you have a camera with a digital screen, looking through the screen can help you confirm that you are looking at auroras, as they can sometimes appear greenish-white to the eye, but very green on the camera. Keep an eye on the weather forecast as well, as you won’t see any Northern Lights if you have cloudy skies.
How to take screen shots
Most smartphone cameras will be able to capture the green hues of the Northern Lights. If you have a digital camera and a tripod, try a long exposure with the shutter speed set to a few seconds.
