Common questions

Check the "Tonight's Chance" panel at the top of the Live page — it combines the Hp30 forecast, your local cloud cover, moon phase, and darkness to give you a plain-English answer. For the best chance you need: Hp30 4 or higher, dark skies (no moon, away from light pollution), and clear skies.

Hp30 4 brings the aurora to Scotland. Hp30 5 reaches northern England. Hp30 6 extends to central England. Hp30 7+ can cover most of the UK including London and Wales. The threshold shifts south as Hp30 rises — think of it as a tide coming in.

Hp30 is a geomagnetic index from GFZ Potsdam that measures how disturbed Earth's magnetic field is on a scale of 0–9 — the same scale as the older Kp index, but recalculated every 30 minutes instead of every 3 hours. That extra resolution catches the sharp onset of a substorm far sooner than Kp does.

Bz is the north-south component of the solar wind's magnetic field. When it turns negative (southward), it connects with Earth's magnetosphere and energy flows in to power the aurora. Bz going below −10 nT is a very good sign — go outside immediately. It's the single most important real-time number.

The equinoxes — late March and late September — tend to produce more frequent geomagnetic storms due to the alignment of Earth's magnetic field with the solar wind. Winter (October–February) also works well because nights are long, giving more dark sky time. Summer is mostly useless in Scotland and further north because nights barely get dark.

Only if Hp30 is low. At Hp30 5+ you have a good chance from northern England. At Hp30 7+ it can be visible from London and the south. For any display, you need dark skies — rural areas away from city glow give the best results, wherever you are.

Yes, at Hp30 5+, the aurora should be faintly visible to the naked eye from Scotland or a dark site in northern England — usually a green or whitish glow on the horizon. Stronger storms (Hp30 7+) show vivid green and often pink or red rays that are unmistakably aurora. Cameras pick it up more easily than your eyes at first.

Absolutely — modern smartphones are excellent. iPhone: use Night mode or a Pro/manual camera app. Pixel: Astrophotography mode in Google Camera. Other Android: Pro mode with ISO 1600 and a 5–10 second exposure. Key rule: keep the phone completely still (lean it against something or use a small tripod).

A good starting point for a DSLR or mirrorless: ISO 1600, shutter 10–15 s, aperture f/2.8 or wider. During an active display, drop the shutter to 3–6 s to freeze the motion. Use our Settings Calculator on the Guide page — it adjusts recommendations for your sensor type and activity level.

No. A smartphone on Night mode can take stunning aurora photos. An entry-level DSLR or mirrorless with a kit lens will give you a clear step up. You only need the more expensive gear (fast wide primes, full-frame sensors) if you want to push into video, timelapse, or very faint displays.

Use the 500 rule: divide 500 by your focal length × crop factor to get the maximum shutter time before stars streak. For a 24mm lens on APS-C (crop 1.5): 500 / (24 × 1.5) ≈ 14 seconds. Our Settings Calculator does this for you automatically.

Almost always camera shake. At 10+ second exposures even breathing can blur a shot. Use a tripod, set a 2-second self-timer or a remote shutter release, and turn off image stabilisation (it can fight against a stationary tripod).

The 3-day Hp30 forecast from GFZ Potsdam gives a rough indication of activity — it's useful for planning but not reliable for specific hours. The real-time Bz and solar wind data is far more actionable. If Bz goes suddenly and strongly negative, that's your cue to go outside right now, regardless of what the forecast said.

The 3D globe shows a rotating Earth with your home pin. You can drag to explore and double-click to set your home location. The globe updates automatically as new data arrives.

Click "Enable alerts" on the Live page and allow browser notifications. You'll get a push notification when geomagnetic activity rises past the threshold you set. You can also enable the sound alert — a distinctive tone will play through your browser when conditions improve.

The weather card needs your location to work. Tap or click "Use my location" to grant access, or search for your nearest town. Your location is stored in your browser only — it's never sent to our servers.

Hp30 index: every 30 minutes. Solar wind (Bz, speed, density): every 1–2 minutes via live socket connection. GOES magnetometer: every 2 minutes. Weather: every 10 minutes, and the card auto-refreshes in the background while you're on the page.

The sun constantly emits a stream of charged particles — the solar wind. When this wind carries a southward magnetic field (negative Bz), it reconnects with Earth's magnetosphere, channelling energy into the polar regions. Charged particles spiral down magnetic field lines into the upper atmosphere, exciting oxygen and nitrogen molecules which release light as they relax — that's the aurora.

Green comes from oxygen atoms at around 100 km altitude releasing energy at a wavelength of 557.7 nm — right in the middle of the visible spectrum where your eyes are most sensitive. Higher up (above 200 km), oxygen produces rare red aurora. Pink/mauve at the bottom edge comes from nitrogen molecules.

A geomagnetic storm is a disturbance in Earth's magnetic field caused by solar wind. Storms are classified G1 (minor) to G5 (extreme). G1 corresponds roughly to Hp30 5, G3 to Hp30 7, G5 to Hp30 9. The G5 storm in May 2024 was the strongest in 20 years and was visible across Europe including southern England.

The sun follows an approximately 11-year cycle of activity. Solar maximum is the peak of that cycle — sunspot activity and solar flares are most frequent. We are currently near or at solar maximum (around 2024–2025), meaning geomagnetic storms and aurora are more frequent than they've been for a decade.